Abnormal Loading on Buildings and Progressive Collapse. an Annotated Bibliography NATIONAL BUREAU of STANDARDS

AlllDQ

NATL INST OF STANDARDS & TECH R.I.C.

A1 11 00992794 /Abnormal loading on buildings and proar TA435 .U58 V67:ll76 C.I NBg-PUB-C 1876 BUILDING SCIENCE SERIES

Abnormal Loading on Buildings and Progressive Collapse. An Annotated Bibliography NATIONAL BUREAU OF STANDARDS

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hot OicC Abnormal Loading on Buildings and Progressive Collapse.

An Annotated Bibliography

E. V. Leyendecker

Center for Building Technology Institute for Applied Technology National Bureau of Standards Washington, D.C. 20234

J. E. Breen

Department of Civil Engineering University of Texas at Austin Austin, Texas 78712

N. F. Somes

Office of the Director Institute for Applied Technology National Bureau of Standards Washington, D.C. 20234

M. Swatta

Bechtel Corporation San Francisco, California 94105

Sponsored by Office of Policy Development and Research Department of Housing and Urban Development Washington, D.C. 20410

U. S. DEPARTMENT OF COMMERCE, Rogers C. B. Morton, Secretory

James A. Baker, III, Under Secretary Dr. Betsy Ancker-Johnson, Assistaryt Secretary for Science and Technology NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

Issued January 1976 —

Library of Congress Cataloging in Publication Data

Main entry under title: Abnormal Loading on Buildings and Progressive Collapse. (National Bureau of Standards Building Science Series; 67) Includes Indexes. Supt. of Docs. No.: C 13.29/2:67 1. Structural Stability—Bibliography. 2. Building Failures Bibliography. 3. Structural Design—Bibliography. I. Leyendecker, E. V. II. United States. Dept. of Housing and Urban Development. Office of Policy Development and Research. III. Series: United States. National Bureau of Standards. Building Science Series; 67. TA435.U58 No. 67 [Z5853.S86 TA656] 690'.08s [016.691 75-619098

National Bureau of Standards Building Science Series 67

Nat. Bur. Stand. (U.S.), Bldg. Sci. Ser. 67, 60 pages (Jan. 1976) CODEN: BSSNBV

U.S. GOVERNMENT PRINTING OFFICE WASHINGTON: 1976

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 (Order by SD Catalog No. C13. 29:2/67). Price $1.20 cents. (Add 25 percent additional for other than U.S. mailing) Stock Number 003-003-01468-1 SI Conversion Units

In view of present accepted practice in this technological area, U.S. customary units of measurement have been used throughout this report. It should be noted that the U.S. is a signatory to the

General Conference on Weights and Measures which gave official status to the metric SI system of units in 1960. Readers interested in making use of the coherent system of SI units will find conversion factors in ASTM Standard Metric Practice Guide, ASTM Designation E 380-72 (available from American Society for Testing and Materials, 1916 Race Street, Philadelphia, Pennsylvania 19103). Conversion factors for units used in this paper are:

Length

1 in = 0.0254* meter

1 ft =0.304S* meter

Area

1 in- = 6.4516* X 10-' meter-

1 ft^ =9.2903X10-2 meter-

Force

lib (Ibf) =4.448 newton 1 kip =4448 newton

Pressure, Stress

1 psi = 6895 pascal (N/m-) 1 psf = 47.88 pascal (N/m^)

Moment

1 lbf-ft= 1.3558 newton-meter

Exact value i

i Contents

Page

SI Conversion Units iii

Introduction 1 Chronological Bibliography, 1948 through 1973 3 Author Index 51 Subject Index 53

Abnormal Loading on Buildings and Progressive Collapse. An Annotated Bibliography

Edgar V. Leyendecker, John E. Breen,* Norman F. Somes, and M. Swatta **

This bibliography on the subjects of abnormal loading and progressive collapse is an annotated listing of articles that have appeared in the technical literature from 1948 through 1973. The entries have been arranged chronologically by year and alphabetically within years. Both subject and author indexes have been included. The references listed have been selected as most representative of the historical background and best representing the origin and present state-of-the- art of current practice without undue repetition of data. References pertaining to characteristics, frequencies, incidents, tests, design procedures, and regulations for many types of abnormal loadings are included. Among these are various types of accidental impacts, construction loads, explosions, faulty practices, and extreme atmospheric loads. Heavy emphasis was placed on referencing applicable building codes and regulations pertaining to the subjects of progressive collapse and abnormal loadings. This bibliography also contains numerous references to contemporary professional opinion as expressed in editorials and discussions of the subject and, particularly, on the various regulations proposed. A large number of proposed analysis and design procedures, as well as applicable test results, are referenced. In addition to the general reference material, a careful search was made of the ten most recent years (1%4-1973) of Engineering News Record to identiy and annotate possible progressive collapse examples from building failures reported by that publication.

Key words: Abnormal loading; alternate path; annotated bibliography; bibliography; building regulations; collapse; failures; progressive collapse; specific resistance.

1. Introduction This bibliography ^ on the subjects of abnormal loading and progressive collapse is an annotated list- There has been growing international concern ing of articles that have appeared in the technical that buildings, particularly multistory buildings, may literature from 1948 through 1973. The references be subjected to loading conditions not normally con- listed in this bibliography have been selected as most sidered in design, i.e., abnormal loadings. This con- representative of the historical background and best cern was intensified with the Ronan Point apartment representing the origin and present state-of-the-art of collapse in London, England, in 1968. In this 22-story current practice without undue repetition of data. building of precast concrete panel construction, col- Since the bibliography is intended as a reference docu- lapse was triggered by a gas explosion in the kitchen ment on the subject of progressive collapse, it was of an apartment on the 18th floor. The explosion blew made as complete as possible. The references cover out an exterior wall panel; the loss of support pro- a broad range of structures, such as apartment build- vided by the panel resulted in a chain reaction of col- ings and bridges, both during and after construction. lapse to the roof. The collapse also progressed almost Thus, the reader with a narrow interest, such as completed find literature to the groimd as debris from above fell on successive apartment buildings, will the of floors below (see figure 1). This type of chain reac- direct interest, while at the same time having available tion or propagation of failure following damage to a a comprehensive listing of references covering the relatively small portion of a structure has been termed broad category of progressive collapse. "progressive collapse." Because the heightened interest in the subjects of collapse both A Commission of Inquiry Report [84] ^ and subse- abnormal loadings and progressive quent studies of the Ronan Point collapse revealed a stemmed from the Ronan Point incident, it was im- into number of deficiencies in existing codes and stand- practical to attempt to divide the bibliography ards, particularly as they applied to multistory con- exclusive subsections. Instead, the entries have been struction. In the United Kingdom interim criteria for arranged chronologically by year and alphabetically both the appraisal and strengthening of existinir buildins^s within years. For the convenience of the user, and the design of new structures were quicklv imple- subject and author indexes have been included. The the index mented. Several other countries in Europe introduced numbers following the subjects or names in the bibliogranhy. additional design criteria to deal explicitly with the refer to the individual references in throughout. Some risks exposed by the incident. Annotations have been included have been obtained from such sources as the Ennineer- ing Index, Building Science Abstracts. Applied Me- chanics Reviews, and the Geodex Structural Index. Many were prepared by the project staff.

1 brackets designate literature references listed in the * Professor of Civil Engineering, The University of Texas at Figures in bibliography. Austin, Austin, Texas. = Research sponsored by the Office of Policy Develoment and Re- ** Structural Engineer, Bechtel Corporation, San Francisco, Cali- search. Department of Housing and Urban Development. Washington. fornia. D. C. 20410.

1 collapse, Figure 1. Ronan Point apartment building after the with a second identical building in the background.

(Courtesy of London Express News and Feature Services.)

2 Examination of the subject index indicates the far- out of the war was the high resistance of framed reaching scope of the bibliography. References per- buildings to the effects of high explosives. taining to characteristics, frequencies, incidents, tests, design procedures, and regulations or many types of abnormal loadings are included. Among these are 1949 various types of accidental impacts, construction loads, 2. Thompson, N. F., and Cousins, E. W., Explosion explosions, faulty practices, and extreme atmospheric Tests on Glass Windows. Effect on Glass Break- loads. References are multiple listed as appropriate age of Varying the Rate of Pressure Application, with particular collapse examples identified by geo- Journal of the American Ceramic Society, Vol. graphical location as well as by type of failure. In 32, No. 10, 1949, 313-315. addition to the general reference material, a careful pp. search was made of the ten most recent years of En- Tests were made to determine the effectiveness gineering News-Record to identify possible progressive of glass windows in preventing building damage collapse examples from structural failures reported by from , internal explosions involving combustible that publication. In keeping with the general nature of dusts or vapors. It was found that the effective this bibliography, failure of different types of struc- strength of glass panes increases in an approxi- tures is included. These items list many examples of mately linear ratio with increased rate of pres- both vertical and horizontal progressive collapse which sure appbcation. It was concluded that window have occurred in recent years other than the well- glass is of dubious value for explosion venting known Ronan Point incident. Also included are a num- purposes, except possibly for explosions of high ber of examples involving major abnormal loadings pressure but of very short duration, such as such as large scale gas explosions and formwork fail- those that might occur if small quantities of ures where progressive collapse might be expected but high explosive were placed relatively near the did not occur, since this helps focus on the resistance windows. of many conventionally designed and constructed buildings. For all specific failure examples, an attempt was made to classify the failure mode and to 1950 identify possible progressive collapses in the subject 3. Amirikian, A., of Protective Structures, index under the heading Failure Modes, Progressive. Design P51, Department of the Navy, Heavy emphasis was placed on referencing appli- NAVDOCKS Bureau of Yards and Docks, Washington, D.C., cable building codes and regulations pertaining to the August 1950. subjects of progressive collapse and abnormal loadings. as Subject index headings such Building Code Protective design is a common problem for and Recommendations lead to major regulations issued military installations as well as for civil and to cope with this subject area. Numerous citations industrial buildings. This paper presents certain are included under the headings Alternate Path and data and design procedures in two parts. The Specific Resistance, which have come to represent the first part includes declassified experimental data most general way of codifying requirements for en- and a procedure used by the Bureau of Yards suring safety against progressive collapse. and Docks of the Navy Department in designing This bibliography contains numerous references to structures to resist conventional weapons of contemporary professional in edi- opinion as expressed World War II, such as bombs and projectiles. torials and discussions of the subject and, particularly, The second part develops a discussion of atomic on the various regulations proposed. A large number bomb blast and a new concept of structural re- of proposed analysis and design procedures, as well as sistance. Based on this concept, an analysis is appplicable test results, are referenced. The general presented, together with a simplified procedure subject of risk analysis with emphasis on applications for the design of structures to resist atomic to multistory buildings is included. blast.

2. Chronological Bibliography, 1948 1951 through 1973 4. Cousins, E. W., and Cotton, P. E., Design of 1948 Closed Vessels to Withstand Internal Explosions, Chemical Ejigineering, London, Vol. 58, No. 8. 1. Baker, J. F., WilUams, E. L., and Lax, D., The August 1951, pp. 133-137. Design of Framed Buildings Against High Ex- Tests were conducted with rupture disks to plosive Bombs, The Civil Engineer in War, Lon- provide data on the effect of disk strength and don, Institution of Civil Engineers, Vol. 3, 1948, vent area on the maximum explosion pressure pp. 80-112. of an internal explosion in closed vessels. Vari-

The experience of engineers in England dur- ables included vessel size and strength ; mixtures ing World War II is documented. It was con- of hydrogen and air; and mixtures of propane cluded that one of the outstanding facts to come and air.

3 5. Damage Control in Wartime, Studies in Business 1955 Policy No. 53, National Industrial Conference Board, September 1951. 8. Brook, D. H., and Westwater, R., The Use of Ex- plosives for Demolition, Proceedings, Institute The results of an extensive study of how of Civil Ejigineers, London, Vol. 4, No. 3, P. European companies protected personnel and Ill, December 1955, pp. 862-899. minimized industrial damage during World War II are contained in this and the companion re- The authors feel that the use of explosives in port. Protecting Personnel in Wartime. It is civil demolitions involves problems sufficiently pointed out that damage can be controlled by different from military demolitions to justify action taken before, during and after at- this paper. After outlining types of commercial tack. The principal hazards are blast, splinters, explosives and accessories most suitable for and fire, and of these, fire is the most destruc- demolition work and dealing with the methods of tive. Preparatory measures dealing with these initiating them, the paper points out that there factors are explained. Contains tables and graphs are only three ways in which explosives can be which simplify determination of blast pressures used for demolitions, namely, as lay-on charges, for various sizes and types of bomb explosions as concussion charges, and as shot-hole charges. and distances from center of explosion. Each of these ways in which explosives can be used is considered and examples are given of actual operations.

1952 9. Whitney, C. S., Anderson, B. G., and Cohen, E., Design of Blast Resistant Construction for 6. Nielsen, K., Loads on Reinforced Concrete Floor Atomic Explosions, Journal of the American Slabs and Their Deformations during Construc- Concrete Institute, Vol. 26. No. 7, March 1955, tion, Proceedings N:R 15, Swedish Cement and pp. 589-683. Concrete Research Institute at the Royal Insti- tute of Technology, Stockholm, 1952. Methods and principles used in designing the first full scale blast resistant structures tested This report summarizes analytical and ex- at Eniwetok are presented and the test results perimental studies of the magnitude of construc- are cited in support of the procedures outlined. tion loads on reinforced concrete slabs in multi- Ex;onomic and other practical considerations are story apartment buildings. The study indicates discussed. Radiation hazards and methods of that in typical cases measured loads up to 200 dealing with them are described. Appendices are percent of slab dead load were observed while included which give detailed procedures for calculations indicate possible loads up to 250 computing the blast loading, for designing in- percent of slab dead weight. The influence of dividual structural elements and single and multi- rate construction, method of slab support, rigid- story buildings in both the elastic and plastic ity of formwork and moisture content of form range for this loading, for computing ultimate lumber were studied. strength of structural elements and frames under rapid loading, and for dealing with some special 7. Windowless Structures, A Study in Blast-Resistant problems. Design, TM—5—4, Federal Civil Defense Admin- istration, U.S. Government Printing Office, Wash- ington, D.C., June 1952. 1956

This manual is one of a series of publications dealing with protective construction and pro- 10. Granstrom, S. A., Loading Characteristics of Air vides technical data for architects and engin- Blasts from Detonating Charges, Transactions eers interested in designing buildings which will of the Royal Institute of Technology, Nr. 100, afford protection from atomic blasts. Methods Stockholm, Sweden, 1956. and procedures for designing windowless structures based on the dynamic properties of load- The purpose of the report is to clarify the ing are described. These principles are appli- loading effects produced on structures by air cable to windowless portions of conventional blasts from detonating charges. Pressure-time buildings. Principles, methods, and formulas for curves are presented to show the effect of a 1 kg determining the magnitude, duration, and dis- charge of TNT at selected distances. tribution of atomic blasts loads on windowless 11. Newmark, N. M., An Bjigineering Approach to structures are also presented. This publication Blast Resistant Design, Transactions of the is of interest to architects and engineers con- American Society of Civil Engineers, Vol. 121, cerned with the design of conventional struc- 1956, pp. 45-64. tures because many such structures can be made blast-resistant in whole or in part by the addition The problem of blast-resistant design is ap- of relatively inexpensive design features. proached directly by means of reasonable sim-

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plifying assumptions. The resulting design pro- 1960 cedure avoids time-consuming and misleading 15. Collapse Blamed on Bearing Failure, Engineering analysis. The author presents the procedure News-Record, 28. and the necessary mathematical relationships Decemher 15, 1960, p. and explains their practical application. A building collapse near Harrisonburg, Vir- ginia, has been attributed to bearing failures at 1957 the beam-column connection. The accident occurred as erection crews started on a new bay 12. Teichmann, G. A., and Westwater, R., Blasting adjacent to a 24,000 ft' area that had been and Associated Vibrations, Engineering, Lon- erected. Framing of the one story bays were don, Vol. 183, No. 4753. April 12, 1957, pp. prestressed double tees of 50 ft span bearing 460-465. on the top flange of prestressed I-beams.

The major differences between blasting vibra- 16. Legget, R. F., and Schriever. W. R., Realistic tions and what might be termed industrial vi- Assessment of Loads Acting on Structures with brations is the continuity of the latter over the Particular Reference to Snow and Wind Loads sudden arrival and dying of the former. The on Buildings, VI Congress of the International authors have studied this problem in an en- Association of Bridge and Structural Engi- deavor to clear up some of the misconceptions neers (Preliminary Report), 1960, pp. 85—95. relating to blasting vibrations and explain The paper points out that no structure, no present-day views and methods applied to matter how conservatively designed, provides counteract problems arising from this cause. for absolute safety, because loads and carrying capacities of structures are variables whose 1958 upper and lower limits respectively, cannot be predicted with certainty but only in terms of 13. Monk, C. B. Jr., Resistance of Structural Clay probability of failure. Advances in structural Masonry to Dynamic Forces, Research Report design must be accompanied by corresponding No. 7, Structural Clay Products Research Foun- improvement in the knowledge of actual loads dation, Geneva, Illinois, November 1958. on structures. Canadian studies of live loads on buildings, and particularly a countrywide This reports the results of the Structural Clay survey of snow loads on roofs, are described Products Research Foundation studies of the with relation to their application in the Na- problems of blast resistant design. Tests to gain tional Building Code of Canada. some insight on the behavior of clay masonry subjected to high impulsive forces revealed that effective designs in clay masonry could be 1961 achieved through the use of reinforced brick 17. Design of Structures to Resist Nuclear Weapons masonry and the arching of unreinforced ma- Effects. American Society of Civil Engineers, sonry walls. Included in the report are criteria Manual of Engineering Practice, No. 42, New for blast resistant design, structural theory, and York, 1961. structural design techniques. WTiile this reference principally treats de- 1959 sign for nuclear blast, sections on choice of materials, details, dynamic strength of mate-

14. Norris, C. H. et al., Structural Design for Dy- rials, and dynamic design are generally ap- namic Loads, McGraw-Hill, New York, 1959. plicable for any type explosion.

To cover the broad field of structural design for dynamic loading, the book is divided into 1962 four parts, covering behavior of materials, an- 18. Firnkas, S.. Continuity of Prestressed Concrete alysis of dynamic response, definition of dy- Girders Under Ultimate Load Conditions. Pre- namic loads, etc., as well as specific propor- stressed Concrete Institute Journal, Vol. 7, tioning and dimensioning of structural mem- No. 3, June 1962, pp. 45-54. bers as follows (1) Behavior of Materials under Dynamic The paper discusses the possibilities of an Loading. accident-proof continuitv connection of precast/ (2) Calculation of Response of Structural prestressed concrete beams, and outlines the Systems to Dynamic Loading. basic considerations that went into the design (3) Modern Computational Techniques Ap- of the connection. In addition, it was indi- plicable to Response Calculations. cated how a precast concrete structural system (4) Application of Structural Design and using individual parts and beams designed for Analysis to Specific Cases Involving Dy- simple spans can obtain the additional advan- namic Loading. tages of a continuous system under ultimate

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conditions. Furthermore, it is an important 23. Shapiro, G. A., and Sokolov, M. E., 0 Procnosti I step in preventing accidents and injuries in an Deformativnosti Gorizontalnycm Stykov Krup- industrial plant with operations that can cause nopanelnych Zanij (On the Strength and De- damage to the structure hy unintentional formability of Horizontal Joints in Large Panel

negligence. Walls ) , Beton i Zelezobeton, 6, 1963.

19. McKaig, T. H., Building Failures, Case Studies Based on test results of a number of typical in Construction and Design, McGraw-Hill Book wall-floor joint details, design recommendations Company, New York, 1962. are given for determining horizontal joint strength as a percentage ot wall strength con- A review of numerous cases of building fail- sidering important parameters such as the rela- ures which have occurred in the United States. tive strength of the mortar in the joint and the Although the book was written well prior to concrete strength of the wall, the width of the the entry of the term "progressive collapse" wall and the width of beaming of the slabs. into general engineering vocabulary, several The relative thickness of the slabs to be joined cases of chain reaction can be seen. at a joint is also shown to be an important factor. 1963 1964 20. Flat-Slab Garage Roof Caves In, Engineering News-Record, January 3, 1963, p. 16. 24. Cairo Building Collapse Kills 31, Elngineering News-Record, October 29, 1964, p. 15. A three year old concrete roof over an under- ground garage collapsed in New York City on The sudden complete collapse of a five-story December 23. The 16 in deep grid flat slab bearing wall reinforced concrete apartment roof supported a 4,500 ft^ landscaped area at building in Cairo, Egypt took 31 lives. The street level. According to an official of the owner started with a two-story structure and New York Department of Buildings, shear caps progressively added new floors. Overloading of shown in the design drawings were omitted in the soil foundation resulting from the continued construction. The slab apparently failed in addition of new floors allegedly caused the diagonal tension at six interior columns with collapse. missing shear caps. 25. Chandler, S. E., Fire Incidents Involving Ex- 21. Grundy, P., and Kabaila, A., Construction Loads plosions, Joint Fire Research Organization, on Slabs with Shored Formwork in Multistory Fire Research Note No. 541, England, March Buildings, Journal of the American Concrete 1964. Institute, Vol. 60, No. 12, December 1963, pp. 1729-1738. This statistical survey pertains to the number of fixes in which explosions occurred during the Construction loads in a concrete structure years 1961 and 1962. The number of fire in- where upper floors are shored from lower floors cidents involving explosions, estimated from 1 may exceed design service loads by an appre- in 2 samples of all reports, were 426 in 1961 ciable amount. A method for determining these and 498 in 1972. Of those, the numbers in erection loads is presented for flat slab or flat which water or space heating equipment was plate construction. The effect of shoring differ- the heat source were 144 in 1961 and 192 in ent numbers of floors and the effect of con- 1962. Space and water heating equipment were struction loads on design are also discussed. revealed as the main sources of damage. The principle causes of explosions in 1962 were gas 22. Northwood, T. D., Crawford, R., and Edwards, (town) leaks (40 incidents), domestic back A. T., Blasting Vibrations and Building Dam- boilers (18 incidents) and foreign matter on age, The Engineer, London, Vol. 215, No. S coal fires (17 incidents) 601, May 1963, pp. 973-978. 26. Feld, J., Lessons from Failures of Concrete Struc- Building vibration building re- and damage tures, American Concrete Institute Monograph 5 sulting from blasting operations were studied in No. 1, ACI/Iowa State University Press, 1964. j a series of experiments on expendable buildings. Sixty charges ranging from 0.3 lb to A survey of concrete structure failures re- 1600 lb were set off at distances of 3 ft to ported over a 60-year period with selected 300 ft from the buildings under study. Observa- cases illustrating major factors causing such tions were made of vibration displacement, failures. Monograph includes a discussion of velocity, acceleration and strain of the building formwork and construction problems leading structures. The results supported previous con- to progressive collapses and has several ex- clusions that particle velocity is the most useful amples of roof structures which experienced indicator of the onset of damage. horizontally propagating progressive collapses.

6 27. Mayes, W. H., and Edge, Jr., P. M., Effects of structural member of the test houses was stressed Sonic Boom and Other Shock Waves on Build- beyond 59 psi. The overpressures did not cause ings, Materials Research and Standards, Vol. good-quality, propery installed window glass 4, No. 11, November 1964 pp. 588-593. to break. Deflection of the main structural elements of the test houses was negligible. This paper discusses the sonic boom damage problem, summarizes 3000 complaints received 31. Ramsay, W. A., Damage to Ottawa Air Terminal by the Air Force because of military flights, Building Produced by a Sonic Boom, Materials and describes experiments with a building ex- Research and Standards, Vol. 4, No. 11, No- posed to sonic boom overpressures, acoustic vember 1964, pp. 612-616. loading from a rocket, and overpressures from explosive blasts. Complaints from building res- Damage amounting to approximately $300, idents suggest that secondary components such 000 to an almost completed air terminal build- as plaster, masonry, and glass are susceptible ing by a supersonic fighter aircraft accidentally to damage. Building response measurements in- passing over the building in a demonstration dicate that orJy small loads are felt by the flight is described. The aircraft had flown along primary structure, and that the response fre- the runway at an altitude of less than 1000 ft quencies are in a readily observable range. and was in an accelerated climbing turn when Data show that stresses developed by sonic it passed over the building, but unfortunately, boom overpressure are small. precise information on the height and path of the aircraft and its speed and acceleration in 28. Newberry, C. W., Measuring the Sonic Boom and relation to the building is lacking. There were Its Effect on Buildings, Materials Research and no casualties or injuries because very few work- Standards, Vol. 4, No. 11, November 1964, men were in the building at the time of the pp. 601-611. accident. Damage to glass, curtain walls, suspended ceilings, and roofing was fairly exten- Tests were the made during supersonic flight sive, but the structural steel frame was un- of an aircraft to measure the shock pressures of affected by the boom. the sonic boom and the vibrations produced by them in typical buildings. Shock pressures 32. Wall Splits Bowling Alley Building, Engineering of up to about 5 Ib/ft^ on the ground were re- News-Record, October 29, 1964, p. 15. corded in the central part of the boom area. A two-story brick building partly collapsed Focus zones, where higher pressures were ex- in Ottawa, Ontario when a contractor excavat- pected, did not fall within the measuring posi- ing for a wall next door undermined a footing. tions. Accelerations of roof structures of up to l.Og and roof vibrations of 0.087 in (peak- to-peak) were recoreded. There was evidence 1965 of resonant vibration of parts of the buildings under suitable incident shock conditions, 33. Blakey, F. A., and Beresford, F. D., Stripping of and it appears that such resonant vibration Formwork for Concrete in Buildings in Relation could be harmful at certain discrete points to Structural Design, Civil Engineering Trans- within a boom area should a boom fall on an actions, Australia, Vol. CE7, No. 2, October extensive built-up area. 1965, pp. 92-96.

Analytical determination of the loads which 29. Paris Building Collapse Kills 15, Engineering might be applied to concrete floors of multi- News-Record, January 23, 1964, p. 39. story structures during construction by props The collapse of a 10-story, steel framed apart- from floors above is discussed in this article. ment being erected by a tilt-up method in Paris killed 15 workmen and injured 17. The 34. Low Friction and High Density of Fill Toppled accident occurred as the final 10-story bent Wall, Engineering News-Record, July 8, 1965, swung into position. It went out of control, and pp 40-41. the entire steel frame collapsed. The article discusses the collapse of a 310 ft long section of a 60-ft-high reinforced con- 30. Power, J. K., Some Results of the Oklahoma City crete retaining wall which occurred in 1958. It Sonic Boom Tests, Materials Research and explores the design and workmanship and con- Standards, Vol. 4, No. 11, November 1964, cludes that the coefficient of friction for back- pp. 617-623. fill was underestimated by the designers. When In the sonic boom tests conducted in Okla- one section of the wall collapsed, adjacent sec- homa City in the summer of 1964, no significant tions were overturned because thev were pulled structural damage of any kind was observed forward by the horizontal reinforcement be- in any of the test houses from an exposure of tween the affected sections of the wall. The 1253 sonic booms producing pressures from horizontal reinforcement stripped the cover 1.0 to approximately 4.80 lb/ft-. No wooden from the vertical steel and caused bond failure.

7 35. Ostenfeld, C, Ship Collisions Against Bridge connected with bracing and failure of one Piers, Publications of the International Associa- would cause twisting of neighboring trusses. tion for Bridge and Structural Engineers, Vol. 25, 1965, pp. 233-277. 1966 In recent years characteristic features of 40. Birkeland, P. W., and Birkeland, H. W., Connec- shipping have been steadily increasing traffic tions in Precast Concrete Construction, Journal and a very conspicuous increase of the tonnage of the American Concrete Institute, Vol. 63, of the ships. As a consequence, the risk of ships No. 3, March 1966, 345-367. colliding with bridge piers has increased, and, pp. considering that only a very small number of Requirements for connections in precast con- the existing bridge piers possess masses ex- crete buildings are discussed and examples ceeding the mass of the very large ships built from completed structures where these require- in present days, it is obvious that the conse- ments have been met are given. A time-proven quences to a bridge exposed to a collision of hypothesis explaining shear behavior at con- this nature may have the character of a catas- crete to steel and concrete-to-concrete interfaces trophe. Details of a number of case histories is presented. Examples illustrate beam-to-col- relating to the collision of ships with bridge umn connections using this hypothesis. Sug- piers, etc., detailed calculations of the collision gestions for further study are outlined. of a ship with a lighthouse, an analysis of the effects on a bridge pier of impact produced by 41. Collapse Verdict, Engineering News-Record, May a ship, and some preliminary conclusions for 5. 1966, p. 11. use in design are included. Premature stripping of forms, coupled with 36. Precast Girder Collapse Kills Two, Engineering an overload of reinforcing steel on a recently News-Record, May 13, 1965, p. 29. concreted floor above, was cited by structural engineer Ernest Butts as the cause of the Undermining of an interior column triggered collapse of a reinforced concrete building un- the collapse of 20,000 ft" of precast concrete der construction in Ottawa (see 47). roof framing of a one-story building in Atlanta. The precast double T-sections sat on neoprene 42. Collapses, Failures Take Heavy Toll, Engineering bearing pads and were alternating cantilevers News-Record, May 19, 1966, pp. 30-31. with projected bearing to support interior gir- The article discusses maj or failures occurring ders. recently involving a formwork failure, a steel erection collapse, a roof collapse and a floor 37. Seven Die in Collapse of Italian Apartment. Engi- collapse. Particularly interesting is a collapse neering News-Record, May 20, 1965, p. 24. occurring in Athens during an expansion of a Seven workmen were killed when one wing paper mill. A 4,500 ft^ section of wet concrete of an eight-story apartment building collapsed suddenly collapsed, raining 200 tons of wet on the Italian Riviera. Construction was nearly concrete and reinforcing steel on the first floor completed on the reinforced concrete L-shaped slab, 29 ft below. Designed to carry heavy

structure when it crumbled into a pile of ruins. papermaking machinery, the first floor slab held under the impact. 38. Stanger, R. H. H., Loading Tests of Insitu Joints as Used in the Wates System, Test Reports, 43. Crane Pulled Roof Dome Down, Engineerinj? Ove Arup and Partners, London, October 1965. News-Record, November 17, 1966, p. 66.

300 ft diameter dome had 15 of 24 radial, J Tests on various joints of the Wates build- A trussed steel ribs in place when it collapsed in ing system to determine their resistance to removal of temporary shear loads are reported. Jamaica. Premature falsework supporting the central compression 39. Supermarket Roof Falls on Shoppers, Engineering ring was one unofficial explanation offered at News-Record, May 27, 1965, p. 59. the time. But some engineering detective work later showed that a crane boom had brushed The truss-supported roof of an old super- against one of the ribs just prior to the acci- market building in Brooklyn, suddenly col- dent causing the collapse. lapsed, dropping tons of concrete and steel on the patrons below. It was basically a one-story 44. Cziesielski. E., Berechnung Von Wanden Des structure, with mezzanine offices at the front Gross-Tafelbaues Die Aus Mehreren Einzel- and back of the building. Examining the trusses, wanden Zu Finer Grossen Wandscheibe Zus- building officials discovered severe corrosion ammengeschlossen Werden (Computations for in the encased bottom chord of at least one Large Panel Walls Consisting of Individual truss. A tensile failure of one truss probably Wall Elements Connected into a Large Shear triggered the collapse. The trusses were inter- Wall) Die Bautechnik, March 1966, p. 73.

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Treats analytically the problem of design of Snow and ice totaling an estimated 64 psf large shear walls made up of individual panels. collapsed the timber-framed roof of a curling Contrasts behavior with monolithically cast rink in Sweden. This was probably over three shear walls and outlines proper requirements times the design load of 20 psf. Seven of the for detailing such shear walls comprised of structure's ten 15 ft bays collapsed. large panels. 50. Lewicki, B., Building with Large Prefabricates, 45. Faulty Girder Connection Blamed in Motel Col- American Elsevier Publishing Company, New lapse, Engineering News-Record, December 8, York, N. Y., 1966. 1966, p. 17. A design oriented text treating design, de- A slipped welded connection plate was blamed tailing, and construction of structures made for a structural failure that set off a five-story from assembles of large concrete panels. De reaction at a motel in New Orleans. The con- tailed treatment of joint design with examples. nection plate joined a second floor girder to an Based largely on Russian and Eastern European interior column. Loss of this column set off practice, a considerable variety of test results a chain reaction in upper stories causing 25 and practical experiences are included. Does percent of the building's interior to settle be- not specifically refer to design for progressive tween 8 and 14 in. The structure was approxi- collapse and can be taken as a representative mately 2 years old. sample of Eastern bloc design procedures prior to the Ronan Point occurrance. 46. Feld, J., Reshoring of Concrete Buildings, Engi- neering News-Record, October 6, 1966, p. 33. 51. Marchand, P. E., Report of the Canadian Tech- Faster progress schedules in construction of nical Mission of Prefabricated Concrete Com- tall concrete buildings require a careful analysis ponents in Industrialized Buildings in Europe, of formwork requirements, especially the re- September 2—22, 1966, Department of Indus- shoring of floors after forms are removed for try, Materials Branch, Ottawa, Canada, 1966. reuse. This article outlines a procedure for The introduction of industrialized building determining the number of floors that require systems and techniques has brought about new reshoring assuming that a completed and cured contractural and working relationships between floor can carry 1.33 times its final design load clients, architects, manufacturers and builders. as an interim construction load. It has also given added importance to the ra- 47. Four Groups Investigate Collapse, Engineering tional oirganization of work on the building site. News-Record, April 7, 1966, p. 72. In Europe industrialized building has achieved greater productivity—in terms of the The collapse of three floors of a 12-story value of building per man hour worked—and flat plate reinforced concrete building under greater speed of erection than traditional build- construction in Ottawa occurred one day after ing methods. In this report several European the concreting of the fourth floor. Portions systems and techniques are discussed in detail, of the third floor, which supported the shor- and some indications are given of possible ing for the recently concreted fourth floor, had future trends in the development of industrial- apparently not been reshored. Four Canadian ized buildings in Canada. government agencies are investigating the collapse in which several bays approximately a 52. Natural Gas Pipelines Safe Enough? FPC Has block long sheared away from columns which Doubts, Engineering News-Record, June 23, were left standing (see 41) 1966, pp. 20-21.

48. Gusting Wind Fells Steel Frame, Engineering The Federal Power Commission wants the authority to set federal safety standards for News-Record, June 9, 1966, p. 18. the 150.000 mile interstate network of natural One hundred eighty tons of structural steel gas pipelines. In its report to the Senate Com- ". collapsed like a house of cards when winds merce Committee, the FPC noted that . . the gusting to 50 miles per hour hit the Pittsburgh maximum credible single accident possibility area on May 28. The damage extended to four for a transmission line failure is high, possibly stories of partially erected structural steel in higher than that for railroad, motor car or part of Duquesne University's new science air transportation." It also pointed out that building under construction. The construction 28 percent of pipeline failures was caused by was guyed and bolts had been inserted in every damage from earth moving equipment. connection but connections had not been completed. 53. Porl, M. K. (Translator), Common Directives for the Agrement of Building Systems with 49. Ice and Snow End Curlins: Match. Engineering Large and Heavy Prefabricated Panels (Direc- News-Record, Feb. 24, 1966, p. 17. tives commones pour I'agrement des precedes .

de construction par grands panneaux lourds sulted in rotation of a steel I-beam ring seg-

prefabriques) , Union Europeene Pour I'Agre- ment about its longitudinal axis. All twelve ment Techniques Dans La Construction, Liv- segments fell when the tension ring connection raison 80, June 1966. gave way.

Detailed requirements for structural safety, 58. Snow, Wind Triggered Dome Collapse, Engineer- stability, hability, and durability of large panel ing News-Record, May 19, 1966, p. 31. structures of precast concrete for international A 170 ft diameter wood lamella dome col- acceptance under the agrement system. Con- lapsed March 3, 1966. An investigator blamed tains standards for joint and tie beam design snow load and wind for the collapse and also as well as overall stability. Contains both declared that he believed the dome was im- performance requirements and outlines of ac- properly designed and fabricated. ceptable tests and calculation procedures for meeting standards. 59. Somerville, G., and Burhouse, P., Tests on Joints Between Precast Concrete Members, Proceed- 54. Quadruple Floor Overload Blamed in Building ings, Symposium on Industrialized Building Failure, Engineering News-Record, February 3, and the Structural Engineer, London, 1966, 1966, p. 17. pp. 125-142. Overloading was blamed for the floor failure A well-documented review of experimental of a factory building which triggered a col- studies on joints between precast concrete lapse following a falling domino pattern. A sec- members (i.e., column-coluirm, beam-column, tion of the fifth floor gave way, dropping ma- beam-beam joints, and joints in large-panel chinery and materials which successively caused structures ) , with detailed tabulations of test the failure of portions of the fourth and third results and drawings of test specimens. A bib- floors. Building officials estimated the top floor liography lists 73 references to such studies. was carrying an overload four times the posted 120 psf capacity (see 56) 60. Sports Hall Roof Collapses, Engineering News- Record, January 6, 1966, p. 15. 55. Russoff, B. B., Transportation and Erection Prob- lems, Proceedings, Symposium on Industrialized Swedish authorities are investigating the Building and the Structural Ejigineer, London, collapsed. A possible cause of failure was in- 1966, pp. 117-124. type of steel-reinforced, laminated wood I- beam. One of the two brick end walls also The influence on structural design and de- collapsed. A posible cause of failure was in- tailing of transportation, handling and erec- sufficient bond of the reinforcing bars with tion considerations for precast concrete build- laminated wood 80 ft span girders. Collapse ing elements is shown by describing how con- of the brick bearing wall resulted in total col- struction stresses are induced in relation to the lapse of all roof members. size and shape of the elements. The use of manufacturing equipment and erection cranes is described by examples. 1967

56. Sheared Bolts Caused Collapse, Engineering News- 61. Arthur D. Little Inc., Public Safety and Gas Dis- tribution, Research Report prepared for the Record, February 24, 1966, p. 18. American Gas Association, Weishington, D.C., Century-old % in diameter bolts, which con- December 1967. nected an eccentric bracket to the cap of a cast of safety pro- iron column, failed at shearing stress nearly The report defines the scope twice the ultimate shearing capacity of carbon lems associated with the distribution of utility through 1964. It is steels manufactured during the Civil War. This gas for the period of 1957 within was part of the New York City Building Depart- based on a study of gas leak incidents in 140 ment's analysis of the three floor progressive the gas distribution industry which 83.3 per- collanse of the 100-vear-o'd Manhatten factory companies and systems, representing all gas distribution meters in the U.S. building (see 54). In addition to severe over- cent of findings include the loading, an unauthorized alteration to the an- participated. Principal location, number incidents, type, j tique structure contributed to the collapse. number of fatalities an assessment of the causes, of and j 57. Shell Roof Topples in Atlanta, Engineering News- Comparisons were made between the safety

Record, September 1, 1966, p. 12. record of the gas distribution industry and that of other utility industries, railways, air- The 120 ton precast concrete roof of a chapel lines, eta imder construction collapsed in Atlanta. Ob- servers reported the failure of a weld in the 62. Collapse May Never Be Solved, Engineering News- peripheral steel tension ring that allegedly re- Record, December 21, 1967, p. 69.

10 The article reviews aspects of the collapse of dicates the need for careful consideration of the three main spans of the Point Pleasant- design parameters such as live load to dead Gallipolis Bridge on December 15, 1967. It load ratios in deciding when to strip forms. was the first eyebar suspension bridge in the U.S. in which the eyebars formed the top 68. Recommandations Internationales Unifiees Pour chords of the stiffening trusses in both the Le Calcul Et L'Execution Des Constructions En main and anchor spans. The bridge design, the Panneaux Assembles De Grand Format (Inter- collapse sequence and the possible causes are national Recommendations for the Design and also discussed. Construction of Large-Panel Structures ) , Co- mite Europeen du Beton, Bulletin No. 60, Paris, Explosives 63. and Demohtions, U.S. Department of April 1967, English translation by C. V. Amero- the Field Armv, Manual, FM 5-25, Washington, gen. Cement and Concrete Association, No. 137, D. C, May 1967. London, July 1968.

Information is provided on the type, charac- A comprehensive set of design rules with teristics, and uses of explosives and auxiliary commentary for large panel structures de- equipment. Preparation, placement, and firing veloped by CEB in 1966. Apphcable to struc- of charges is discussed. Charge calculation for- tures with floor or waU panels and with various mulas are provided. types of joints. Specifies design rules for individual members, joints and tie beams. Prom- 64. Five Die in New York Collapse, Engineering ulgated prior to Ronan Point collapse, it News-Record, February 2, 1967, p. 15. treats provisions for prevention of progressive Five workmen were killed when an ancient collapse only indirectly. It does require sub- brickbearing wall building, standing on the stantial continuity precautions which might edge of an excavation for a 40 story office have mitigated Ronan Point damage. tower, collapsed. Vibration caused by the power shovel work apparently caused the build- 69. Robinson, J. R., Calcul Des Constructions Par ing to give way. The building had been a one- Panneaux Assembles A Joints Verticaux Elas- story blacksmith shop in the 1870's and was a tiques Plastiques (Design of Precast Panel four-story apartment building at the time of Structures Assembled with Elasto plastic Ver- collapse. tical Joints), Comite Europeen du Beton Bulle- tin d'Information, No. 60, April 1967, pp. 173- 65. Guide Pratique Des Installations De Gaz (Prac- 197. tical Guide for Gas Installations), Gas of France, et al., Paris, Joint Government decree Considers the effect of elastic and plastic of October 15, 1962, modified and complete capacity of joints on precast panel structures. March 17, 1967. Indicates the advantages of ductility in such joints and suggests procedures for insuring Distribution of gas and detailed requirements reasonably ductile behavior of the joints be- for installation in buildings are covered. tween panels.

66. Newberry, C. W., The Response of Buildings to 70. Secrecy Veils Bridge Collapse, Enginering News- Sonic Boom, Sound Vibration, Vol. 6, No. 3, Record, December 14, 1967, p. 27. Ministry of Public Building and Works, Build- ing; Research Station; England, 1967, pp. 406- A five-span reinforced concrete beam and 418. slab structure over a deep gorge near Mexico City collapsed, killing an estimated 30 work- Some experimental observations of one exci- men. Three central spans and 72 ft tation of building structures by sonic boom (72, 102, long) and two tall, slender piers collapsed are reported. The question of coincidences be- into the gorge taking with them tons of steel tween sonic boom periods (including reflec- tubing falsework. A commission of eight en- tions) and natural periods of building struc- gineers is investigating the cause of the collapse. tures is particularly discussed. Apparently the falsework was being dismantled at the time of collapse. 67. Proposed Revision of ACI 347-63 : Recommended Practice for Concrete Formwork, ACI Com- mittee 347 (W. R. Waugh, Chairman), Journal 71. Short, W. D., Structural Collapses During Erec- of the American Concrete Institute, Proceed- tion or Demolition, Proceedings, Institute of Civil Engineers, London, Vol. ings, Vol. 64, No. 7, July 1967, pp. 337-373. 36, March 1967, pp. 507-522. Comprehensive recommendations for design and construction of concrete formwork covering The paper describes buildings and civil en- the procedures, materials and structural types gineering structures which have collapsed in with extensive discussion of construction loading recent years during erection or demolition. effects of reshoring multi-story structures. In- These accidents were costly and often resulted

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in deaths or injuries. They could have been forms for the 120 X 200 ft building were sup- prevented if there had been a wider knowledge ported by 4X4 in wood jackposts resting of the causes of failure. on the completed second floor. When the posts gave, deck forms holding concrete for

72. Steel at . . . Span Mid-Channel Nose-Dives Into a 40X120 ft section of the building fell, col- the River, Engineering News-Record, November lapsing the second floor to the street level. 16, 1967, p. 19. 77. Council, K. F., and Smith R. B., Analysis of A $14-million, 1,600 ft long, high-level steel Causes and Determination of Possible Means highway bridge collapsed during erection kill- of Prevention of External Damage to Pipe- ing at least 20 workmen. Officials at the scene lines, American Gas Association, Inc., Catalog speculated that recent heavy rains had under- No. L3OO05, New York, 1968. mined one of the piers causing it to settle. As a result, the temporary cables supporting the in- An analysis of pipeline failures for the period clined legs of the main-span frame snapped, 1950 through 1965 revealed that failures triggering the collapse of the entire structure. caused through the operation of mechanical equipment such as graders, bulldozers, and ditchers, appeared to be increasing slightly, 1968 while failures from all other causes were de- creasing. A program was carried out to de- 73. Anatomy of Collapse, Engineering, London, No- termine the causes and to develop recommen- vember 15, 1968, p. 707. dations to reduce the incidence of these "ex- Extracts from the official report of inquiry ternally caused" failures. into the progressive collapse of a multi-story 78. Enquiry into the Accident at Canning Town, apartment building (Ronan Point) in London of the Month, Concrete, London, Vol. built entirely with industrialized (prefabri- News 2, No. June 1968, 228. cated) floors and bearing walls are included in 6, p.

the article. Initial news note summarizing the main effect of the accident in the Ronan Point apart- 74. Bridge Failure Triggers off Studies, Engineering ment building, speculating on possible cause News-Record, January 1968, 18-19. 4, pp. and announcing panel for the Ministry inquiry. The task of removing bridge parts, vehicles 79. Feld, Construction Failure, John Wiley and and bodies from the icy waters of the Ohio J., Sons, Inc., New York, 1968. River at the site of last month's collapse of the 40 year old, eyebar suspension bridge between A comprehensive treatment of causes of con- Point Pleasant and Gallipolis is nearly com- struction failures citing large numbers of re- pleted. Investigations into the cause of the ported construction failures and illustrating disaster are just getting underway by a federal the more frequent tyi>es of failures occurring panel and The West Virginia Road Commission, in the United States. Substantial treatment is which owns the bridge (see 62) given to failure from man-made-causes and natural disasters as well as failure of formwork 75. Collapse May Cause Law Change, Engineering and temporary structures. The book is well illus- News-Record, November 1968, p. 33. 7, trated and contains many thoughtful recom- The total collapse of an almost completed mendations for reduction of construction four-story reinforced concrete building in Ma- failures. laysia occurred while workmen were finishing 80. Flats Constructed with Precast Concrete Panels. jobs such as door and window adjustments, Appraisal and Strengthening of Existing High touch-up painting and hardware checking. Un- Blocks: Design of New Blocks, Ministry of official sources attribute the collapse to a con- Housing and Local Government, Circular 62/ crete low in cement and high in sand. New 68, London, England, November 15, 1968. building regulations may result from a gov- ernmental inquiry to determine the possible In this circular to all Local Authorities the cause. Minister of Housing impressed most strongly on Local Authorities that all blocks over six 76. Concrete Pour Collapses Form, Engineering News- stories built of large precast concrete panels Record, June 13, 1968, p. 25. must be appraised for resistance to progressive The collapse of wood shores during a con- collapse, wind and fire and be strengthened, in crete pour for a 12-story building in Arling- accordance with the Technical Appendix. The ton, Va., killed three workers and injured 29. standards set out in the appendix were ordered Workers had poured approximately 185 yd^ of applied to new design. This circular applied concrete on the third deck of plywood forms to all existing and to new construction "pend- containing steel reinforcement bars. The deck ing the revision of Building Regulations and

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Codes of Practice." Briefly the circular laid on the 18lh floor of Ronan Point. The explosion down two alternative methods of avoiding pro- blew out the concrete panels forming part of gressive collapse: "Method A—by providing the load-bearing flank for gable) wall. As a alternative of paths support to carry the load, consequence, removal of thi.s wall precipitated assuming the removal of a critical section of the collapse of the southeast corner above the the load bearing wells," and "Method B—by 18th floor including both the bedrooms and providing a form of construction of such stiff- living rooms. The weight of this portion of the ness and continuity as to ensure the stability of building, as it fell, caused a progressive col- the building against forces liable to damage the lapse of the remaining southeast corner flats load supporting members." Under Method A, down to the level of the cast-in-place concrete a series of arbitrary rules were laid down as a podium of the block. The report deals with the basis of acceptance, whereas under Method B reasons for the collapse, the lessons learned the intent was that the Engineer should assess from the disaster and contains recommenda- the members' ability to sustain the load de- tions for design of tall buildings. fined (for discussion see 86) 85. Not Enough Bracing, Engineering News-Record, 81. Gas Turned Off, Engineering News-Record, June 27, 1968, p. 7. August 22, 1968, p. 17. Insufficient lateral and diagonal bracing of The British government has told local gov- 3X4 in wood jack posts caused the collapse ernment authorities to cut off gas supplies to of two floors of an Arlington office building some tall prefabricated apartment buildings as during a concrete pour (see 76). Another con- a result of the Ronan Point collapse. interim An tributing factor was that permanent steel gir- report from a tribunal investigating the col- ders to support two floors above a driveway lapse is also discussed. had not been placed prior to the collapse.

82. Godfrey, K. A., Technology in New Low-Income 86. Notes for Guidance Which May Assist in the Housing, Civil Engineering, January 1968, pp. Interpretation of Appendix 1 of the Ministry 43-55. of Housing and Local Goverrmient Circular Rehabilitation of decaying urban areas has 62/68. RP/68/02, The Institution of Struc- tural Engineers, London, December 1968. become a national goal. Part of the answer to this demand may be new technology meaning The Institution of Structural Engineers con- advanced production techniques. Author then sulted the Panel of Advisors appointed by the describes prefabrication and the five new apart- Ministry and the comments and explanations ment housing systems. received on Circular 62/68 (see 80) are con- 83. Goffin, H., Grossformatige Wand-Und Decken- tained in RP/62/02. tafeln Fur Den Hock-Und Industriebau (Large- 87. Reese, L. C, and Matlock, H., Structural Damage sized Wall-and Ceiling Panels for Building from Tsunami at Hilo, Hawaii, Journal of the Construction and Industrialized Construction), Hydraulics Division, ASCE, Vol. 94, No. HY4, Betonstein-Zeitung, Weisbaden, June 1968, pp. 280-287. July 1968, pp. 961-982.

This article describes, by means of examples, A study of the wave characteristics and a the problems resulting from the supervision of survey of structural damage to onshore struc- works and from the trend to guarantee high tures due to the destructive Tsunami which quality for prefabrication. Details are given stuck Hilo, Hawaii in May 1960. of basic legal data, such as, building provisions and technical construction regulations as well 88. Repercussions from the Failure of a Sub-Standard as the various construction types and methods. Brass-Nut. Editorial Comment, Concrete. Lon- Also being specified are volume stability, disk don, Vol. 2, No. 12, December 1968, pp. 480- effects, bearing points and panel points, as well 481. as tension-proof joints. Further physical as- General comments are presented on the im- pects of construction, joints in sandwich-type plications of Ronan Point disaster. The main slabs, and prefabrication in mining subsidence point being one common factor in structural regions are described. failures is an absence of that fundamental knowledge of how a particular structure is go- 84. Griffiths, H., Pugsley, A., and Saunders, 0.. Re- ing to behave when it is approaching the limits port of the Inquiry into the Collapse of Flats of its stability and strength. The author states at Ronan Point, Canning Town, Her Majesty's that such an understanding is the verv' quin- Stationery Office, London, England, 1968. tessence of the art of the engineer, and it can At about 6:00 a.m. on 16 May 1968 a gas never be replaced, only assisted by codes or explosion occurred in the southeast corner flat regulations. Thus, there is need for constant

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review of old codes to match new building fabricated panels which discusses basin prin- techniques. ciples, planning (of structural layout), workmanship and erection, all in general terms. It 89. Report of British Collapse Gtes Building Code contains general recommendations on design Flaws, Engineering News-Record, November to avoid progressive collapse. 21, 1968, p. 23. 94. Systems Built Apartments Collapse, Engineering This article reports that loopholes in Brit- News-Record, May 23, 1968, p. 54. ain's building codes possibly contributed to the progressive collapse of all 24 floors on one The article reports the collapse of a new, 24- corner of a 24-storv London apartment house story prefabricated apartment house in Lon- (see 94) don (Ronan Point). The collapse is attributed to a gas explosion near the top that blew out 90. Ronan Point Inquiry, News of the Month, Con- an exterior, one-story high bearing wall, trig- crete, London, Volume 2, No. 9, September gering a chain reaction that collapsed walls 351. 1968, p. and floor slabs on all 24 stories.

Contains verbatim copy of text of interim advisory letter from the chairman of the Ro- 1969 nan Point collapse inquiry panel to the Min- 95. Alexander, S. and Hambly, E. C, Design of ister of Housing briefing him on the probable J., Domestic Buildings to Withstand Gaseous Ex- causes of the collapse, and suggesting that all plosions, Ove Arup and Partners, Consulting "system" built high rise apartment buildings Engineers, London, England, May 1969. be examined for susceptibility to "progressive collapse." It suggests gas be turned off in any Various means of reducing the consequences susceptible units and a strengthening program of gas explosions in buildings such as, com- undertaken. The article also contains detailed plete removal of the explosive source, force excerpts from the Ministry letter to local gov- ventilation, and control of the maximum flow ernments giving advice on immediate measures of gas from the supply are discussed. A quali- to be taken. tative description of the nature of a gas explosion in terms of gas/ air mixture, presence of 91. The Ronan Point Inquiry and the Significance of venting, pressure rise, turbulence, and other Structural Joints, Editorial Comment, Concrete, related parameters, is presented. A method of London, Vol. 2, No. 7, September 1968, p. 348. analysis of structures subjected to these dynamic loads is provided. Editorial commenting on the letter of the Chairman of the Panel of Inquiry to the 96. Balcony Fails During Construction, Engineering Ministry which had stated preliminary panel News-Record, August 7, 1969, p. 37. findings concerning the Ronan Point collapse. The editorial points out progressive collapse A 26X6 ft balcony at the 18th floor of a 22- is not a new phenomena having occurred dur- story reinforced concrete apartment building ing construction of Gothic cathedrals during collapsed in Buenos Aires. The falling balcony medieval ages and that "system building" is ripped off those on the next three lower floors. not the only class of construction with potential for such type of collapse. 97. Building Regulations: The Fifth Amendment and the Freedom to Design, Editorial Comment, 92. The Structural Behavior of Ronan Point, Concrete, Concrete, London, Vol. 3, No. 9, September London, Vol. 2, No. 12, December 1968, pp. 1969, pp. 343-344. 488-491. A critical and thoughtul evaluation of the This article reports, almost verbatim, those Report of the Panel of Inquiry on the Ronan sections of the report of the tribunal of in- Point collapse and the subsequent amendments quiry into the partial collapse of Ronan Point to the Building Regulations. The editorial ad- vocates placing responsibility with the design that describe the design of the block, how it in behaved structurally at the time of the collapse, engineers and minimizing specific provisions regulations. article also claims the and how it would behave under severe wind building The loads (see 84) Ronan Point design never conormed to existing building regulations. 93. Structural Stability and the Prevention of Pro- gressive Collaose, RP/68/01, The Institution 98. Bygningsreglement for Kobstaederne Og Landet. of Structural Engineers, London, England, De- Tillaey Nr. 3. Midlertidige Krav Til Bygningers cember 1968. Stabilitet. (Building regulations for urban and rural areas. Amendment No. 3 Provisional Re- Recommendations concerned primarily with quirements for Stability of Buildings), Den- large residential buildings comprised of pre- mark, February 1969.

14 Two minimum requirements are stated for Institution of Structural Engineers' com- building with more than 6 stories; either (a) ments on the proposed (Fifth) Amendment to or (b) must be satisfied: the Building Regulations. (a) in every room limited by an outer wall, 102. Comparison of the Relative Safety of Gas and a floor and/or the outer wall should be Electric Appliances, Shell International Gas able to fail without causing destruction Limited, Report No. SIG 69/9, London, of any floors other than those limiting the room. October 1969.

(b) every normal section in a load carrying A comparison is given of potential and ex- outer wall and in a floor shall be de- isting fire hazards related to the use of gas signed for a tensile force of 2 Kgf/m or electric utilities in Great Britain.

using allowable stresses . . . The necessary reinforcement may be placed in 103. Despeyroux, J., L'Effondrement De LTmmeuble the elements and/or in the joints be- De Ronan Point Et Ses Consequences En tween the elements. Matiere De Codification (The Collapse of the Ronan Point Building and its Consequences 99. Coles, B. C, and Hamilton, W. A., Repetitive Dy- with Regard to Code Writing), Annales de namic Loading on Pretensioned Prestressed ITnstitut Technique du Batiment et des Tra- Beams, Journal of the American Concrete In- vaux Publics, No. 263, November 1969, pp. stitute, Proceedings, Vol. 66, No. 9, September 1800-1803. 1969, pp. 745-747. The author points out that well prior to the A laboratory investigation of the dynamic Ronan Point collapse the CEB regulations behavior and the magnitude of the reduction spoke of panel structures as a "house of cards" in load carrying capacity of beams subjected and called for mechanically continuous net- to several repetitions of dynamic load (simu- works of reinforcement to prevent progressive lated blast-type loading) shows that the calcu- collapse. Many structures have been built in lated ultimate static load is a satisfactory de- contempt of these regulations. He regrets that sign criterion and that bond failure does not the official Ronan Point inquiry report did appear to be a critical factor. not specifically point out that the destroyed building violated these CEB principles and Collins, al.. 100. A. R., et The Implications of the doubts that if these principles had been fol- Report of the Inquiry into the Collapse of lowed that the progressive collapse would have Flats at Ronan Point, Canning Town, The occurred. Commenting on the British Fifth Structural Engineer, London, Vol. 47, No. 7, Amendment, he indicates the 5 psi pressure July 1969. as excessive and the alternate path method as being too confusing and complex. A series of discussion are presented that deal with the implications of the Report of 104. Despeyroux, J., Recommandations Internation- Inquiry into the Collapse of Flats at Ronan ales Unifiees Pour le Calcul et L'Execution Point, Canning Town (see 84). The Tribunal Des Structures En Panneaux Assembles De inquired into the circumstances affecting the Grand Format (Unified International Recom- progressive collapse of the flats on May 16, to mendations for the Calculation and Construc- ascertain the cause or causes, and to consider tion of Large Panel Structures), Comite the implications of the findings, and to make Europeen du Beton Commission XIII. Struc- recommendations. of the longer-term Some ture en panneaux (Panel Structures), 1969. implications of what the Tribunal had to say have hardly been discussed. There was the Contains basic design philosophy for large comment in the broadest sense that archi- panel structures. Points out the basic dangers tects and engineers had been found wanting. of progressive collapse and suggests proper There was the stricture that, unless British design and detailing philosophies to minimize Standards and Codes of Practice were kept risk. Suggests that CEB 1964 regulations re- up to date, false standards mi2;ht be set up quire additional factors of safety in bearing which would lull those concerned with new wall type structures. forms of construction into a dangerous com- placency. 105. A Failure of the Organizational Svstem. News of the Month, Concrete, London, Vol. 3, No. 6, 101. Comments of the Institution of Structural Engi- June 1969, P. 215. neers to the Ministry of Housing and Local Government on the Proposed (Fifth) Amend- Summarized remarks of the President of ments to the Building Regulations, The Struc- the Institute of Structural Engineers that tural Engineer, London, Vol. 46, No. 9, Sep- failure of Ronan Point was essentially a tember 1969, p. 376. failure of an organizational system that relied

15 .

too much on regulations and blurred the re- 110. Classman. A., Structural Failures, International sponsibility of the design professionals. Civil Engineering, London, No. 5, May 1969, pp. 216-223. 106. Fieldhouse Collapse, Engineering News-Record, March 6, 1969, p. 7. The causes of failure may be placed in two categories. The first category covers cases Eighteen long-span steel joists partially where the cause of failure is clear from the framing a cross-shaped, 405X322 ft field- beginning. The second category covers cases house at the University of Dayton, Ohio, of cracking or building coUapse due to unde- collapsed. The 8 ft deep, 8 ft c-c joists termined causes which must be clarified. The spanned 186 ft to jack trusses spanning 48 subject is discussed under the following head- ft between column bays. Cause of the col- ings: characteristics of investigations; failure lapse is not yet determined. due to faulty design; failure due to calcula- tional faults; damages caused by settlement of 107. Fifty-three Killed in Building Collapse, Engi- foundations and soil action; failure due to influ- neering News-Record, June 19, 1969 p. 75. overload; failure due to temperature ence; failure due to shrinkage and creep; and A three-day old reinforced concrete res- failure due to fire. taurant near Madrid collapsed killing 53 persons and injuring 145. Construction of the 111. Guidance on the Design of Domestic Accom- two-story structure was rushed, and reports modation in Load-Bearing Brickwork and said that some of the poured concrete was not Blockwork to Avoid Progressive Collapse Fol- cured. The collapse began when the steel sup- lowing An Internal Explosion, RP/68/03, The ported slate roof suddenly gave way. Seconds Institution of Structural Engineers, London, later, a portion of the ground floor caved in, England, May 1969. dropping 250 persons into the basement. In a series of thundering cave-ins, the entire Guidance is given for the design of load- structure fell in. bearing brickwork structures to withstand an appropriate nominal static pressure, repre- 108. Firnkas, Sepp, Book Review of Report on the senting a possible internal gas explosion, to- Inquiry into the Collapse of Flats at Ronan gether with the additional ability to bridge Point, Canning Town, England, Civil Engi- over severe structural damage arising from neering—American-Society of Civil Engineers, pressure in excess of this nominal value. November 1969, p. 96. 112. Hanson. K. and Olesen, S. Failure Load and A reasonably comprehensive review of the Failure Mechanism of Keyed Shear Joints. report of the commission of inquiry into the Test Results II, Danmarks Ingeniorakademi Ronan Point disaster. Contains several of the Bygningsafdelinsen (Danish Academy of En- key figures and photos. The author points out gineerine Building Department), Report No. important differences between U.S. and Euro- 69/22. Copenhagen, June 1969. pean philosophy regarding joints as regards ductility and implies U.S. practice would be The results of tests which have been made considerably more conservative than that for the determination of the strength and stiff- found in Ronan Point (see 84) ness of vertical, keyed shear joints between wall elements of pre-fabricated concrete are effect of 109. Firnkas, S., Concrete Panel Building System: described. The study includes the Progressive Collapse Analyzed, Civil Engineer- strength of joint concrete, reinforcement ra- ing—American Society of Civil Engineers, No- tio, reinforcement in deck joint versus hair- reinforcement in the wall joint, shrinkage vember 1969, pp. 60-62. pin in the wall joint and repeated loadings above of the The coUapse of a flat at Ronan Point is re- cracking load with changing direction viewed and an alternate path design philoso- shear forces. phy is suggested by the author. The paper points out that Ronan Point's structural sys- 113. Haseltine, B. A., and Thomas. K., Load-Bearing tem relied on gravity and friction to develop Brickwork-Design for Accidental Forces. Clay strength in the joints. This proved inadequate Products Technical Bureau, Technical Note 6, and when an explosion occurred in a corner Vol. 2, London, July 1969. apartment, all the units above collapsed progressively to the ground. The author suggests This Technical Note is intended to assist that joints must be quasi-monolithic and be engineers designing load bearing brickwork able to handle both tensile and compressive structures to comply with the Institution of loads. Structural Engineers document Guidance on

16 the Design of Domestic Accommodation in found for locating "critical" elements in a Load-bearing Brickwork and Blockwork to structure as well as developing design methods Avoid Collapse Following an Internal Explo- for a "fail-safe" design. sion. Only buildings containing domestic residential accommodations are covered. 117. Lugez, J., Zarzvcki, A., Influence Des Joints Horizontaux Sur La Resistance Des Elements 114. Large Panel Structures, Editorial Comment, Con- Prefabriques De Murs Porteurs (Influence of crete, London, Vol. 3, No. 6, June 1969, p. Horizontal Joints on the Resistance of Pre- 213. fabricated Panel Elements of Bearing Walls), Cahiers du Centre Scientifique et Technique Reports on meetings of the Institution of du Batiment, No. 103, Paris. October 1969. Structural Engineers and the Concrete Society approximately one year after the Ronan Point The effects of horizontal joints on the explosion (see 115). Editorial decries treat- strength of prefabricated elements are de- ment of the problem in static and not dynamic scribed. The analysis conducted for various terms and is critical of the alternate path of parameters is based on observations of support concept. cracking and collapse phenomena, on a comparison of test results and, wherever possible, 115. Large Panel Structures, Concrete, London, Vol. on simpUfied theoretical considerations. 3, No. 7, July 1969, p. 262. 118. Mast. R. F., Auxiliary Reinforcement in Con- A short synopsis is given on the main points crete Connections, American Society of Civil brought out at a meeting held by the Con- Engineers, Journal of the Structural Divi- crete Society to discuss the paper Large-panel sion, June 1969. Structures—Notes on the Draft Addendum 1 A method is presented for the design of aux- to CP 116 (1965) , by A. Short and J. R. Miles. iliary reinforcement in concrete connections. One main point was almost unanimous con- This is based demnation of the arbitrary design approaches method on a physical model, which may be judiciously used to extrapolate put forward in the appendix to the Ministry's designs into regions not covered by previous circular 62/68. Further criticism was di- tests. Rather than attempting to predict the rected upon the alternative path or "fail-safe" nature of cracking in a concrete connection, approach and the static pressure design of cracking in an unfavorable manner is as- 5 psi. Suggestions were that: an explosion in sumed. Reinforcement is then provided, in ac- a building was a problem of the dynamic re- cordance with the shear-friction hypothesis, sponse of a structure and not one of statics to assure that this cracking will not lead to and; there should be more emphasis on pro- premature failure. grams for test information.

119. Mr. Hubert Bennett on Ronan Point. News of 116. Ligtenberg, F. K., Vailigheid En Catastrofen the Month, Concrete, London, Vol. 3, No. 6, (Structural Safety and Catastrophic Events), June 1969, p. 215. TNO-Nieuws, 24, Amsterdam, 1969. Summary of a speech by a prominent The customary methods for calculating the British architect which indicated that Ronan strength of structures start from the assump- Point was a unique occurrence and pointed tion that a factor of safety between the out that application of new standards to guard strength of a structure and the given loads against a repetition would cost millions of furnish a sufficient guarantee that abnormal pounds in England alone. loads can be sustained. Statistical considerations combining the strength of the ma- 120. Norme Per II Calcolo E La Contruzione Di terials, the type of the structure, the mag- Structure A Grandi Panelli. Ministerio del nitude of the loads and the frequency of the Lavorio Pubblici, Rome, 1969. occurrence of abnormal loads like fire, ex- Italian code of practice for structures manu- plosions, collisions, etc., show that this as- factured from large panels. sumption is justified for small structures consisting of only a limited number of elements. 121. Paddleford. D. F.. Characteristics of Tornado A structure of greater dimensions, however, Generated Missiles, Westinghouse Electric is not allowed to collapse as a whole if one of Corporation. Nuclear Energv Systems. Pitts- the elements fails. In this case, as well as the burgh, Pennsylvania, April 1969. probability of a disaster, the magnitude of a disaster increases with the magnitude of the To check or assess the effects of tornado- structure. The magnification of scale which induced missiles on a plant design it is neces- is a marked tendency in modern buildings sary to assume a spectrum of missile sizes and makes it necessary to consider these aspects velocities that could accompany a tornado. seriously. It is necessary that methods be The wind field of a tornado has been described

17 using relations appearing in the technical A well illustrated report of the effects of literature and solutions of the trajectory of a local overloads such as explosions and vehic- spectrum of missiles have been obtained ular impacts on stability of structures. In- numerically for a number of cases. The re- cludes a very thorough classification of vari- sultant size-velocity relationship for missiles ous types of local overloads. generated by a 300-mph tornado is given graphically, and these results to are used 127. Rasbash, D. J., Explosions in Domestic Struc- obtain the velocities of typical objects that tures; Part 1: The Relief of Gas and Vapour could be postulated as potential tornado mis- Explosions in Domestic Structures, The Struc- sile sources. tural Engineer, Vol. 47, No. 10, October 1969, pp. 404^408. 122. Pipeline Accidents Report. Low-Pressure Natural Gas Distribution System, Gary, Indiana, Na- A quantitative approach to estimating the tional Transportation Safety Board, Wash- pressures that may develop in domestic struc- ington, D.C., June 1969. tures during gas and vapour explosions is

A gas line failure in Gary, Indiana is in- suggested which takes account of the influence vestigated and recommendations are made by of potential explosion relief, such as external the investigating Safety Board. windows, doors, etc., of a structure similar to that of the London industrialized apartment 123. Precast Concrete Garage Collapses, Engineering building (Ronan Point), which collapsed par- News-Record, May 22, 1969, p. 51. tially due to an explosion.

A majority of the precast concrete framing 128. Reporting Can Prevent Failure, Editorial. Engi- components for a five-story garage collapsed neering News-Record, February 1969, in Las Vegas injuring three workmen. Ac- 6, p. 186. cording to a job spokesman, something a]> parently gave way on the level beneath the Comments on the importance of reporting fifth level causing the slabs and girders on the structural failures, which lead to advances in fourth and fifth levels to fall on the floors the practice of design and construction below. This triggered a chain reaction to the ground. methods, are contained in this editorial. The Ronan Point Inquiry is mentioned as an 124. Proposed Amendments to the Building Regula- example. The editorial states that a 1967 tions 1965, Ministry of Housing and Local CEB report had specifically mentioned the Government, London, England, May 30, 1969. danger of progressive collapse in large panel concrete construction, but had not been widely The proposed amendments to include pro- disseminated. visions dealing with progressive collapse constitute the first installment of the Ministry of 129. Robinson, J. R.. Observation Sur Les Con- Housing and Local Government's proposals clusions Du Rapport De La Commission for amendment of the building regulations in D'Enquete De Ronan Point (Observation on the light of the recommendations of the Tri- the Conclusion of the Report of the Inquiry bunal of Inquiry into the collapse of flats at Commission on Ronan Point), Annaies de Ronan Point. rinstitut Technique du Batiment et des Tra- vaux Publics No. 263, November 1969, 125. Rapport Era Dansk Ingeniorforenings Fragards pp. 1797-1799. Udvalg For Bygningers Stabilitet Ved Lokal Overpavirkning (Report of the Committee on This article presents approximate calcula- Stability of Buildings Subject to Local Unpre- tions which lead the author to a conclusion dictable Additional and/or Accidental Loads that the Ronan Point apartment could not and Effects), Expert Council of the Danish withstand pressures greater than a static Society of Engineers, May 1, 1969 (in Dan- equivalent of approximately 1^/2 psi- It points ish). out that the risk of progressive collapse has Explosions, vehicular impact and other local been present in high-rise masonry bearing overloads are described. wall buildings for a long time, but has not generally been considered. The author feels 126. Rapport Era Dansk Ingejorforenings Fragads that the "alternate path" criteria is too Udvalg For Bygningers Stabilitet Ved Lokal severe and suggests engineers have long de- Overpavirkning (Report from the Danish signed statically determinate structures which Engineering Association Professional Com- have no alternate path (metal trusses, for ex- mittee for the Stability of Buildings under ample). He suggests simple principles for Local Overloads), Dansk Ingerj orforening, design of bearing wall structures in which Kopenhamm, 1969. venting principles would be considered.

18 :

130. Rodin, J., Statistical Design Against Progressive mendations for large panel structures and Collapse, The Consulting Engineer, London, states it was published in CEB Bulletin 60 in August 1969. Paris in French in July 1967. States exam-

ination of plans of Ronan Point show it did Safety is related to both the risk and struc- not meet the requirements of the CEB prin- tural consequence of particular events relevant ciples. Points out the Algiers building shown to the satisfactory behavior of structures. Ab- in the Ronan Point inquiry report did meet solute safety against all possible conditions these requirements and survived a severe ex- and hazards can never be achieved, thus the plosion. States detailed examination of the problem is one of reducing the risk. By as- Ronan Point incident did not result in any sessing the statistics of all foreseeable hazards changes to the CEB document. This paper de- in terms of risk, coupled with structural con- tails the authors opinions of the shortcomings sequences, a uniform level of safety can be of the new British recommendations and is achieved, acceptable safety at an acceptable extremely critical of the "alternate path" con- cost. The acceptable risk of life should be de- cept. cided by politicians and representatives of the

community at large, not the structural engi- 134. Short, A., and Miles, J. R., An Introduction to neer. The design against progressive collapse the New Code of Practice for Large Panel can be done in three ways Construction, Concrete, London, Vol. 3, No. (a) eliminate the hazards which may lead 4, April 1969, pp. 121-123. to local failure or reduce the risk to review of the new provisions for large an acceptable value. A panel construction proposed for the British (b) design so that the hazard does not "Unified Code of Practice" related to ab- cause any local failure. normal loading conditions, origin and nature (c) allow the local failure to take place, of progressive collapse and tie-forces. but design the structure against progressive collapse. 135. Starr, C. Social Benefit Versus Technological Risk of internal explosions is covered and a Risk, What Is Our Society Willing to Pay for statistical method for evaluating the risk is Safety? Science, Washington. D.C., Vol. 165, presented. September 1969, pp. 1232-1238.

131. Ronan Point, Engineering News-Record, October An approach is offered for establishing a 30, 1969. p. 74. quantitative measure of benefit relative to cost for an important element in our spectrum of The article summarizes the Ronan Point social values—specifically, for accidental collapse and the conclusions of a special in- deaths arising from technological develop- vestigating board. It points out that thus far, ments in public use. The analysis is based on however, more than a year after the collapse, two assumptions. The first is that historical there is more discussion than action. national accident records are adequate for re- vealing consistent patterns of fatalities in the 132. Rozvany, G. I. N.. and Woods. J. F.. Sudden second assump- Collapse of Unbonded Underprestressed Struc- public use of technology. The is that such historically revealed social tures, Journal of the American Concrete In- tion preferences and costs are sufficiently endur- stitute. Proceedings, Vol. 69, No. 2. February ing to permit their use for predictive purposes. 1969, pp. 129-135. In the absence of economic or sociological Expenditures and theory demonstrate that theory, this empirical approach provides some unbonded prestressed slabs and rectangular insights into accepted social values relative beams having a smaller average prestress than to personal risk. the modulus of rupture become flexually un- stable at the cracking load. 136. Strengthening System-Built Blocks of Flats, Concrete, London, Vol. 3, No. 4, April 1969, 133. Saillard, Y., Le Comportement De L'Immeuble pp. 119-120. De Ronan Point En Comparaison Des Princi- Description of the work required to ples De Base Des Recommandations Inter- strengthen 29 blocks in inner London is given. nationales 'Structures En Panneaux' du Co- This action was undertaken after the Ronan mite Europeen du Beton (Behavior of the Point disaster and compHes with method B Ronan Point Building Compared to the Basic of the Institution of Structural Engineer's Principles of the International Recommenda- Notes for Guidance which was prepared to tion "Panel Structures" of the Comite du insure the flats can withstand a recommended Beton), Annales de I'lnstitut Technique du static pressure of 2.5 psi. The strengthening, Batiment et des Travaux Publics. No. 263, which was carried on from inside the build- November 1969, pp. 1804-1806. ing, involved the bolting of steel angles to Traces the development of the CEB recom- the precast concrete units of certain junctions,

19 thereby increasing the strength of the wall-to- 141. Systems Buildings, Engineering News-Record, floor joints. This work will provide a tensile Special Report, New York, Reprint from Oc- resistance at each floor level, in both direc- tober 30, 1969. tions, of more than 1,500 lb/ft. A history of systems buildings is presented together with a discussion of current trends in 137. Stretch, K. L., Explosions in Domestic Struc- U.S. construction. The efforts of European tures; Part Two: The Relationship Between Governments to increase building construc- Containment Characteristics and Gaseous Re- tion are evaluated and several systems de- actions, The Structural Engineer, London, Vol. scribed. 47, No. 10, October 1969, pp. 408-411. 142. The Technical Advisory Panel on Explosion Re- Explosions caused by vapor phase reactions search, England, 1969. between common inflammable solvents or sources of energy and air and the influence of Four major aims to follow in research on particular features of domestic buildings are explosion hazards in buildings are identified. examined. The inherent features of estab- The first should be a survey to determine the lished structural systems which have obscured incidence and nature of gas explosions as the necessity for special precautions in some well as their cause and effect, to determine the novel systems are discussed, as well as factors degree and nature of the risk. The second, to such as adequate venting, that should be in- determine whether the risk of explosion can be cluded in any satisfactory design code. Sim- reduced by providing ventilation methods to plified forms of the pressure waves are de- disperse dangerous vapors taking account of scribed and the impact on structures of tradi- their practicability and relation to heating tional brick design, of framed buildings and cost. The third, to determine whether the of concrete panel construction are analyzed. pressures created by unavoidable explosions can be eliminated or controlled by venting. 138. Structural Safety and Progressive Collapse. Con- Finally, the last project should be the study crete, London, Vol. 3, No. 2, February 1969, of the effects of the pressures from explo- pp. 47-48. sions on structures of various kinds to establish provisions that may be required in struc- Outlines developments in the British Insti- tures to resist pressures that cannot be tution of Structural Engineers and Comite avoided. Europeen du Beton following the Ronan Point inquiry panel report. It cites the basic docu- 143. Tests on Large Panel Construction, Bison Bulle- ments and designs principles endorsed by both tin No. 7, Concrete Limited, 399 Strand, groups to limit susceptibility to progressive London, W. C. 2., England, 1969. collapse of large panel structures. Tests were conducted on all aspects of the 139. The Structures of Large Panel Buildings, Cal- construction of the Bison Wall frame system culation and Design. Project of Polish Stand- in relation to the new criteria demanded by ards PN-68/B-032531, Warsaw, 1969. the Ministry of Housing Circular 62/68 (see

80) . In the tests, the behavior of walls and floors, the joints them were The subject of the standard is the structural and between design and detailing of large panel buildings. checked under an assumed force being equiva- The principles presented deal with residen- lent to a standard static pressure of 5 psi Further tests carried out tial houses, hotels, schools, hospitals, etc., of (720 Ib/ft^). were heights not exceeding 16 stories with load on floors to determine their resistance to bearing walls made of normal and lightweight debris-loading in the event of a partial col- aggregate concrete. lapse of the building.

144. Wiggins, H., Effects of Sonic Boom, J. H. 140. Structures to Resist the Effects of Accidental J. Wiggins Company, California, 1969. Explosions, US Department of the Army, the Navv, and the Air Force, TM 5-1300 NAV- Theoretical and experimental aspects of the FAC P-397, AFM 88-22 technical manuals, sonic boom are discussed along with measured respectively, Washington, D.C., June 1969. behavior of structural elements subjected to sonic boom. Claims for sonic boom damages The design of protective construction to are discussed from the standpoint of inspec- limit the effects of an accidental explosion is tion procedures and litigation experience. described. Among the items covered include

the basis for design, effects of explosions, and 145. Wilson, C, Gabrielsen, B., Edmunds, J., and construction details. Analysis and design for Bechtel, S., Loading and Structural Response both ductile and brittle mode response are of Wall Panels URS Research Company, Tech- discussed. nical Report, California, November 1969.

20 The progress on a long-range program to 148. Allgood, J. R., and Swihart, G. R., Design of investigate the loading, structural response, Flexural Members for Static and Blast Load- and debris characteristics of wall panels is ing, Monograph No. 5, American Concrete presented. The objective of the study, which Institute/ Iowa State University, Detroit, 1970. combines both analytical and experimental The fundamentals of blast dynamics are work, is the development of improved pre- reviewed, design criteria are established, and diction methods of the mechanics of struc- methods for the selection of reinforced con- tural failure and fragmentation. During this reporting period which extends from Decem- crete beams and slabs to resist static or blast loads are presented. A number of illustrative ber 1968 to August 1969, the major effort examples are given. References are made to has been devoted to an analytical program experiments that verify the fundamental con- which has included wall panel failure predic- cepts and to sources which present more de- tions to aid in the design of the experimental tailed discussion of specifics. test program; wall panel failure theory; development of statistical failure theory for 149. Apartment Building Collapses Despite Shoring, brick structures; and preliminary considera- Engineering News-Record, June 25, 1970, p. tion of preloaded wall panels. Effort was also 13. devoted to an experimental program which included loading tests, brick wall panel tests, A seven-year-old, 15-story reinforced con- concrete wall panel tests, interior sheetrock crete apartment building in Buenos Aires wall panel tests, a static test program, and a totally collapsed killing at least 15 persons small number of tests to investigate the effect and injuring several others. The article ex- of air blast on civil defense shelter ventilating plains the condition of the building at the equipment. time of collapse. Severe cracking had been noted in a number of columns and the structure had been shored. 1970 150. The Behavior of Structures When They Resist 146. Accident Analysis, Nuclear Safety. Vol. 11, Explosions, Editorial Comment. Concrete, No. 4, July-August 1970, pp. 298-308. London, Vol. 4, No. 3, March 1970, p. 87.

Nuclear plant safety is discussed with re- The editorial points out very little was un- spect to tornado threats. Several aspects of dertaken in the two years after the Ronan tornados are covered, such as probability and Point collapse to determine true dynamic be- design of vital structures. The most important havior and resistance of structures to gas ex- aspects covered are the tornado wind forces plosions and calls attention to limited test pro- and pressures and the possibility of tornado grams which indicate dynamic response to generated missiles which can produce a threat pressure pulses far exceed static analysis and to the stability of buildings. response.

151. Britain Tightens Building Standards. Moves to 147. Alexander, S. J., and Hambly, E. C, The Design Stem "Progressive Collapse," Engineering of Structures to Withstand Gaseous Explo- News-Record, April 16, 1970, p. 12. sions, (Part 1 and Part 2), Concrete. London, Vol. 4, No. 2, February 1970, 62-65. and pp. The article discusses the administrative Vol. 4, No. 3, March 107-116. 1970, pp. regulations issued in 1968 by the British government which have now been made by Par- A method is developed for the design of liament. The provisions are written especially structures to withstand the dynamic loading to prevent progressive collapse, like the struc- from gaseous explosions similar to that which tural failure at Ronan Point. Adoption of the caused the collapse at Ronan Point. The law's high-rise standards brought mixed reac- loading pressure pulse is described qualita- tion within the industry and these views are tively because a precise description cannot be presented. given because of the absence of relevant research data. The response of a structure to 152. Building Explodes as Gas Leak is Sought. Engi- such dynamic loads is discussed and a method neering News-Record, February 5, 1970. p. of design presented, with examples for floor 25. slabs and load bearing walls. It is shown that relatively small amounts of reinforcement pro- A gas line explosion leveled a two-story vide a substantial resistance to explosions. brick building in downtown Houma. La., on Proposals are given for the research that must January 24, killing three persons and dam- be carried out to determine the design pres- aging several other structures. The blast oc- sure pulse and to check the validity of the curred as a utility crew and firemen attempted assumptions made. to reach a reported leak.

21 153. The Building (Fifth Amendment) Regulations These recommendations are the result of 1970 Notes for Discussion (RP/68/04), The combining the CEB Recommendations for an Institution of Structural Engineers, London, International Code of Practice for Reinforced England, June 1970. Concrete (first edition 1964) and the draft FIP-CEB Recommendations for the Design The Institution has provided these notes as and Construction of Prestressed Concrete an interpretation of the sections of the Fifth Structures (edition issued in June 1966). Amendment. The notes are intended as a These earlier texts have been completely re- guide for engineers. vised in the light of the development of knowledge of the subjects. The basic feature 154. Building Regulations and Public Health and of these new 1970 Recommendations is that Safety, Editorial Comment, Concrete, Lon- they cover the whole field of joint concrete don, Vol. 4, No. 5, May 1970, p. 165. and steel action, from reinforced to prestressed concrete, both with regards to design Editorial traces the development of the con- and construction. Similarly, structural light- cept of "progressive collapse" and the design weight concretes have been considered along philosophies to limit failures to local col- with normal aggregate concretes. lapse. It criticizes the Ministry of Housing for issuance of "panic document 62/ 68" and 159. Creasy, L. R., Department of Civil Engineering the "unjustified 5 psi" criteria. Technical Instruction Serial 54, Department of the Environment, London, August 1970. 155. Canadian Structural Design Manual 1970, (NCR No. 11530), Supplement No. 4 to the Na- The technical instruction gives design pro- tional Building Code of Canada, National cedures and guidance on the interpretation of Research Council of Canada, Ottawa, 1970. the Fifth Amendment to the Building Regula- tions to improve building structures resistance This is an introduction to the Canadian to the onset of progressive collapse should Code of Practice provision requiring pro- damage occur locally. gressive collapse to be considered (see 177). 160. Creasy, L. R.. Interpreting the Fifth Amendment 156. Collapse Blamed on Gas Blast, Engineering to the Building Regulations, Concrete, Lon- News-Record, March 19, 1970, p. 3. don, Vol. 4, No. 6, June 1970, pp. 216-218.

The collapse of a block-long four-story, re- Because of the uncertainty of the term inforced concrete building in Godthaab, structural collapse and the doubt concerning Greenland, last week has been tentatively the distribution and magnitude of stress under blamed on an explosion in a gas line that such conditions, engineers and local authori- runs the length of the building in the base- ties have been interpreting the Fifth Amend- ment. Nine persons died in the collapse, which ment in a variety of ways. Mr. L. R. Creasy, dislodged central heat and gas main serving Chief Engineer to the U. K. Ministry of the six-building complex. Public Building and Works, discusses his interpretation of the document speaking only 157. Collapse of 10 Floor Sections Kills Two Work- as a structural engineer. A typical cast-in- ers, Engineering News-Record, March 5, 1970, place concrete building of framed construc- p. 15. tion was chosen as an illustrative example. Removal of various structural elements such Sections of 10 floors of a 20-story apart- as, slabs, columns, and beams, was then dis- ment building under construction in Pitts- cussed, and the strength which the remaining burgh collapsed killing two men. Apparently, members had to develop to prevent excessive an overload of masonry block on the con- structural damage was analyzed (see 163). crete plank floor of the 19th floor caused the

failure. The weight of the falling block and 161. Custard, G. H., Donahue, J. D., and Thayer, planking then sheared off 8X20 ft sections of J. R., Evaluation of Explosive Storage Safety nine floors of the building, finally dumping Criteria, Falcon Research and Development an estimated 40 tons of debris onto the 10th Company, Denver, Colorado, May 1970. floor. Relationships have been developed to help 158. Comite Europeen du Beton-Federation Inter- in the understanding of the risks which are nationale De La Precontrainte (International implied in the established explosive quantity- Recommendations for the Design and Con- distance criteria. These relationships provide struction of Concrete Structures. Principles a basis for estimating the potential damage to j and Recommendations), June 1970, FIP structures exposed in a blast field which is Sixth Congress, Prague, Cement and Concrete sufficient to cause incipient structural failure. Association, London SWI, 1970. The study was implemented through the defini-

22 .

tion of ten specific structures which have been A series of notes discussing individual sec- "exposed" to the blast forces from five charge tions of the English Building (Fifth Amend- sizes through analytical modeling techniques. ment) Regulations 1970 prepared by a work- Investigation was limited to target response to ing party of the Institution of Structural Engi- air blast forces with no consideration to neers to serve as a basis for a public discus- ground shock, fragmentation hazards (ex- sion of these regulations proposed to safeguard cept glass), fire hazards or other potential against progressive collapse. Contains de- threats. tailed, section-by-section comments on the proposed amendments. 162. Discussion on Explosions in Domestic Struc-

tures, The Structural Engineer, London, Vol. 167. Flak. H.. Hellers, B. G.. Holmgren. J., and Hog-

48, No. 8, August 1970 pp. 319-329. lund, T., Stormskador i Stockholmsomradet (Storm Damage in the Area of Stockholm), A series of discussions are presented which Statens Rad for Byggnadsforsking, R 44: deal with the papers The Relief of Gas and Stockhohn, 1970. Vapour Explosions in Domestic Structures, by D. J. Rasbash (see 127) and The Rela- This series of three reports deal with the tionship between Containment Characteristics frequency, nature and extent of damage oc- and Gaseous Reactions, by K. L. Stretch (see curring in various parts of Sweden during the 137). severe storms in the autumn of 1969. Most of the damage was done to roofs of structures but 163. Discussions to Interpreting the Fifth Amend- some buildings suffered wall damage due to ment to the Building Regulations. Concrete, progressive failure once the wall initially London, Vol. 4, No. July 1970, 275- 7, pp. ruptured. 276. 168. Full-Scale Strpnsrth Tests on Large Panel Con- Discussion on Mr. Creasy's interpretation struction, Precast Concrete, London, October of the Fifth Amendment with respect to the 1970, 283-290. example presented in his article Interpreting pp. the Fifth Amendment to the Building Regula- This article summarizes results of 137 static tions (see 160) tests of individual wall, roof, floor and joint specimens of the Bison Wall Frame System 164. Dobbs, N., and Cohen. E.. Model Techniques undertaken to demonstrate that the system and Response Tests of Reinforced Concrete met the requirements of the Fifth Amendment Structures Subjected to Blast Loads, Models to the British Code of Practice (see 143). The for Concrete Structures, 1970, ACI Publica- article describes in narrative form the pur- tion SP-24, pp. 407-447. pose, general procedure and main results of Model testing of reinforced concrete pro- the tests performed and concludes that this tective structures subjected to blast loads in system meets the newly proposed element re- order to verify design and construction tech- sistance criteria of the Fifth Amendment. niques required for comparative scaling indicate that damage sustained by the model and 169. Gas Explosion Rips Subwav Construction Site, full scale structures is similar if each is tested Engineering News-Record, April 16, 1970, in a similar manner, thereby establishing that p. 11. model tests may be used to evaluate the struc- Gas leaking from a pipeline at a subway tural response of full-scale reinforced con- construction site in a heavily congested sec- crete structures to high explosive detonations. tion of Osaka, Japan exploded, killing at 165. Draft Recommendations for the Choice of De- least 76 persons, injuring 240 and setting sign Schemes, Soviet Economic Mutual Aid, off a series of fires that destroyed 30 build- Moscow, February 1970. ings. The blast blew off more than 700 slab sections, each 6^/2 ft long, 21/2 ft wide, 8 in Section 6, Design Requirements for Acci- thick and weighing 880 lb, that were covering dental Loads, gives recommendations to fol- the excavation. low when designing a multi-story large-panel building in which there exists the possibility 170. Gas Facts—A Statistical Record of the Gas of an accidental explosion. The regulations Utility Industry in 1970 Data. American Gas give suggestions to be considered in choosing Association, Washington, D.C.. 1970. structural solutions for the building to prevent Presents statistical data for 1970 and sum- progressive collapse from a local failure. maries for earlier years for gas utilit)' indus- 166. The Fifth Amendment. Notes for next weeks ISE try. Data include information on reserves, discussion. Building, June 26, 1970, pp. 101- production, utilization and transmission and 102. distribution systems.

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171. Granstrom, S., Explosionsverkan—Ett Exempel less than a single-story height. The recom- Pa Katastrofpaverkan (Explosion—An Ex- mendations apply particularly where floor and ample of Overstress), Nordisk Betonkongres, roof are of concrete panel construction, but Copenhagen, Denmark, 1970, pp. 159—169. the principles should be taken to apply where other types of floor and roof construction are Discusses dangers of explosions in build- used. Clause 902 relates to recommendations ings. Surveys various types of potential explo- for accommodating local or general effects sions and main characteristics of each type. arising from constructional defects such as Among types of explosions included are high misalignment and lack of plumb. Clause 903 explosives, natural gas, dust, electrical, and to 908 inclusively, deal with the connections various types of gases. The paper describes between units, the tying together of the struc- the main characteristics of the Ronan Point ture, and the plan form of the building, aimed explosion and subsequent Scandinavian regu- at enabling the structure to accommodate a lations for minimizing the chance of a similar limited amount of accidental loading which accident. may occur as a result of construction load- differential settlement of the supports, 172. Greenfield, F. C., Holtum, R. D., and Kalra, J. C, ings, Large-Panel Construction in a London Bor- thermal movements, explosions, and acci- ough, Concrete, London, Vol. 4, No. 12, De- dental impact. Clauses 909 to 916 also relate in all types of precast con- cember 1970, pp. U3-447. to connections crete structures where connections and criti- A discussion of the implications on indus- cal sections of panels close to joints must be trialized building systems employing large- designed to resist the worst combinations of panel precast concrete construction, on the re- shear, axial force and bending caused by ver- quirements to strengthen structures to resist tical and horizontal loads. damage from explosions produced following the Ronan Point collapse of a large apart- 176. Leggatt, A. J., Design for Accidental Damage, ment building in London. An open discussions meeting to be held Jan- uary 14, 1971, The Structural Engineer, Lon- 173. Hodgkinson, A., What the Post-Ronan Point don, Vol. 48, No. 12. December 1970, p. 466. Building Regs Mean, The Architects' Journal, Leggatt is presented London, February 25, 1970, p. 473. An introduction by Mr. along with his definition of "accidental" dam- A structural engineer outlines the important age as related to the structural engineer. De- provisions of the Fifth Amendment to the ployment of the various responsibilities in the English Building Regulations. This short ar- conception and design of structures to others, ticle contains several very good sketches of the instead of solely on the structural engineer is alternate design conditions assumed under the advocated. It is pointed out, although certain path criteria. The article is generally critical responsibilities may be neatly delegated to of the new requirements from practical appli- others, in practice the structural engineer cation and philosophical standpoints. often has to do it alone, especially when it comes to developing new materials or tech- 174. Joints for Precast Concrete Components, Sym- niques. It is further suggested that by com- posium at University College of Cardiff. De- piling a code for guiding the structural engi- cember 1970. Organized Jointly by Wales neer in the use of new materials and tech- Branches of the Concrete Society and Insti- niques, partial protection may be afforded tution of Structural Engineers. Concrete, between excessive caution on the one hand and London, Vol. 4, No. 3, March 1970. 105- pp. excessive boldness on the other. Several rules 106. for guidance are given for the structural A brief report on a two day symposium held engineer to follow when using new material in Wales to disseminate information on proper and techniques (for discussion see 214) design of joints between precast concrete 177. NationalBuildinsCodenf Canada, 1970. (NRCC elements. The report outlines the key factors 11246), Associate Committee on the Na- to be considered in joint design with empha- tional Building Code, National Research sis on meeting the new requirements imposed Council of Canada, Ottawa, 1970. after the Ronan Point collapse. Section 4.1.1.7 covers the subject of pro- 175. Large-Panel Structures and Structural Connec- gressive collapse (for supplement see 155). tions in Precast Concrete, Addendum No. 1 (1970) to British Standard Code of Practice 178. Notes for Guidance. London Building (Con- CP 116:1965 and CP:Part 2: 1969, British structional) Amendina; Bv-Laws 1970, Greater Standards Institution. London, England 1970. London Council, London England.

The addendum relates to structures which These notes have been prepared in consulta- utilize precast load-bearing wall panels of not tion with the District Surveyor's Association

24 (London) for the guidance of those responsi- empty roof-top swimming pool 65 ft long by ble for the design and construction of build- 20 ft wide contributed to the collapse. ings in the Inner London area with a view 182. Rasbash, D. Palmer, K. N., Rogowski, Z. W., to explaining the application of the Amending J., and Ames, S., Gas Explosions in Multiple By-Laws 2.06 (1) to (9), Vehicular Impact, Compartments, Fire Research Station, Fire and Amending By-Law 3. "This explanatory Research Note No. England, November document in many ways reflects the thinking 847, 1970. of the CP. 116 Addendum with regard to peripheral and internal tie forces, their de- Experimental tests were conducted to define velopment, relation to story height, and gen- the data needed in the mathematical modeling eral details: It confirms the views of the of gas explosions in buildings. The explosions Structural Document that most fully framed took place in a strong chamber with partitions structures wiU meet the requirements." simulating the division of a building into rooms. Explosive mixtures of air and manu- 179. Otway, H. J., Battat, M. E., Lohrding, R. K., factured gas or air and natural gas were used. Turner, R. D., and Cubitt, R. L., A Risk Pressures substantially larger were obtained Analysis of the Omega West Reactor, Uni- than those which might be expected if no par- versity of California, Los Alamos Scientific titions were present. Laboratory, Los Alamos, New Mexico, July 1970, pp. 4r-5. 183. Second Annual Report of the Secretary of Trans- portation on the Administration of the Nat- A method for estimating the risk from ural Gas PipeHne Safety Act of 1968, Depart- reactor installations is presented. The method, ment of Transportation, Washington, D.C., which considers both accident probabilities, April 1970. estimates individual risk as a function of direction and distance from the reactor. Com- The report is a compilation for the calendar parison of reactor risk is then compared with year 1969 of gas pipeline accidents and cas- the numerical values of risk that are com- ualties based upon failure reports received monly accepted such as. motor vehicles, fires, by the Office of Pipeline Safety. Classification lightning, etc. of incidents are in terms of date, state, city, number of injuries, number of fatalities, 180. Pipeline Accident Report. Low-Pressure Natural property damage, and cause. The report lists Gas Distribution System, Burlington, Iowa, the Federal Gas Pipeline Standards presently National Transportation Safety Board, Report in effect, evaluation of the degree of observ- No. NTSB-PAR-70-1, Washington, D.C., ance of applicable safety standards, analysis October 1970. of research activities as a result of Federal Government and private sponsorship, pend- During a highway construction project in ing or completed judicial actions, dissemina- Burlington, Iowa, a bulldozer drove over and tion of technical and consumer-oriented in- partially collapsed the steel covers of a gas formation, and recommendations for addi- regulator pit, damaging the regulator. The tional legislation. regulator served to reduce high-pressure gas to low pressure for distribution of the Iowa 184. Soviet Ekon. Wsaimooomoshtshi : Rekomenda-

Utilities . Southern Company (ISU) While cii Po Vvboru Rastshotnych Schiem-Ra- the pressure was partially controlled by a botsnyi Material, Moscow, February 1970. monitoring or safety regulator, gas, report- edly at four to five times the normal operating Design Code for Socialistic Countries. pressure, entered the distribution system. Gas customers in the affected area reported high 185. Special Studv of Effects of Delay in Shutting gas pilots and fires to ISU and the fire de- Down Failed Pipeline Systems and Methods partment which caused major damage to the of Providing Rapid Shutdown, National Trans- interiors of 10 houses and minor damage to portation Safetv Board, Report No. MTSB— kitchens and appliances in 42 others. Prop- PSS-71-1, Washington, D.C., December erty damage was estimated at $80,000. 1970.

181. Poor Materials, Roof-Top Pool Blamed for Col- In recent pipeline accidents, a delay in lapse, Engineering News-Record, February 26, promptly shutting down the failed pipeline systems has magnified the effects of the ac- 1970, p. 13. cident. The study points out that by reducing A 15-story reinforced concrete apartment the time between failure and shutdown, the building scheduled for occupancy in 5 months accident effects can be minimized or elim- totally collapsed in Buenos Aires. Initial find- inated. Some of the methods and tvpes of ings suggest that inferior materials and ex- equipment that are presently available for cessive roof weight caused the collapse. An use in a rapid shutdown are discussed. The

25 need for Federal regulations and guidelines tecture and Civic Design, Structural Engi- in this area is pointed out by the fact that neering Division, January 6, 1970. the current regulations would not have prevented any of the accidents referred to in the Contains design and detailing procedures study. The study also discusses the degree of for carrying out the intent of amendments security to be provided for the public with to the Building Regulations design to mini- respect to, the relative hazard of the commod- mize risk of progressive collapse. Prepared ity, the size of the population-at-risk at points for engineers designing high-rise buildings along the pipeline, and the potentially dam- to be built in the London district. Considers aging effects on property and the environ- many types of buildings and suggests where ment. checks should be made in each.

186. Stability of Buildings and Their Design for Pre- 190. Supplement, London Building (Constructional) vention of Progressive Collapse Due to Local Amending By-Laws, 1970, Greater London Damage. Report of Nordic Sub-Committee on Council, London, England. Large Concrete Panels, Nordic Concrete As- The document shall be substituted for by- sociation Committee on Regulations, Sweden, law 2.06 of Part II (General) of the London January 29, 1970. Building (Constructional) Amending By-Laws Guidelines are presented for recommenda- (no. 1) 1964. It has the same intent as the tions on design of all buildings to prevent the Building (Fifth Amendment) Regulations but possibility of progressive collapse. This re- with a number of modifications. port formed a basis for work on a supplement 191. Tenement Hit by Car Collapses, Washington to Swedish Building Norm (SBN) taking Post, Washington, D.C., August 2, 1970. into account the risk of accidental damage. A car crashed into a five story tenement 187. Statutory Instrument 1970 No. 109. The Build- building in New York knocking out a building (Fifth Amendment) Regulations, Her ing support and sent tenents and parts of Majesty's Stationerv Office, London, England, apartments crashing into the street. The car 1970. crossed the sidewalk, knocked over a fire These regulations amend the Building Reg- hvdrant, side-swiped a wall and crashed into ulations 1965 by imposing additional require- the ground floor section of the building. The ments as to the structural stability of build- removal of the building support caused the ings of five or more stories (including any second floor to collapse and then the third, basement). Buildings must be constructed so fourth and fifth in a chain reaction. that if any portion of any one essential structural member (other than a portion which 192. Twin Gym Collapse Is Double Trouble, Engi- 40. satisfies certain specific conditions as to load) neering News-Record, January 8, 1970, p. were to be removed, the consequent structural Two identical, steel-framed hexagonal failure would be limited as specified in the school gymnasiums in Tennessee collapsed Regulations. The Regulations also add to within 12 h and 12 miles of each other. Both deemed-to-satisfy provision in relation to the gyms failed at precisely the same points where same matters. The regulations apply to all trusses joined a tension ring but whether or forms of construction, cast-in-place and pre- not the failures were caused by material, de- cast concrete, structural steel, large panel, sign or other defects has not been determined. masonry, etc. Explosion 188. Strengthening Tower Blocks of Large-Panel 193. Ventilation in Dwellings to Reduce the Institution of Heating Construction, Concrete, London, Vol. 4, No. Risk, Journal of and Ventilating Engineers, London, Vol. 38, 4, April 1970, pp. 142-143. July 1970, pp. 92-94. A new device is described for strengthening held at multistory structures built from large panels This is a report on a colloquium Ventilating so that they will comply with the new British the Institution of Heating and prompted by regulations, introduced since the collapse at Engineers. The meeting was the ex- Ronan Point. Steel angles are positioned along Reconunendation 21 of the report on should the internal joints of the structure and bolted plosion at Ronan Point, "Consideration ventilation to the fall and floor slabs against which they be given to means of improving abut. in flats and high blocks," and paragraph 172 of the report which remarked that the tend- 189. Structural Design Requirements for Council ency of escaping gas to accumulate in the Buildings, Divisional Instruction No. 5, upper parts of rooms could be greatly re- Greater London Council, Department of Archi- duced by ventilation.

26 . — .

1971 197. Astbury, N. F., West, H. W. H., Hodgkinson, H. R., Cubbage, P. A., and Clare, R., Experi- 194. Adams, H. C, The Design of Brickwork Against ments to Determine the Resistance of Brick Gas Explosions, British Cercimic Research As- Buildings to Gas Explosion, British Ceramic sociation, Proceedings, Second International Research Association, Proceedings Second In- Brick Masonry Conference, Stoke-on-Trent, ternational Brick Masonry Conference, Stoke- 1971. on Trent, 1971.

The paper discusses the accidental damage A programme of experimentation has been concept and possible causes of abnormal load- undertaken to determine the nature and ex- ing, and describes the nature of explosion tent of the forces generated by normal domes- damage to brickwork. Design requirements tic gas explosions, and to determine the ef- are considered in relation to the Building fect of such forces on brickwork panels and (Fifth Amendment) Regulations and to the on conventional loadbearing brickwork struc- possibility of providing venting relief. The tures. The effectiveness of venting has been "alternative path" bridging solution is the established and the pressures at which this preferred design method at present. occurs measured. The pressure necessary to damage a 4% in brick wall, an 11 in cavity 195. AUen, D. E.. Schriever, W. R., and Plewes, W. wall and a 9 in wall have been measured. G., Structural Integrity. Commentary No. 7, Pressure profiles have been established for Supplement No. 4 to NBC 1970, Canadian balloon and layered explosions and for natural Structural Design Manual (NRCC 11530), and town gas. It has been shown that the ac- National Research Council of Canada. Ottawa, tual pressure developed is in good agreement 1971. with that estimated from the heat content of the gases. The effect of cascade explosions This commentary gives guidance to the de- proceeding from one room to another has signer by defining the term structural integ- also been examined. rity, outlining the abnormal loads to be considered, and indicating the general design 198. Blast Leaves 620 ft British Tower Intact, Engi- approach to be utilized to avoid progressive neering News-Record, November 11, 1971, collapse (see 177) p. 15.

196. Astbury. N. F., West, H. W. H.. and Hodgkin- A bomb blast in London's 36-story British son, H. R., Experimental Gas Explosions General Post Office Tower blew out about Report of Further Tests at Potters Marston, one-third of one upper floor's window wall, Fourth Symposium on Load-Bearing Brick- but did not cause any structural damage. work at the Mount Royal Hotel, British Cer- About 10 lb of dynamite was responsible for amic Society, London, England, 1971. the blast.

Experiments involving gas explosions were 199. BoTTib Data Report. California Department of carried out to investigate the effect of differ- Justice Criminal Intelligence Branch, Califor- ent layering conditions in a pair of rooms. nia, 1971. During the tests, different layers of both gas and a gas/ air mixture were used. In two of Statistical data on property damage, prop- these experiments, the most explosive (stoichi- erty loss, deaths and injuries, cities and tar- ometric) mixtures of manufactured gas and gets most consistently hit, and monthly air were obtained and the resulting explo- threats are analyzed for 1084 California sion caused, in one case, minor, and in the bombing incidents reported during 1971. other case, major damage to the S^^-story building which was of load-bearing brick. These experiments were a repeat of earlier 200. Boston Collapse Comments, Reader Comment, tests in which an attempt was made to dem- Engineering News-Record, August 19, 1971, onstrate the effects of turbulence. Turbulence p. 7. has the effect of increasing the pressures developed when an explosion proceeds from one This letter explains some of the findings of room to another filled with gas, namely, the the investigating commission and its con- "cascade" effect. The test demonstrated the sultants with respect to the 16-story apart- effectiveness of venting in limiting the maxi- ment building collapse in Boston. The in- mum pressure developed in an explosion. De- vestigators found the construction did not spite suffering extensive damage, the brick conform to the design documents and the building could be safely propped and no pro- concrete strength in the roof slab was sub- gressive collapse occurred. stantially below specified strength (see 204)

27 201. Bradshaw, R. E., and Foster, D., Two Load- occurred when the roof slab failed in shear Bearing Brickwork Buildings in Northern around a column. The report noted errors in England, British Ceramic Research Asso- the detailing of the structural plans and prob- ciation, Proceedings Second International ers found that rebars were missing in col- Brick Masonry Conference, Stoke-on-Trent, umns. The roof slab was subjected to a tem- 1971. porary construction overload by the weight of the freshly placed mechanical floor slab. The paper describes two calculated brick- The concrete strength on the roof was less work buildings; one a completed fourteen- than specific-substantially below 3,000 psi story block of flats at Oldham, and the other (see 229). a four/five-story slender cross-wall hostel at York. Foundations, wind loading and pro- 205. Building Collapse Brings Indictments, Engi- gressive collapse are discussed in relation to neering News-Record, December 23, 1971, p. the design of both blocks. Comments on the 3. construction of the completed block are in- Four persons are each charged with four cluded and details of costs of structural work counts of manslaughter, and six persons and for both blocks are given. one corporation are charged with conspiracy violate the Boston Building Code in con- 202. Brondum-Nielsen, T., Prevention of Structural to with the January 1971 apartment Collapse (3.1). Build International, London, nection building collapse (see 206). Vol. 4, No. 5, September/October 1971.

Fatal Collapse Unknown, Engineering Author maintains that the use of large con- 206. Cause of 13. crete panel systems for multi-story buildings News-Record, February 4, 1971, p. involves a risk of progressive collapse, which The cause of the progressive collapse from a requires new design philosophy. Local col- the 16th story through the first floor of the lapse is caused by abnormal situations and reinforced concrete apartment building in the risk of such situations may be reduced Boston is still unknown (see 229) . The build- but is cannot be eliminated. Thus, there a ing is of flat plate design and three possible need to design the structure not to resist local causes for the collapse are discussed. collapse, but to resist a progressive collapse. The best way to prevent progressive collapse 207. Collapse Blamed on Deficiencies in Design, Engi- is to supply alternative paths for the transfer neering News-Record, New York, March 11, of loads in the event of the loss of a critical 1971, p. 15. member. The collapse in Brazil of a reinforced con- 203. The Building Collaose at 2000 Commonwealth crete exhibition hall under construction that Avenue, Boston Massachusetts, Report of the killed 65 workers was blamed on insufficient Mayor's Investigation Commission, City of reinforcing steel and insufficient allowance Boston, Boston Public Library, Boston, Mass- for settlement of the building's foundation. A achusetts, June 1971. 278X98 ft section of roof fell after removal of the last of the shoring that supported the An extremely detailed report of the Investi- slab cast three months earlier. Before the col- gating Commission appointed by the Mayor of lapse, one of the supporting columns report- the City of Boston after collapse during con- edly sank, leaving a depression around its struction of a 16-story reinforced concrete base (see 208). flat plate apartment building. The Commis- sion concluded that a shear failure around 208. Collapse of Reinforced Concrete Roof Kills one column propagated laterally to include 30, Engineering News-Record, February 18, an entire half of the structure at both the 1971, p. 12. roof and later at the 16th floor. The structure government then collapsed progressively vertically to the The article reports that a Brazil is investigating the recent ground. Principal causes of failure were at- agency in of reinforced tributed to inadequate shoring and low con- collapse of the newly cast roof a slab, crete strength as well as numerous construc- concrete building. The concrete roof the tion and inspection irregularities. 279X148 ft in plan crashed 41 ft to ground almost immediately after a worker 204. Building Collapse Blamed on Desisn, Construc- knocked out the last section of shoring sup- tion. Engineering News-Record, July 15, porting the completed roof. It is believed of the roof slab on its columns 1971, p. 19. that the weight must have caused the ground to settle. The crucial failure in Boston which started the progressive collapse of two thirds of the 209. Correction. Reader Comment. Engineering News- building from the 16th through the first floor. Record, February 11, 1971, p. 7.

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The January 28, 1971 report of the Boston Excerpts from the ref>ort of the Blue Rib- apartment building collapse erroneously de- bon Commission, set up by the City of Bos- scribed the building as having a steel frame. ton for the purpose of enquiring into the The building's frame was reinforced concrete cause of the 16-story apartment building col- (see 229). lapse, are given to correct errors and omis- sions made by ENR which may have raised 210. Creasy, L. R., Partial Stability, Design Circular, the erroneous inference that the collapse was Directorate of Civil Engineering Development, caused by design faults (see 200 and 204). Department of the Environment, London, England, August 1971. 214. Discussion. The Economic and Social Factors of Design for Accidental Damage, The Struc- Design procedures are described to insure tural Engineer, London, Vol. 49, No. 7, July "partial stability" of a structure for the pre- 1971, pp. 299-305. vention of complete disaster following the onset of a local mishap. This "stability" is A series of discussions are presented which based on the "catenary" and "membrane" deal with economic and social aspects of de- chara(cteristics of the components of the sign for accidental damage including relative framework where adjacent components to risk of severe damage to high rise buildings the damaged ones must be capable of "bridg- as compared to both low and medium rise ing" or "stringing" over the area of local as well as transportation accident risks (see damage. Tests were made at Imperial College, 174). London on beam and slab specimen to confirm the possibility of the suggested design pro- 215. Dowding, C. H., Response of Buildings to cedures. Ground Vibrations Resulting from Con- struction Blasting, Doctoral Dissertation, 211. Cutler. J. F., Plewes. W. G., and Mikluchin, P. University of Illinois at Urbana, Champaign, T., The Development of the Canadian Build- 1971, 219 pp.. Dissertation Abstracts, Vol. ing Code for Masonry, British Ceramic Re- 32: 10(B), University Microfilms Order No. search Association, Proceedings Second In- 72-12, 143. ternational Brick Masonry Conference, Stoke- on Trent, 1971. An assessment of the damage potential of blasting vibrations through the application of During the past decade a successful vigor- response-spectrum-analysis techniques is in- ous effort has been made in Canada towards cluded in the paper. the implementation of modern technical developments in the structural design of mas- 216. Draft British Unified Code for Structural Con- onry. These efforts resulted in the codification crete. Notes on Clauses for Preventing Pro- of theoretical and experimental results in gressive Collapse, CIB Commission W 23, the form of a modern Building Code. In Venice, October 1971. developing suitable code regulations, critical evaluation of structural research information Contents of the draft apply to all concrete reported by other countries has been taken structures. The extent of primary damage due into consideration. The paper explains how to unpredictable loads is not defined, in- research information has been put to use in stead it is stated that "there should be a Canada and underlines the Canadian approach reasonable probability that the structure will to several questions which may be considered not collapse catastrophically." A factor of in some way special to the overall develop- safety of 1.05 is required in designing ment of engineered load-bearing masonry. against the effects of excessive loads. Sta- Section 9 especially deals with design against bility requirements for all concrete structures progressive collapse. are in the form of force requirements. The principle involved in the draft is one of en- 212. Design To Avoid Progressive Collapse, Chapter suring that the structure is adequately tied 21 and Chapter 22 of Svensk Byggnorm 67 together in all directions. It is recognized (SBN). Statens Planverk, Draft August 1971. that the effects of excessive loads are impos- of the tie Svensk Byggnorm 67 consists partly of sible to quantify and the magnitude reasonable regulations which are compulsory both for forces have been chosen to eive a collapse, when the builders and the authorities, and partly probability against catastrophic of recommendations which are optional. The used with the design methods given in this loads. regulations shall, with certain exceptions, be Code dealing with normal applied from the 1st January, 1968. (English Ferahian, R. H., Design Against Progressive Translation of 345). 217. Collapse, Technical Paper 332 (NRCC 11769) 213. Design Was Not Cause of Collar)«e, Engineering Ottawa, National Research Council of Canada, News-Record, November 11, 1971, p. 16. Division of Building Research, July 1971.

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This paper presents background data and The state of interest and research into the recommendations needed to help chart fu- risk and danger of gas explosions in the ture action in formulating rules for codes of Netherlands is outlined. Tests were conducted practice and research in the field of large with natural gas explosions in dwelling rooms panel structures with particular emphasis on to determine pressures required for building all aspects of progressive collapse. All the design. The two rooms were connected and unusual and accidental loads that can cause various wall sizes were used with different progressive collapse are presented and their sizes of window openings and thicknesses of nature and damage potential discussed. Gas glass. It was concluded that the conversion of explosions as a cause of progressive collapse a dynamic explosion pressure on binding ele- are comprehensively treated in light of the ments into a static pressure for design de- British experience with the Ronan Point Dis- pends upon many parameters and should be aster and the subsequent legislation leading further investigated. It was further determined to the Fifth Amendment of the Building Regu- that window glass which is not too thick and lations 1970. British and European thinking windows which are large enough are an ad- and practice are compared. With this as back- vantage in keeping explosion pressures in ground, the current Canadian approach for dwelling down. the prevention of progressive collapse, as given in the National Building Code of 221. Gas Line Explosions Draw Attention to Inade- Enforcement, Engineering Canada, 1970, is appraised. quate Laws and News-Record, April 15, 1971, pp. 9-10.

218. Field Survey of the Damage Caused by Gaseous Contractors cause more than twice as many Explosions, Construction Industry Research gas line accidents as any other single source, and Information Association, London, Oc- according to the Department of Transporta- tober 1971. tion. During 11 months in 1970, the gas utility industry reported 1,019 leaks and 26 related The frequency and severity of gas explo- fatalities. Damage to distribution or low- sions was examined and the conclusion was pressure gas lines accounted for 676 of the reached that roughly one severe or very leaks, 462 of which were caused by outside severe explosion occurs every two weeks. forces. There was some evidence that the incidence Resistance of Buildings to of explosions is increasing. 222. Gifford. R. W., The Accidental Damage, Bison Limited, Notes of the paper presented to the Los Angeles Con- 219. Fry, F., J. Gas Explosions Attended by Fire vention of the PCI, London, England, 1971. Brigades in Dwellings, Journal of the Insti- tute of Fuel, England, August—September The accident at Ronan Point is briefly re- 1971. viewed and a discussion on its technical cause is presented. A historical summary of the United Kingdom fire incidents involving ex- various documents produced in the United plosions of manufactured gas in dwellings Kingdom following the incident is covered, during the 13 years, 1957 to 1969. were ex- giving a background to the thinking behind amined. The average annual incidence was the documents and a short commentary on shown to be approximately 90 but appeared to them. Finally, a discussion on current prac- be increasing as the consumption of gas in- tice and a look at possible future trends is creases. The average rate of incidents is about presented. 5.0 per 10® therms of gas sold. Approximately 223. Granstrom, S., Bygger Vi Korthus? Byggnads- 48 percent of the incidents cause some struc- industrin 19, Stockhohn, 1971, pp. 50-51. tural damage and in 40 percent of these it was considered "severe." From reports involving Outlines several examples of progressive manufactured gas and natural gas in 1969, it collapse which have occurred including Ro- appeared that natural gas was more likely to nan Point, Godthaab New York, Auch and a cause explosions, but that the explosions gas explosion in Gubbin2;er. Describes model were of similar violence for the two types tests used to study progressive collapse in of gas. building structures and summarized current Scandinavian Building Regulations which at- 220. Gas Explosion in Wohnhochhausern (Gas Ex- tempt control of progressive collapse. plosions in Highrise Apartment Housing) Impressions from the conference entitled 224. Granstrom, S., Bvggnaders Stabilitet Efter Kat- Niederlandischen Betontag in Utrecht. Part astrofskador. Krafter i Elementfogar-Modell- Two, Die Bauwirtschaft Wiesbaden, Vol. 1—2, forsok (Stability of Buildings after Accidental January 1971, pp. 10-11. Damage. Forces in Element Joints-Model

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Tests), Statens Institute for Byggnadsfor- scheme at Portsdown, Hampshire are de- skning, Report R20:1971, Sweden Symposium scribed. The scheme includes fifteen, seven- at University College of Cardiff, December teen and nineteen-story tower blocks, of which 1970. Organized Jointly by the Concrete So- thirteen, fifteen and seventeen stories respec- ciety and Institution of Structural Engineers. tively are constructed in load-bearing brick- For summary of papers see Concrete, London, work. There is an associated low-rise develop- Vol. 4, No. 3, March 1971. ment of four, six, and eight-story load-bearing brick buildings. The engineering design of Model tests, to scale of 1 : 20, involving the nineteen-story block is described and the studies of joint forces and framework de- brickwork strengths are given, together with formations in buildings which have sustained an outline of the specification used. The early local damage are described. The tests relate construction difficulties and techniques are mainly to domestic and office buildings of indicated. Section 3.4 especially deals with precast concrete. The results show that pro- progressive collapse. The paper is illustrated viding joint connections, even of moderate with diagrams, plans and photographs of the strength, can reduce dramatically the proba- building. bility of collapse of buildings. 228. Haseltine. B. A., and Thomas, K., Load-Bearing 225. Granstrom, S. A., and Carlsson, M., Building Brickwork Design for the Fifth Amendment Design for the Avoidance of Progressive Col- (To the 1970 Building Regulations). Techni- lapse (Byggnaders ut Formning for Undvi- cal Note, Vol. 1, No. 3, Brick Development kande av Fortskridande Ras), Library Com- Association, England, July 1971. munication No. 1670, Statens Institut for Bvggforsknins; Projekt C653:2, Stockholm, This technical note summarizes the ap- July 1971. .proaches that designers may take to design and detail load-bearing brick structures to Over 20 various cases of building collapse safeguard against progressive collapse follow- are described in fairly great detail. Illustra- ing removal of one or more load-bearing walls tions and photographs of the collapsed build- in an accident such as a gas explosion. The ings are also included. A substantial biblio- note includes several detailed calculation ex- graphy is included. amples as well as a summary report of a test series assessing lateral load resistance of 226. Guidance on the Design of Domestic Accommo- axially loaded brick walls. dation in Load-Bearing Brickwork and Block- work to Avoid Progressive Collapse Follow- 229. High-Rise Fails During Construction, Engineer- ing an Internal Explosion Institution of Civil ing News-Record January 28, 1971, p. 3. Engineers, 4th Svmposium on Load-Bearing Brickwork. British Ceramic Society, London, Half of a 16-story luxury apartment build- 1971. ing under construction in Boston collapsed. The roof, which was being concreted, failed A committee convened by the Institution first, and a half hour later, an entire wing of considered the probable effects of an explo- the building collapsed (see 209) sion of the severity of that which occurred at Ronan Point in domestic accommodation con- 230. Highway Accident Report. No. NTSB-HAR-71- structed of load-bearing brickwork or block- 6. National Transportation Safety Board, work. They have considered the extent of the Washington, D.C., May 12, 1971. major structural damage which is likely to 30, 1970. a tank truck partially arise and have tried to provide guidelines on On May liquefied oxygen exploded, with- which the design of new construction should filled with after making a delivery at the be developed in order to avoid progressive out warning, Hospital in Brooklyn, New collapse occurring in these circumstances. Victory Memorial the explosion and ensuing They suggest solutions for strengthening York. The force of resulted in fatal injuries to the driver buildings at both ends of the sensitivity to fire injuries to 30 other progressive collapse spectrum. and a bystander, minor persons, and substantial property damages. contains the probable cause of the 227. Haseltine, B. A., and Au. Y. T.. Design and The report contributory hazards. Of par- Construction of a Nineteen-Story Load-Bear- accident and calculations of prob- ing Building, British Ceramic Research As- ticular interest are the present in the accident. sociation, Proceedings Second International able pressures Brick Masonry Conference. Stoke-on-Trent, Y., Yamanouchi, 0.. and Ota, Y., Rec- 1971. 231. Kanoh, ommendations on the Structural Design of 5 The circumstances leading up to the deci- Storied Apartment Houses in Precast Con- sion to use brickwork for a large housing crete Wall Systems; Seminar Under the

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Japan-US Cooperative Science Program, Con- 234. Ligtenberg, F. K., Structural Safety and Fire struction and Behavior of Precast Concrete (1.3), Build International, London, Vol. 4, Structures, Seattle, August 1971, pp. 211-222. No. 5, September /October 1971.

This report is a commentary of the pro- An analysis of damage caused to buildings posed recommendations on the structural shows that overloading and inferior materials design of the apartment houses in wall cause trouble, but more frequently damage is system construction, composed of the pre- caused by fire and collisions. The author con- cast concrete large panel units. The apart- cludes that fire is a loading case that must be ment houses designed to the recommenda- explicitly treated in structural calculations. tions are the most typical of the industrialized More data, especially on material properties housing in Japan. Background and the design under fire conditions, are needed. He states procedure of the recommendation are ex- that in Netherlands there are some 4,000,000 plained. Safety provisions are examined by buildings and that in 1967, 20 collapsed from to the full-size test results conducted by Build- local overload, 50 collapsed due material ing Research Institute. A part of the transla- defects or design error, around 100 were tions of the recommendations are shown as badly damaged in collisions, 200 were dam- an appendix. aged in explosions, and in 200 cases wind caused sizable damage. In contrast, 15,000 experimental fires with 1,500 having severe 232. Lewicki, B., Constructions Industrialisees en fire damage indicates that assuming a 100 Grands Elements Conception des Joints — year life, some 5 percent of all buildings will Prevention Coutre la Rupture de Proche en experience fire damage in their useful life Proche (Industrialized Construction with and must be considered in design. Large Panels—Design of Joints for Preven-

tion of Progressive Collapse) , Comite Euro- 235. Lugez, J., Influence Des Joints Horizontaux Sur pean du Beton, Bulletin D'Information No. Les Structures En Grands Panneaux (Influ- April 1971, 89. 77, p. ence of Horizontal Connections on Structures Made from Large Concrete Panels), Comite very informative summary of the de- A Europeen du Beton, Bulletin D'Information velopment of joint design in precast struc- No. 77, April 1971, p. 157. tures with emphasis on joints in large panel structures. Gives detailed suggestions for de- This report details the various require- sign of structural svstems to minimize danger ments of horizontal joints in panelized con- of progressive collapse (i.e., tension or sus- struction. It considers the role of the joint pended slab systems) and for practical tie in developing overall structural action, possi- beam and joint design. ble effects of joints on the vertical load capacity of the joints, and the role of the joints 233. Lewicki, B., Prevention of Progressive Collapse, in transferring lateral shear loadings. Design Beton-En Betonconstructies 1. De Ingenieur, formula and typical schematics of joint de- Netherlands, February 12, 1971, pp. 7-11. tails are given.

A general discussion of the work done by 236. Mainstone, R. J.. The Breakage of Glass Win- different agencies including the European dows by Gas Explosions, Current Paper 26/ Concrete Committee (CEB) on progressive 71, Building Research Station, England, Oc- collapse is outlined. Broad definitions, as tober 1971. given by the Scandinavian Draft Stability of Buildings and Their Design for Preven- Existing ejperimental data on the strength tion of Progressive Collapse due to Local of glass under loads of very short duration Damage, are listed for the unpredictable are reviewed. The basis for graphic presen- loads and effects which are not taken into tation of likely breaking pressures, under gas- account in the design of buildings. Several explosion loading, for particular sizes and codes or working documents are then dis- thicknesses of window panes is provided. An cussed with respect to the unpredictable mag- earlier review by Rasbash (see 127) of data nitude of local extreme loads and the extent to on the venting of gas explosions was then which local damage must be limited. Also dis- used as a basis for extending the graphic cussed in this paper are the Scandinavian presentation to cover also the possible rise in Draft, The British Addendum No. 1, The pressure after the glass is broken by explo- Italian Code of Practice, the Preliminary In- sion. The graphic presentations can be used dications for Design Recommendations for directly for estimating the pressure reached Large Panel Buildings of Socialist Countries, in actual explosions from observations on the and The CEB-Recommendations for Large- damage to glass windows. They may be used Panel Structures. in design of glazing as an explosion vent.

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237. Mattock, A. H. and Hawkins, N. M., Research The National Bomb Data Center has re- on Shear Transfer in Reinforced Concrete Re- ported a broad analysis of fire and explosive port SM 71-2, University of Washington, bombings in the US during the period July Department of Civil Engineeering, Seattle, 1970 through June 1971. Bombings are class- Washington, August 1971. ified according to state, region and population group. The report deals with property dam- Tests were conducted in a continuing in- age and the number of casualties. The fre- vestigation of the parameters affecting shear quency of incidents is analyzed in terms of transfer strength in reinforced concrete. Some target, motive and the type of explosive used. of the factors which have been studied are (1) the characteristics of the shear plane, 241. Multistory Framed Buildings, Circular No. (2) the characteristics of the reinforce- 11/71 Building Regulations 1965, Depart- ment, ment of the Environment, London, February, (3) the concrete strength, and 1971. (4) direct stresses acting parallel and transverse to the shear plane. The Circular states that in general, multi- Shear transfer in design from the ACT Build- story buildings having a fully framed struc- ing Code, ACI, 318—71, is reviewed. Con- ture in concrete or steel which comply with clusions based on the test results are included. RP/68/05 from the Institution of Structural Engineers will be appropriate for the applica- 238. Monthly Summary Reports, January through tion of a waiver from the special provisions December 1971, National Bomb Data Center, designed to guard against progressive collapse International Association of Chiefs of Police, imposed by the Fifth Amendment. Maryland. 242. Newmark, N. M., Planning and Design of Tall Bombing incidents covered by the public Buildings, State-of-of-the-Art Report No. 7, media as well as those incidents reported di- Technical Committee No. 8: Fire and Blast, rectly to the National Bomb Data Center by University of Illinois, Urbana, September participating agencies are summarized. Bomb- 1971. ing incidents are statistically broken down according to type, i.e., explosive or incendi- The effects on buildings of external loadings ary, number of casualties, damage, geographic of a transient or impulsive nature arising region, known or suspected motive or intent, from the detonation of explosives, including type of devices and fillers, target location gas or other sources, from sonic boom from and state. Also included in the report is a aircraft, or from accidental impact are dis- chronological summary of reported incidents. cussed. Fundamental relations for develop- are 239. Morton, J., Davies, S. R., and Hendry, A. W., ing blast resistance design procedures The Stabilitv of Load-Bearing Brickwork also presented based upon the work of New- Structures Following Accidental Damage to a mark and others. Major Bearing Wall or Pier, Proceedings 243. Paris Suburb Blast Kills 6, Hurts 107. The New Second International Brick Masonry Con- York Times, New York, December 22, 1971. ference, British Ceramic Research Association, 276-281. 1971, pp. An explosion in a 12-story apartment The authors have investigated the possibility building in Argenteuil, France blew out all of a progressive collapse in a number of the interior walls of the first six floors. high-rise and low-rise brick structures. The Officials counted 6 dead and 107 injured, 45 said assessment was made on the basis that, after seriously. Firemen in this Paris suburb local failure of one-load-bearing member, other the blast was apparently due to accumulated structural members must provide an alterna- gas. tive path of support. This alternative path Prestressed Concrete brought into play either the strength of the 244. PCI Design Handbook. floor slab or the bearing support supplied by Institute, Chicago, 1971. an orthogonal wall. A number of situations A comprehensive design guideline (with which could be critical and which would re- examples) of recommended procedures for quire investigation are outlined and methods design and detailing of prestressed concrete of calculating the stability of the structure structures. The Handbook has extensive ma- are described. terial on connections in both frame and bear-

240. Morton, J. P. and Persinger, G. S., Bombing in ing wall prestressed concrete construction for the United States, July 1970-June 1971, The gravity and lateral loads. While progressive National Bomb Data Center, International As- collapse is not specifically mentioned, many sociation of Chiefs of Police Inc., Gaithers- of the details suggested for ductility for earth- burg, Maryland, 1971. quake design seem applicable.

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245. Pipeline Accident Report. Colonial Pipeline To show that overloading risks are com- Company Petroleum Products Pioeline, Jack- mon to traditionally built and prefabricated sonville, Maryland, Report No. NTSB-PAR- buildings alike, three examples of violent ex- 71—2, National Transportation Safety Board, plosions in conventionally built structures are Washington, D.C., December 1971. given. Recommendations are given concerning requirements regarding overloads and A pipeline leak occurred in the Colonial detailing to ensure capacity to withstand such Pipeline System near Jacksonville, Maryland. overloads. Contractors worked continuously for 20 h to find the leak, and on the next day an explosion 250. Recommendations Internationales Pour Le Cal- occurred followed by a fire. There were no cul Et L'Elxecution Des Ouvrages En Beton fatalities, but five workmen were burned. (International Recommendations for the Cal- culation and Execution of Concrete Con- 246. Pipeline Accident Report. Mobil Oil Corpora- struction), Comite Europeen du Beton, Re- tion High-Pressure Natural Gas Pipeline, Near sistance to Accidental Actions, Venice, Oc- Houston Texas, Report No. NTSB-PAR-71- tober 1971. 1, National Transportation Safety Board, Washington, D.C., July 1971. The object of this annex is to define the conditions under which it is possible to look A 14-in pij>eline carrying natural gas at a for an improvement of safety in building pressure of more than 780 psig. ruptured in construction with regards to "accidental ac- a residential subdivision north of Houston, tions." Accidental actions being defined as Texas. All residents were evacuated, and unpredictable loads i.e., gas explosions, acci- etc. for re- about 8 tt) 10 min later, the escaping gas dental impact of vehicles, Means exploded violently. Thirteen houses, ranging ducing or limiting the risk of such accidental from 24 feet to 250 feet from the rupture, actions is presented, and special recommenda- were destroyed by the blast. The leaking gas tions are presented for large panel construc- caught fire and burned for 1% h until valves tion. on either side of the leak were closed by 251. The Resistance of Buildings to Accidental Dam- workmen. In all, 106 houses were damafired, age, RP/ 68/05, Institution of Structural Ens^- and property damage was estimated at $500,- neers. The Structural Engineer, Vol. 49, No. 000. 2, February 1971, p. 102.

247. Pipeline Accident Report. Phillips Pipe Line The recommendations of the Institution of Company. Propane Gas Explosion, Report Structural Engineers for structural design of No. NTSB-PAR-72-1, National Transpor- buildings which are presently covered by the tation Safety Board, Washington, D.C., March Building (Fifth Amendment) Regulations 1971. 1970 are discussed. The recommendations stress joint continuity requirement and fear A rupture occurred in the Phillips Pipeline that the Fifth Amendment regulation will lead Company system in Franklin County, Mis- to unnecessary structural strength and cost. souri, which released 4,538 barrels of pro-

pane. An explosion, equivalent to 100.000 252. Rivard, J. B., Risk Minimization by Optimum pounds of TNT, and a fire resulted in exten- Allocation of Resources Available for Risk sive property damage within a 2 mile radius. Reduction, Nuclear Safety, Vol. 12, No. 4, No fatalities occurred, but ten persons sus- July-August, 1971. tained injuries. The report summarizes the findings of the subsequent investigations. A quantitative approach to system safety has been developed. The risk from compo- 248. Portion of Garage Collapses during Concrete nent activities are expressed as explicit func- Placement, Engineering News-Record, March tions of the resources available for their re- 25, 1971, p. 14. duction, and the minimum system risk is then found by dynamic programming. Nu- A newly placed portion of a three-story merical examples of the method are given. reinforced concrete parking garage collapsed The approach is explained in terms of the in Arlington, Va. Workmen were placing con- nuclear safety problem, but application to

crete for a 20X20 ft slab, and when it gave other fields of risk is straightforward. way, 3,600 ft^ of adjacent concrete slabs also

feU. 253. Rodin, J., The Partial Collapse of a Prefabri- cated Large Panel Tall Building in London 249. Problems of Overloading, LN News (Larsen Its Cause and Consequences, CIB Symposium

Neilsen Building System) , Gotenborg, Sweden, on Tall Buildings, Moscow, October 12—15, No. 46, December 1971, pp. 4-7. 1971.

34 The background leading to the adoption of bearing wall was removed at ground level to large panel systems for tall blocks of flats test the stability of the structure in a damage and the selection of one such system for condition, as might occur following an inter- Ronan Point, part of a major housing proj- nal explosion. Measurements were made of ect in London, is reviewed. The collapse is the applied loads, deflections and strains. The briefly described and the findings of the Pub- theoretical conclusion that the structure would lic Inquiry reviewed in relation to the major, remain stable under these conditions was con- points of principle which arose. The ensuing firmed and some information was obtained problems, the chosen methods of dealing with concerning the strength of 114 mm (4.5 inj them and reactions of the interested parties, thick wall panels subjected to lateral loadings. are reported. The paper includes a suggested design philosophy, particularly related to tall 257. Sinha, B. P., Maurenbrecher, A., and Hendry, buildings, for dealing with hazards, including A. W., Model and Full-Scale Tests on a Five- gas explosions, on a probabilistic basis, in Story Cross-Wall-Structure under Lateral keeping with modern concepts of structural Loading, British Ceramic Research Associa- design. Its application will require more in- tion, Proceedings Second International Brick formation which, hopefully, will be forth- Masonry Conference, Stoke-on-Trent, 1971. coming from certain research projects at present in progress in the United Kingdom. The work described is concerned with the rigidity of, and stress distribution in, a sec- 254. Sharpe, R. L., and Kost, G., Structural Re- tion of multi-story cross-wall structure. Tests sponse to Sonic Booms, Journal Structures were first carried out on one-sixth-scale model Division, ASCE, Vol. 97, No. ST4, April clay brickwork and deflections measured un- 1971, pp. 1157-1174. der lateral loading were compared with those obtained by existing analytical solutions. The A review of field tests with aircraft-gen- latter did not yield accurate results, but an erated sonic booms indicates that properly approximate method based on the calcula- designed and constructed houses should not tion of deflections, story by story, appeared incur damage from sonic booms with nom- more promising. The experiments were re- inal peak overpressures of 2 of 3 psf. Re- peated on a full-scale structure. The test site sponse can be predicted adequately if the and the results of lateral loading tests are de- characteristics of the boom and structure scribed. Comparisons are made between the elements are known. Most damage incidents one-sixth-scale test and the full-scale tests and involve glass damage. also with the results of deflection calculations by the approximate method, by the con- 255. Shinawaga, T., Strength and Behavior of Ver- tinuum method and by a finite element an- tical Joint in Precast Reinforced Concrete alysis. On the whole the full-scale test results Wall Construction, Seminar under the Japan- give substantial confirmation of the model US Cooperative Science Programs, Construc- test. tion and Behavior of Precast Concrete Struc- tures, Seattle, August 1971, p. 223. 258. Slack, J. H., Explosions in Buildings—The Be- Concrete Frames, Con- The results of experiments on the strength havior of Reinforced Vol. No. April 1971, of vertical connections and their behavior are crete, London, 5, 4, pp. 109-114. described. A cast-in-place joint which is called a "wet joint" is used for the vertical Two instances of explosions in reinforced connection with vertical shear forces between concrete factory buildings are discussed. The precast concrete wall panels being transmitted first case study is concerned with an explo- by shear keys in the "wet joint." The vertical sion in a 4-story cast-in-place framed struc- connection used in the structural design of a ture, while the second illustrates the nature of 5-story building was based upon the results blast damage within a single-story precast of this investigation. concrete framed building. In the cast-in-place structure the progression of the explosion 256. Sinha, B. P., and Hendry, A. W., The Stability is traced and the resulting of a Five-Story Brickwork Cross-Wall Struc- pressure wave the external cladding as well as ture Following the Removal of a Section of a damage to described. The precast con- Main Load-Bearing Wall, The Structural En- fire damage are crete frame building suffered column damage gineer, Vol. 49, No. 10, October 1971, pp. 467^74 due to the confinement of the primary explosion. In both of the buildings, large areas of Three experiments are described that had cladding, or their connections, were weaker the objective of confirming that a simple than the main structural frame, resulting in five-story brick cross-wall structure could limited overall damage to the buildings. From remain stable after a section of the main load the first case, it appears that the framed

35 cast-in-place structure had a greater inherent 261. Taylor, N., and Alexander, S. J., Structural resistance to damage than would be indicated Damage by Explosions (A Pilot Survey), by a straightforward analysis taking account Technical Note 22, Construction Industry Re- of structural continuity. In the precast frame search and Information Association, London, structure, it was found that a precast frame England, June, 1971. can have a greater resistance to collapse than would seem apparent from a basic reinforced A pilot survey was initiated to establish

concrete design analysis. However, it is Slack's the procedures for future and wider surveys recommendation that full or partial continuity on the frequency of gas explosions and the at the cast-in-place joint be provided to give structural damage they cause. Newspapers individual members greater resistance to were used to obtain reports of explosions in damage. residences and, where appropriate, visits were made to damaged properties and comprehensive investigation of the circumstances 259. Special Study of Risk Concepts in Dangerous carried out. Findings that gaseous Goods Transportation Regulations, Report show explosions in domestic buildings Great No. NTSB-71-1, National Transportation in Britain causing significant structural damage occur Safety Board, Washington, D.C., January 1971. at the rate of less than one per week. 262. Thomas, K., Structural Brickwork—Materials Examination of the salient approaches un- and Performance, The Structural Engineer, derlying the development of the existing regu- London, Vol. 49, No. 10, October 1971, pp. lations for the transportation of dangerous 441-450. goods; description of the difficulties created

thereby; and discussion of the needs which Calculated loadbearing brickwork is dis- must be met by new approaches are covered. cussed and the basic requirements are speci- The study includes an example of a type of fied. Materials and their effects on strength framework which might be employed for ef- and performance are considered and recom- fectively guiding the risk identification, risk mendations made. The mechanism of brick- evaluation, and risk reduction processes ad- work failure under vertical and lateral load- dressed to the transportation of dangerous ing is covered and the results of current re- goods. search in this field are included. Factors affecting strength are discussed and information is provided on composite action with concrete 260. Stability of Modern Buildings, The Institution beams, also quality control. of Structural Engineers, London, England, September 1971. 263. Third Annual Report of the Secretary of Trans- portation on the Administration of the Nat- The report is largely concerned with high- ural Gas Pipeline Safety Act of 1968, De- rise construction in steel and concrete and partment of Transportation, Washington, with relatively new types of building struc- D.C., July 1971. tures in which members are connected by some form of virtual hinge, and the lateral Refer to annotation for the Second Annual stability of the structure depends generally Report; April 1970 (25). This report is the on stiffening shear walls rather than on the yearly compilation for the calendar year stiffness of the joints in structural frame. In- 1970. dustrialized forms of building composed of prefabricated components are also included. 264. Two Killed and 26 Injured in New Rochelle Ex- The report is presented in two parts: plosion, The New York Times, New York, (1) The first part is concerned with the December 30, 1971. design of modern highrise building structures in steel and concrete. In- An explosion and fire leveled a two-story cluded in this section are: criteria for auto sales and service building and destroyed stability, the box-frame and the precast an adjoining structure on the main thorough- box-frame. fare of New Rochelle, New York. It was re- (2) The second part deals with many types ported that at least two men were killed and of defects and failures that commonly 26 others were injured. The cause of the fire occur in the widest range of these has not yet been determined, but fire offi- forms of construction. Included in this cials said that a boiler in the building might section are: joints in precast concrete, have exploded. single-story shed buildings, eccentric loading, foundations, erection precau- 265. U.S. Capitol Survives Bombing with Light Dam- tions, and common causes of structural age, Engineering News-Record, March 11, distress. 1971, p. 11.

36 Fifteen to 20 lb of dynamite detonated in mitted to a building frame, and the influence the U.S. Capitol building did only minor of support conditions and other geometric damage. Heavy masonry interior walls ab- factors were obtained from the tests. sorbed the force to cushion the blast. The bombing disproved earlier reports that the 269. Alexander, S. J., and Taylor, N., Field Observa- west wall was in imminent danger of col- tions of Gaseous Explosions in Buildings fa

lapse. report based on the CIRIA survey ) , Notes Reference No. 356/72, Building Research Sta- 266. Viaduct Falls on Busy Intersection, Engineering tion Symposium-Buildings and the Hazard News-Record, November 25, 1971, p. 12. of Explosion, Garston, England, October 18, 1972. A 402-ft three-span section of concrete viaduct under construction fell on busy streets The Construction Industry Research and in downtown Rio de Janeiro, killing at least Information Association (CIRIA) began a 24 persons. At the time of the accident, a 2.5 survey in April, 1971 covering damage to ton transit mixer carrying about 8 tons of buildings from all accidental causes, covering concrete was rolling out on the 161-ft center the whole of Great Britain. This paper con- span. The span split near the middle, right centrates on gaseous explosions since they ac- under the truck and collapsed in a V-shape. counted for the majority of the more severe Two adjacent spans followed, falling almost incidents. It deals with the frequency of inci- intact as columns gave way (for additional dents, an evaluation of the severity of inci- details see 275, 308, and 360). dents, and descriptions of several incidents.

267. West, H. W. H., A Note on the Resistance of 270. Allen, D. E., and Schriever, W. R., Progressive Glass Windows to Pressures Generated by Collapse, Abnormal Loads, and Building Gaseous Explosions, Fourth Symposium on Codes, Structural Failures: Modes, Causes, Load-Bearing Brickwork at the Mount Roval Responsibilities, ASCE National Meeting on Hotel, British Ceramic Society, London, 1971. Structural Engineering, Cleveland, Ohio, Ap- ril 1972, pp. 21^7. Tests were carried out involving the eflFect of gas explosions on windows of various de- A brief discussion and 19 dramatic photo- tails in order to study their effectiveness in graphs of progressive collapses of various providing venting. Specimens included sinsle- types of structures that were initiated by local glazed windows of 32 oz glass and double- failure due to abnormal loads. Some statis- gleized units of the same thickness of glass. tics are also included based on a study of Because of their higher strength, the double- news reports, and building code provisions on glazed windows provided ineffective venting. progressive collapse are reviewed briefly. Further, the resistance of glass to short-term 271. Armer. G. S. T., and Kumar. S., Tests on As- loads (defined as lasting 3 s) is more than semblies of Large Precast Concrete Panels, twice that under sustained loadings. Re- Precast Concrete, Vol. 3. No. 8, September peated explosions that do not break glass may 1972, 541-546. be the cause of eventual failure at a lower pp. pressure. The strength of glass decreases with This paper describes an investiffation com- time. For example, glass 18 months old prising tests on twenty-eight half-scale as- failed at loads some 20 percent less than those semblies of precast concrete large panels. The obtained with newly-manufactured glass. Fi- object of this investigation was to study the nally, while the failure of glass may give an behavior of such assemblies after the no- indication of the pressure developed in a real tional removal of certain load-bearing ele- incident, care is necessary in interpreting test ments. The paper concludes with a brief dis- results since a distortion of the frame can cussion of the problem of designing this cause the glass to break at a pressure less form of construction with the aim of reduc- than its actual breaking strength. ing the danger of progressive collapse.

268. Wilton, C, Gabrielsen, B., and Morris. P.. Struc- 272. Beck, H., Stability in the Design of Tall Con- tural Response and Loading of Wall Panels, crete Buildings, Theme Report, Technical URS Report 709-11, URS Research Com- Committee 23, ASCE-IABSE International pany, California, July 1971. Conference on Tall Buildings, Preprints: Re- ports Vol. III-23, August 1972, pp. 1-16. This report is a continuation of a comprehensive investigation of the response to The fundamentals of stability are reviewed rein- blast loading of full scale wall panels fabri- with emphasis on the special effects of methods cated from brittle materials, notably non- forced concrete behavior. A survey of reinforced brickwork. Information such as for calculating the stability of columns, shear element failure times, energy or impulse trans- walls, and precast systems is presented. Some

37 . .

design recommendations and research needs pendix treats the subject of "Partial Stability" are also discussed. in which a building suffers local damage with probable restriction in use, but without com- 273. Bomb Summary, Uniform Crime Reports, Fed- plete collapse. The basic principles of a design eral Bureau of Investigation, National Bomb procedure for "partial stability" based on Data Center, 1972. catenary and membrane action are outlined (for discussion see The data concerning bombing incidents 279) are divided into sections and charts, including bombing incidents by target, by region, 277. Despeyroux, J., Commentary on Structural geographic division and stage, and by ap- Standards for Concrete Structures, Theme parent motive. Also included are selected in- Report, Technical Committee No. 20, ASCE- incidents involving bombing attacks directed lABSE International Conference on Tall against the law enforcement community. Buildings, Preprints: Report Vol. Ill—20, August, 1972, pp. 7-27. 274. Brakel, J., List of Limit States, State-of-the-Art Report 2, Technical Committee 26, ASCE- Though based upon modern safety concepts lABSE International Conference on Tall and recent advances in the field of concrete Buildings, Preprints: Reports Vol. Ill—26, construction, the existing codes for concrete August 1972, pp. 21-59. structures do not generally take into account the specific problems brought up by the tall- A comprehensive list of the various limit ness of buildings. Current design and execu- states of reinforced concrete structures is pre- tion practices make up for this lack of speci- sented. An example would be rupture of criti- fications. They prove to be very likely to re- cal sections of a structure (progressive col- sult in a consistent base for future standard- lapse). Each of the limit states is discussed ization. Modern safety concepts are reviewed, in detail and information is given on perti- special attention being paid to the problem nent literature reference. of the resistance of tall buildings to accidental loadings and progressive collapse. As what 275. Builder Punished Before Collapse Probe Ends, concerns designs problems, tall structures Engineering News-Record, March 9, 1972, differ from the lower ones bv the fact that p. 13. the loadings due to such actions as wind, or Punitive action was taken against ^he con- earthquakes have to be determined taking tractor in the recent Brazilian bridge col- into account the dynamic properties of the lapse. The firm was prohibited from all state structures, and that new types of loadings, sponsored construction work. Investigation ordinarily neglected, due to elastic shortening, indicates the box girder was not yet post- shrinkage, creep and temperature, may ap- tensioned at the time of the collapse. In pear. Second order effects become of primary addition, the government charged many un- importance. Repetition of alternating loadings authorized openings were cast in the slab may have an unfavorable influence on the (see 266) behavior of the structures. Execution of works also needs specific standardization, mainly in 276. Creasy, L. R., Stability of Modern Buildings, the field of tolerances and quality control. The Structural Engineer, London, Vol. 50, Some special techniques present points that No. 1, January 1972, pp. 3-6. are worth considering for Codes of Practice.

The first part of the "Stability" report deals Blast with the basic "anatomy of stabilitv" of tall 278. Detailed Findings on Fatal Steam Pipe buildings and traces the application of this Withheld, Engineering News-Record, New principle to many types of concrete and steel York, July 13, 1972, p. 11. construction. This appraisal is also extended to some other types of buildings to illustrate A 16 in diameter steam pipe burst in the Cor- the application of this basic concept of sta- 36th floor offices of the General Utilities 1972. bility in this fundamental way. The second poration in New York City on May 4, part of the report reviews a number of funda- It was reported that seven office workers died mental aspects of sound design which are com- in the blast. Initial reports suggest that failure mon to most types of building structures and occurred at bellows-type expansion joint and often overlooked. Many of these are con- that the steam inside, used to power air con- the building cerned with the relative movement of the dif- ditioning compressors located on ferent parts of the foundation and superstruc- roof was at 155 psi and about 500°F. ture. Suggestions are made on the provisions which should be incorporated into the original 279. Discussion on the Stability of Modern Buildings, design so that these movements can be safely The Structural Engineer, London, Vol. 50, accepted by the structure in service. An ap- No. 7, July 1972, pp. 275-288.

38 . .

A series of discussions are presented which that destroyed a home and injured 13 per- deal with the paper Stability of Modern sons. It was not clear whether the contractor Buildings by L. R. Creasy (see 276) had been informed of the location of the gas line. 280. Dragosavic, M., Research on Gas Explosions in Buildings in the Netherlands, Notes Reference 285. Ferahian, R. H., Buildings: Design for Pro- No. 354/72, Symposium on Buildings and gressive Collapse, Civil Engineering, ASCE, the Hazards of Explosion, Building Research February 1972, pp. 66-69. Station, Garston, England, 1972. Unusual loads, with some emphasis on gas Summarizes research programs conducted explosions and the danger of progressive col- in the Netherlands to determine the level of lapse in tall buildings made of precast con- pressure to be expected in explosions due to crete elements, are discussed, and design rules pockets of gas in typical buildings. Points out used in Great Britain, France and Canada that the danger of progressive collapse is one are reviewed. due to the overall structural design rather than the design of single members. 286. Fourth Annual Report of the Secretary of Trans- portation on the Administration of the Nat- 281. Dragosavic, M., Structural Measures to Prevent ural Gas Pipeline Safety Act of 1968, United Explosions of Natural Gas in Multi-Story States Department of Transportation, Office Domestic Structures, Scientific Institute for of Pipeline Safety, Washington, D.C., 1972. Building Materials and Structures (In col- laboration with Committee B16a of Stichting Refer to the annotation for the Second An- nual Report, April 1970 (see 183). This re- Bouwresearch) , Delft, Netherlands, February 1972. port is the vearly compilation for the calendar year 1971. Part A of this report summarizes the possible measures to take in order to prevent the 287. Gas Leak Probes Set, Engineering News-Record, collapse of a building after a natural gas ex- March 30, 1972, p. 3. plosion. The execution and results of tests A recent natural gas explosion which de- involving natural gas explosions in buildings stroyed two homes in Fairfax County, Vir- are described in Part B (see 338) ginia, is prompting new investigations into

282. The Dust Clears at Clarkston. Concrete, London, gas leaks by the National Transportation Safety Board. Vol. 6, No. 1, January 1972, p. 37.

A gas explosion destroyed a row of twenty- 288. Graaf, S., Stabilization of IB at Aldershot. Con- two single story terraced shops in Clarkston, crete, London, Vol. 6, No. 4, April 1972, pp. Glasgow. Below the shops were a series of 30-32. basement voids where gas from a nearbv Details of the strengthening of British broken main seeped and concentrated until Army precast housing buildings to withstand it was ignited. The maximum damage oc- explosive forces. Continuity between floors curred about halfway along the terrace be- and load bearing walls was achieved by low some three or four of the shops. At the drilled-in diagonal anchor pin joints. Ver- location of the explosion, floor slabs were tical tie rods were added to anchor strength- lifted and the collapse of the front row of ened partition walls against uplift. columns implied the failure of 12 inXl8 in reinforced concrete beams and cross beams 289. Granstrom, S. A., The Scandinavian Approach at ground level. to Structural Safetv, Notes Reference No. 358/72, Building Research Station Sympo- 283. Excavator Hits Gap Pipe, Six Die. Engineering sium-Buildinss and the Hazard of Explosion, News-Record, November 9, 1972, p. 21. Garston England, October 18, 1972. A gas explosion in a store in Lake City, Minnesota killed six persons and injured This is a discussion on the draft Swedish collapse; three. Gas leaked into the store's basement Regulation on design for progressive after an excavator operator, working on a its history and a comparison of the draft with building project adjacent to the store, rup- British regulations. tured a medium-pressure gas line. 290. Greider. W., The Economics of Death or. Your 284. Excavator Hits Gas Pipeline; Explosion Rips Life May Not Be Worth Savins. Washington Nearbv House, Engineering News-Record, No- Post, Washington, D.C., April 9, 1972. vember 16, 1972. Author describes the rationale behind the An excavator uprooted a gas line in a cost-benefit analysis of putting a price tag on Minneapolis suburb, causing an explosion human worth, or the price of life and death.

39 ; ;

Also covered are some of the problems eval- (c) if the requirement in (b) is not eco- uators encounter in trying to determine a nomically feasible; so designing the standard means for comparison of all lives. essential structural elements of a building that they can withstand the pressure 291. Illingworth, J. R., Formwork, Civil Engineering developed in the event of a gas ex- and Public Works Review, June 1972, pp. plosion. 581-592. Part B of the report presents an account of 34 tests with explosions of natural gas under A review of current practice in the design extreme conditions such as may occur in a and use of formwork and associated equip- dwelling. Presents pressure measurements and ment is presented and accompanied by a design recommendations. bibliography of 39 references to the more

important published works of recent years. 295. Leach, S. J., and Bloomfield, D. P., Gas Accumu- The article points out that where formwork lation and Ventilation, Notes Reference No. failures occur, the most frequent are those 357/72, Building Research Station Sympo- involving falsework. In most falsework fail- sium-Buildings and the Hazard of Explosion, ures, inadequate consideration of falsework Garston, England, October 18, 1972. design usually results in a progressive col- The influence of buoyancy on the dilu- lapse of the falsework itself with catastrophic tion by ventilating air of accidental leaks of results. toxic and flammable gas is discussed and the 292. The IRA and the Structural Engineer, Euro- limiting cases, where buoyancy effects are pean Scientific Notes, Office of Naval Re- negligible and where they dominate, are theo- search, London, March 1972, pp. 71—72. retically investigated. Theoretical results are tabulated and presented on design charts for The bombing of an Army Officer's building controlling gas hazards in buildings by ven- in Aldershot near London in February 1972 tilation for a wide range of practical situa- is described. The Irish Republican Army tions. claimed to have carried out the bombing using 280 pounds of gelignite. The building 296. Lewicki, B., and Pauw, A., Joints. Precast Panel did not collapse. The walls of one-half of the Buildings, ASCE-IABSE International Con- building were blow away completely, but the ference on Tall Buildings, Lehigh University, structural frame of reinforced concrete re- 1972, Proceedings, Vol. Ill, pp. 171-189. mained intact. This discussion of design considerations for joints and connections in precast concrete 293. IRA Bomib Kills 8, Including Bombers, Wash- structures stresses the importance of tensile ington Post, Washington, D.C. August 23, continuity and joint ductility in large precast 1972. panel buildings. The importance of tie and peripheral bond beams in developing floor A 100 lb bomb, which apparently exploded and wall diaphram action is emphasized. De- prematurely, destroyed a customs station in sign recommendations for floor and wall joints Newry, Northern Ireland on August 22, 1972. and for minimum reinforcement requirements The bomb killed eight persons, including the in tie beams and tensile continuity connec- two Republican guerrillas who planted it. tions are included. 294. Konstruktieve Maatregelen Tegen Aardgasexplo- 297. MacGregor, J. G., Stability of Reinforced Con- sies In Hoge Woongebouwen (Structural crete Building Frames, State-of-Art-Report 1, Measures Against Explosions of Natural Gas Technical Committee 23, ASCE-IABSE Inter- in Multistory Residential Buildings), Rapport national Conference on Tall Buildings, Pre- NR:BI-72-6/04.3.02.520, Institut TNO Voor prints : Report Vol. III-23, August 1972, pp. Bouwmaterialen Bouwconstructies, Delft, En 19-35. February 1972. The behavior of reinforced concrete frames Research was undertaken to determine the is reviewed, followed by a review of theoreti-, possibilities of preventing explosions of nat- cal analysis of the stability of elastic, elasto- ural gas in multi-story residential buildings plastic, and reinforced concrete frames. Ap- or of limiting the effects of explosions. The proximate methods and design recommenda- structural measures whereby this can be tions are presented concerning frame stability. achieved comprise:

(a) the prevention of gas leakage 298. Mainstone, R. J., Internal Blast, State-of-the-Art (b) ensuring that a wall or floor which Report 6, Technical Committee 8, ASCE- fails as a result of pressure due to an IABSE International Conference on Tall explosion will not cause progressive Buildings, Preprint: Reports Vol. lb-8, collapse August 1972, pp. 127-141.

40 Recent studies of the nature and structural 302. Odgaard, A., and Olesen, S. 0., Local Failure in effects of internal blast are reviewed. High- Panel Buildings. A Discussion Illustrated by explosive blast is distinguished from that due a Model Test. Byggeteknisk Konstruktions- to a gaseous deflagration, and the main em- forsknings Central, Report No. 017/B47, phasis is on the latter since this has been the Denmark, September 1972. most widespread cause of local and sometimes more widespread structural damage The report contains the description and the under peacetime conditions in recent years. results of a project which consisted in the Both the possibility of limiting the peak pres- construction and testing of a 4-story concrete sures reached by means of venting and the large panel building in the model scale 1:4. design of structural elements and complete Questions concerned with the concepts of structures to resist the blast are considered. local failure and progressive collapse have A final comment is made on codes of prac- been examined. Generalizations are made to tice and regulations. extend the test results into design recommendations.

299. Mainstone, R. J., The Effects of Explosion on 303. Palmer, K. N., Explosions Research at the Fire Buildings, Notes Reference No* 352/72, Research Station, Notes Reference No. 353/ Building Research Station Symposium, Build- 72, Building Research Station Symposium- ings and the Hazard of Explosion, Garston, Buildings and the Hazard of Explosion. Gars- England, October 18, 1972. ton, England, October 8, 1972.

The report covers the following: sources, The paper outlines research pertaining to characteristics and incidence of internal blast, the problem of explosions in buildings and control of peak pressures, and design of struc- the design requirements that should be laid tural elements and the structure as a whole down. to withstand internal explosion and resist progressive collapse. 304. Popoff, A. Jr.. Designing Against Progressive Collapse, PCI Design Seminar, October 1972. 300. Marosszeky, M., Construction Loads Imposed The paper includes a survey of the Regula- in Multi-Story Structures, Civil Engineering tions adopted by Britain, France. Canada Transactions, Australia. Vol. CE14, No. 1, and the United States following the Ronan April 1972, pp. 91-93. Point failure. In Appendix C, Designing Against Progressive Collapse, the author de- A simple analysis is presented for evaluat- scribes the minimum reinforcement and the ing the severity of construction loads in a minimum connections which he feels every multistory structure built of in situ concrete. precast building should have. Where the upper floors are supported by the lower floors, the construction loads can be 305. Popoff, A. Jr., Stability of Precast Concrete reduced sufficiently to make them less critical Systems Buildings. ASCE-IABSE International than the service loads when floors are re- Conference on Tall Buildings, Lehigh Univer- leased an dallowed to self carry their weight sity, 1972, Proceedings, Vol. HI, pp. 571- before the next floor is poured. 583.

review of existing and emerging regula- 301. Nissen, Henrik, Industrialized Building and A tions for preventing progressive collapse in Modular Design, Cement and Concrete Asso- a precast concrete systems building points ciation, London, 1972. out the need for continuous wall and slab reinforcement, and indicates that this can be The book deals with general subjects in provided at nominal cost. It suggests the the field of industrialized building and mod- adoption of design principles similar to those ular designs and shows how the principles used for earthquake design. For precast sys- have been applied to actual projects in Den- tems, the design of joints is of prime im- mark. The whole range of prefabricated con- portance. Eighteen references and excerpts struction is covered; the design examples in- from British Regulations to prevent progres- clude four apartment buildings, one terraced sive collapse. house, three one-family houses, two schools, one office and one factory. The building sys- 306. Possible Hazard. Engineering News-Record. May tems discussed include those usins brick- 25. 1972, p. 13. work, concrete, wood and steel. Extensive treatment of force transmitting connections The author of Building Construction for including typical details and test results for the Fire Service warned officials of fire de- connection and tie systems for precast and partments that formwork fire in a post-ten- load bearing units are included. sioned concrete building under construction

41 could result in a "catastrophic total collapse" 312. Special Study of Systematic Approach to Pipe- that would bring "terrible casualties to fire- line Safety, Report Number: NTSB-72-1, fighting forces." He cites possibility of a pro- National Transportation Safety Board, Wash- gressive collapse engulfing firemen fighting a ington, D.C. May 1972. form fire on an upper story. This study describes what system safety is, 307. Remainder of Collapsed Building Demolished, what its potential benefits are, and some of the by which it applied to Engineering News-Record, July 27, 1972, p. methods may be 11. safety in the pipeline field. For example, by using the systematic approach to safety, pipe- The remaining one-third of the 16-story re- line accidents can be predicted and analyzed inforced concrete apartment building that before they occur. Accidents can then be pre- collapsed while under construction in Boston vented by taking the action necessary to elim- in January, 1971 was demolished because it inate or control the hazards which lead to the was "structurally unsound and unsafe" and incidents. the structure contained "questionable concrete." The $5-million building, of flat plate 313. Strehlow, R. A., Unconfined Vapor Cloud Ex- design, incurred a progressive collapse of plosions—An Overview, Report AAE TR 72- two-thirds of its slabs and columns when a 1, UILU-ENG. 72 0501, Aeronautical and shear failure occurred around a column at Astronautical Engineering Department, Uni- the roof slab and the roof slab fell. versity of Illinois, Urbana, Illinois, February 1972. 308. Report Blames Viaduct Collapse on Sloppy Work. Engineering News-Record, January The explosion of unconfined vapor clouds 27, 1972, p. 10. produced by the dispersion of flammable liquid or vapor spills is becoming a serious An investigating committee reported that problem, mainly due to the increased size of the collapse of a 402-ft three-span section of the spills in recent years. This paper surveys concrete viaduct under construction in Rio accidental explosions that have occurred over de Janeiro resulted from mistakes and omis- the past 40 years and also evaluates recent sions in design and construction (see 266). research efforts which pertain to the dispersion and explosion of large vapor clouds. 309. Sanders, P. H., Evaluation of the Risk of Ve- hicle Impact on Structures, Structural Fail- 314. Structural Safety—A Literature Review. Journal ures: Modes, Causes, Responsibilities, ASCE Structural Division. ASCE, Vol. 98, No. ST4, National Meeting on Structural Ensineering, April 1972, pp. 845-884. Cleveland, Ohio, April 1972. pp. 87-98. A literature review and bibliography con- A method of statistical aralveis is proposed taining 351 references is provided as a guide for determining the probability that an ex- for structural engineers interested in studying terior ground-floor column in a multi-story the problem of a structural safety. The re- building will be struck by a motor vehicle view is divided into five sections treating straying from its normal traffic path. load analysis, strength analysis, dvnamic structural analysis, structural reliability an- 310. Sertion of Bui'ding Collapses During Razina;, alysis, and design aspects. Ene^neering News-Record, March 30, 1972, p. 3. 315. Summary of Liquid Pipeline Accidents Reported on Dot Form 7000-1 from January 1. 1971, The center section of a V-shar»ed. eiffht- through December 31, 1971. Office of Pipe- story department store in downtown Kansas line Safety, Denartment of Transportation, City, Missouri collapsed during razing of the Washington, D.C, March, 1972. structure. The collapse occurred while workers were using acetylene torches on the first Liquid Pipeline accidents reported to the floor of the steel framed structure. The City Department of Transportation are summar- charged demolition contractor violated citv ized. Data include the location, number and codes which call for buildings to be razed percentage of accidents which occurred, com- from the top down. modities involved, deaths, injuries, and value of property damage sustained, cause of acci- 311. Spanish Explosion, Washington Post, Washing- dent, and location of accident by state. ton, B.C., March 7, 1972. 316. Sutherland, R. J. M., Structural Design of A 10-story apartment building in Bar- Masonry Buildings, ASCE-IABSE Interna- celona, Spain was reported to have suffered a tional Conference on Tall Buildings, Lehigh violent explosion on the fourth floor. All floors University, 1972, Proceedings, Vol. HI, pp. of one comer of the building collapsed. 1035-1055.

42 While the advantage of masonry is economy 320. West, H. W. H., Load-Bearing Brickwork Under without visual or planning monotony, the Explosion Loading, Notes Reference No. 355/ most obvious limitation is structural per- 72, Symposium on Buildings and the Hazards formance. Only if all conditions are favor- of Explosion, Building Research Station, able, is it possible to build 25 to 30 stories Garston, England, 1972. high in unreinforced load bearing masonry. The use of masonry is discussed in relation This paper describes gas explosion experi- to national codes from the viewpoints of sta- ments undertaken by the British Ceramic Re- bihty, earthquakes, explosions and other search Association from 1969 to 1972. Sim- accidental damage. Future developments are ulating conditions in typical upper stories of noted. a cross-bearing wall apartment building, typical concentrations of natural and town gas were ignited. measured pressures 317. Swinnerton, H. A., An Ancient Form of Energy Maximum were around psi in almost all realistic Adapted to Modern Practice, Civil Engineer- 3^/2 cases although one test in an unvented room ing and Public Works Review, April 1972, induced pressures of 5 psi. This was felt to pp. 387-389. be nontypical. This article reviews several aspects of the 321. Wilton, C, and Gabrielson, B., Shock Tunnel demolition industry, including advantages ob- Tests of Wall Panels, Technical Report, URS tained by the explosives in the past and the future. 70 30—7, Vol. 1, Test Information and An- alysis, URS Research Company, San Mateo, 1972. 318. Tall Building Criteria and Loading: Fire and California, January Blast, Technical Committee 8. ASCE-TABSE Test information and analytical results for International Conference on Tall Buildings, a varietv of reinforced brick, concrete block Lehigh University, 1972, Proceedings, Vol. and clay tile wall geometries subjected to lb, pp. 463-746. blast loads, and for short statically loaded beams are presented in Volume 1. Non-pre- A series of reports and discussions preloaded solid walls tested stronger than pre- senting the state of the art of designing and dicted. Preloading with the equivalent of one construction tall buildings so they can safely or two stories added only 10 to 20 percent to resist fire and blast loadings. wall strength. Walls with doorwavs and with windows behaved as predicted, with concrete 319. Wakabayashi, M., Frames Under Strong Im- block walls beina; very weak comparatively. pulsive, Wind or Seismic Loading, State-of- Interior walls of hollow clay tile and concrete the-Art Report 6, Technical Committee 15, block failed at very low overpressures. ASCE-IABSE International Conference on Tall Buildings, Reports Vol. 11—15, August 322. Wing of Completed Apartment Building Col- 1972, pp. 95-115. lapses. Engineering News-Record, November 2, 1972, p. 12. A general review is given on the behavior and design of structural frames and their One wing of an eight-story reinforced con- components under strong impulsive loadings, crete building collapsed in Buenos Aires. Pre- such as an internal or external explosion, liminary investigation indicates that concrete and wind or seismic loadings. The main quality and placement of reinforcing bars characteristics of these loads are first dis- may have fallen short of requirements. An cussed in relation to structural behavior, em- eyewitness said the building "slid down like phasizing the problems of ductility, energy a ball of cream," destroying some ground absorption capacity, P-delta effect and pro- floor stores and an automobile service station. gressive plastic deformation. As the second Some settlement and cracking of columns in step of the discussion, the behavior of beams, the structure had been noted. columns, beam-columns, braces, connections is and frames under monotonic loading dis- 323. Witteveen, J., Philosophy of Risks and Accept- cussed by introducing theoretical and exper- able Damage and Indications for Desim, imental studies. The dynamic plasticity prob- Technical Committee 8: Fire and Blast. ASCE- lems of the structure due to impulsive load IABSE Joint Committee-Planning and Desisn and the behavior of frames and their compo- of Tall Buildings, Proceedings of the 6th nents under repeated loading are discussed. Regional Conference. Delft, The Netherlands. Several examples of the application of hyster- May 15, 1972, pp. 35-38. etic characteristics to dynamic analysis are shown, and finally a reference is made to the Accounts of building failures in the Nether- problem of progressive plastic deformation lands for one year showed that, in most cases, in the plastic design to tall buildings. structural damage was caused by extreme

43 situations as fire and blast and that in many so that they hold under certain specified acci- cases failure of a relatively minor structural dental loads, or load damage, and prevent part, or a fire in a relatively unimportant progressive collapse. Test results lead to pre- room, initiated a catastrophe that led to con- liminary expressions for determining joint siderable consequential structural damage. To strength and adequacy for reducing risk of answer the question "Is there a 'limit of progressive collapse. growth' of tall buildings due to these prob- of Panel Structures, lems?" it is necessary to establish a logical 328. The Behavior Large Con- philosophy on the risks and the acceptable struction Industry Research and Information damage and to develop a more adequate cal- Association, London, Report 45, March 1973. culation method to evaluate these factors. The report gives the findings of a two-part These are elaborated in the article. study which examined the local behavior of shear transfer and compression transfer 324. Aged Hotel Falls After Structural Defect Cited, joints, and which also determined the most Engineering News-Record, August 9, 1973, efficient means of analyzing walls composed p. 12. of large panels. As a result of the experi- One-third of an 8-story, 105 year old hotel mental study, empirical formulae, for more collapsed in New York City, four weeks after efficient design, have been proposed, while the hotel had been cited for unrepaired struc- computer programs have been produced for tural work. The structure is of brick and elastic and elasto-plastic analysis of panel wood construction. shear walls taking into account the slip between panels. 325. Allen, D. E., and Schriever, W. R., Progressive Collapse, Abnormal Loads, and Building 329. Blast Rips a Sears Tower Neighbor, Engineer- Codes, Structural Failures: Modes, Causes, ing News-Record, September 6, 1973, p. 16. Responsibilities—a compilation of papers 19- printed at the ASCE National Meeting on A gas explosion that ripped through a Structural Engineering, Cleveland, Ohio, story reinforced concrete building in Chicago April 1972. published by ASCE, New York, also smashed 65 to 70 glass panels in the 1973. 1,450 ft high Sears Tower across the street from the explosion scene. The explosion Examples of progressive collapse that buckled 6 to 10 in walls and floors in the have occurred in the past and of abnormal building, and also collapsed stairwells. How- collapse loads which can initiate progressive ever, the building was still structurally sound are given. Statistics are also included based and did not have to be razed. on a study of news reports, giving a rough measure of existing situations susceptible to 330. Blast Strikes Skyscraper, Engineering News- progressive collapse. Building Code provi- Record, November 15, 1973, p. 16. sions on progressive collapse are reviewed briefly. One worker was killed and 19 others injured last week when a short circuit trig- 326. Armer, G. S. T., Current Research at BRS on gered a fire and explosion in the 31 -story the Stability of Precast Concrete Panel Struc- Northern Trust Company Building under tures, Reference No. 388/73, DOE/CIRIA construction in Chicago. Seminar The Stability of Precast Concrete Engineering Structures, London, March 27, 1973. 331. Bombers Harass Building Sites, News-Record, August 16, 1973, p. 3. This paper describes the program of tests three being carried out at the Building Research Police last week removed homemade construc- Station (En2;land) aimed at discovering pipe bombs from widely separated modes of failure of a three-story, four-bay tion sites in New York City. Nine bombs panel structure under uniform loading with have been found or have exploded at city variations in the support conditions which building sites since January 1. simulate loss of panels due to explosion. 332. Burnett, E. F. P., Abnormal Loadings and the Safety of Buildings, Report Prepared for: 327. Baker, A., and Yu, C, Research to Investigate Section, National Bureaus of the Strength of Floor-to-Outside-Wall Joints Structures Washington, D.C., August 1973. in Precast Concrete, Reference No. B387/73, Standards, DOE/CIRIA Seminar, The Stability of Pre- The objective of this report is to attempt cast Concrete Structures, London, March 27, to identify and classify all forms of loading 1973. that can influence a building. In particular, The purpose of the research was to provide those forms of loading that by current design test data for the design of floor-to-wall joints standards may be presumed to be abnormal.

44 will be categorized and their significance con- precast concrete construction have been stud- sidered. Types of loading treated in detail ied to try to obtain some general impressions include: explosive bombing; natural gas ex- of the current state of practice, and some plosions; aircraft accidents; and sonic boom detailed impressions of the specific form of effects. joint studied.

333. Burnett, E. F. P., Somes, N. F.. and Leyen- 337. Cracknell, C. J., and Jamnan, D. A., Effect of decker, E. V., Residential Buildings and Gas- Heavy Impact Loads on Structural Members, Related Explosions, NBSIR 73-208, (June Concrete, London, Vol. 7, No. 8, September 1973). 1973, pp. 49-50.

The findings of an analysis of available A design procedure is outlined (with

USA statistics concerning the frequency of worked examples I for the impact loading that gas-related explosions in residential build- occurs on a reinforced concrete beam when ings are presented. The study was confined to a load fails under gravity from a medium incidents involving piped gas systems as they height that the damage caused to the struc- affect residential and commercial buildings. tural member is similar to that of a very Though due regard has to be taken of the heavy static load. limitations inherent in the available statistics, 338. Dragosavic, M., Structural Measures Against it is concluded that in the USA the prob- Natural-Gas Explosions in High-Rise Blocks ability of occurrence of an explosion capable of Flats, Heron, Vol. No. 1973, 51 of causing significant structural damage could 19, 4, pp. be 2.2 per million housing units per year. English translation of entry 281.

334. Collapse Kills Five and Destroys Large Portion 339. Excessive Horsepower Drops Former Stable, of 26-Storv Buildins: Under Way, En2:ineer- Bjigineering News-Record, September 27, ing News-Record, March 12. 8, 1973, p. 1973, p. 13.

A form failure, a structural failure or a A possible overload and unauthorized al- climbing crane collapse killed at least five terations may have been responsible for the workers and destroyed a large section of a collapse of a four-story brick and timber 26-story cast-in-place reinforced concrete building in New York City that was con- apartment building under construction in verted in 1918 from a stable to a garage. Bailey's Crossroads, Virginia. The weight of the falling climbing crane, the green concrete 340. Explosions Take Heavv Toll, Engineering News- and the cured 8 in thick floor slabs, ripped Record, March 1, 1973, p. 3. an 80 ft wide top-to-bottom gap in the build- Report of three explosions involving gas ing. Two completed decks of an adjacent leaks or pipeline ruptures including an apart- parking garage also collapsed. (For more de- ment building. tails see 335, 374, 349, 350, 347, 361, 362.) 341. Explosives Complete a Partial Collapse, Engi- 335. Collapse Blamed on Premature Shoring Re- neering News-Record, December 13, 1973, p. moval, Engineering News-Record, April 19, 12. 1973, p. 11. Explosives knocked down the rest of the The possible premature removal of shoring partially collapsed concrete shell roof of a between the 22nd and 23rd floors of the 26- bulk materials storage building 4-64 ft long, story building in Bailey's Crossroad appar- by 105 ft wide by 100 ft high. Two panels ently caused tbe progressive collapse of a por- collapsed at one end of the building and ex- tion of the cast-in-place reinforced concrete plosives were needed to drop the roof in a structure. The finding was contained in a con- way that would not destroy or damage the sultant's report to be presented to a grand columns and concrete walls, which rise only jury. about half the building's height.

336. Colman, D. G., An Investigation of Joints in 342. Failures at Two Schools Spur Concern for 100 Frameworks, Reference No. B389/73, DOE/ Others of Similar Design, Engineering News- CIRIA Seminar, The Stability of Precast Con- Record, July 5, 1973, p. 10. crete Structures, London, March 27, 1973. Bearing failures at end of a precast joist This paper covers the precast concrete part triggered a progressive collapse of the entire of a pilot study commissioned to look at a roof according to investigating officials. Bear- limited range of joints, both in precast con- ing surfaces were very narrow (1.5 in) and crete and in structural steel construction. typical of details used in a large number of Eight different forms of steel insert joints for structures.

45 . .

343. Fatal Pipe Installation Engineering News- 347. Guilty in Collapse, Engineering News-Record, Record, November 8, 1973, p. 3. July 19, 1973, p. 16.

The collapse of a portion of a 105 year old A Virginia state court found a concrete hotel in New York City (see 324) was at- subcontractor guilty of misdemeanor charges tributed to an apparently unauthorized in- stemming from the March collapse of a 26- stallation about 30 years ago of a drain pipe story apartment building under construction in a bearing wall. A crack in the pipe rein a Washington, D.C. suburb (see 334). sulted in a leak that weakened the mortar of the brickwork. 348. Hughes, B. P., Limit States of Impact and CPllO, Concrete, London, Vol. 7, No. 8, 344. Fribush, S. L., Bowser, D., and Chapman, R., August 1973, pp. 37-40. Estimates of Vehicular Collisions with Multi- story Residential Buildings, NBSIR 73-175, Relative to the recent Fifth Amendment of (April 1973). the British Standard CPllO, an examination is made of the essential requirements and as- Through analysis of data from Oklahoma sumptions which can be made to facilitate and Illinois along with national statistics, simple design for exceptional events, espe- estimates are made of the number of ve- cially limit states of impact. It is demonstrated hicular collisions with buildings on an an- that for all normal designs where the simpli- nual, nation wide basis. The best estimate fied stability clauses are followed, a satis- is on the order of tens of thousands. However, factory resistance to accidental damage is as- since the impetus for the study was on multi- sured. Includes 2 examples of calculation story buildings and the likelihood of their of recommended tie forces to satisfy CPllO. being subject to progressive collapse, the calculations have been refined to apply to sub- 349. Indicted Subcontractor also Faces OSHA Ac- stantial damage to multistory residential tion, Engineering News-Record, May 21, 1973, buildings. In 1970, such accidents were only p. 13. on the order of 40, hence the probability of a apart- given building being so affected in a single The concrete subcontractor for the that collapsed at Bailey's Cross- year is approximately one in ten thousand. ment building charged with willful violation Some discussion is provided on improvement roads, has been for data collection for the future. of the Occupational Safety and Health Act (OSHA). Charges alleged that the contractor 345. Fortskridande ras (Design to Avoid Progressive was responsible for the premature removal of

Collapse) , The National Swedish Board of forms, failure to properly conduct tests to Urban Planning, Publication No. 63, July 1, insure concrete strength was sufficient for 1973. form removal, and use of damaged shoring materials (see 334) The National Swedish Board of Urban Ranning has worked out regulations regard- 350. Indictment Against GC on Collapsed Building ing the stability of buildings in order to re- Dismissed, Engineering News-Record, June duce the risk of progressive collapse due to 14, 1973. p. 15. local damage. The regulations are divided into mandatory requirements and recommen- The general contractor for the 26-story dations with solutions deemed to satisfy apartment building that collapsed in March the requirements. In connection with the while under construction in a Washington, regulations, some commentary is published. D.C, suburb has been cleared of charges The regulations are supplements to Chapter made by a grand jury. The judge determined 21 (section :93) and Chanter 22 (section :35) the contract made the concrete subcontractor in Svensk Byggnorm (SBN). responsible. A consultant hired by the county says the collapse was caused by the premature 346. Granstrom, S., Stability After Local Damage, Re- removal of shoring (see 334) port of research in Sweden, CIB W23A, Copenhagen, September 4, 1973. 351. Inexperience Hurts. Engineering News-Record, November 15, 1973. p. 3. Summarizes current Swedish philosophy regarding acceptable risks in multi-story con- Collapse of a three-story garage in New struction. Summarizes principal causes of York City (see 324) was caused by an three progressive collapses in Sweden (pro- $80,000 alteration job performed by an in- pane explosions, solvent explosions, fire). Dis- experienced contractor who did not consult cussed social effects of risk analysis and com- with an architect or engineer. Alterations pares to statistics regarding death by fire, included replacement of 500 wood floor drowning, and suicide. beams, installation of a new roof of corru-

46 gated metal decking and 4 in. of reinforced Conference, New England College, Henniker, concrete topped by 1.5 in of asphaltic con- N.H., July 22-27, 1973. crete. The life span of structures is determined 352. Insurance Facts 1973, Insurance Information by design, construction, functional service- Institute, New York, 1973. ability or environment as natural causes of demise. This paper deals with such topics as The booklet includes a ten year U.S. prop- the life cycle of structures, structural design, erty insurance catastrophe record and indi- fire, insurance and rehabilitation of bridges. cates type of catastrophe and magnitude of loss. 357. Litle, W. A., Boston Collapse (a summary paper). Structural Failures: Modes, Causes, Re- 353. Janney, J. R., Structural Failures, Structural sponsibilities—a compilation of papers printed Failures: Modes, Causes, Responsibilities, at the ASCE National Meeting on Structural ASCE National Meeting on Structural Engi- Engineering, Cleveland, Ohio, April 1972, neering, Cleveland, Ohio, April 1972, pp. published by ASCE, New York, 1973. 11-20. The paper outlines the conditions and de- A brief discussion of several case histories tails of the January 25, 1971 collapse of a where failures have occurred due to gravity 16-story reinforced concrete apartment build- loads. The discussion is divided into failures ing under construction. Also included is a caused by ponding, bearing problems, shear summary of a report by the five-man investi- and stability. A plea is made that more doc- gating commission appointed by the mayor to umentation on such failures should be pub- probe the collapse. lished.

358. Mainstone, R. J., The Hazard of Internal Blast 354. Lewicki, B., Deuar, K., and Zieleniewski, S., In- in Buildings, Building Research Establish- teraction of Floor and Wall for Prevention of ment Current Paper, CP 11/73, England, Progressive Collapse in Large Panel Build- April 1973. ings, International Council for Building Re- search Studies and Documentation—Working Recent studies of the nature and structural Commission 2A, Meeting at Copenhagen, Sep- effects of internal blast are reviewed. Hish tember 1973, printed by Centre for Building explosive blast is distinguished from that due Systems Research and Development, Warsaw. to a gaseous deflagration, and the main emphasis is on the latter since this has been the The interaction of bearing walls and most widespread cause of local and sometimes floors in large panel buildings can reduce to more extensive structural damage under a large extent the risk of a progressive col- peacetime conditions in recent years. Both lapse. An initial theoretical study on this the possibility of limiting the peak pressures problem is presented suggesting a method of reached by means of venting and the design calculation for panel structures with elements of structural elements and complete structures removed. Authors outline needed testing pro- to resist the blast are considered. A final com- gram on panels and joints. ment is made on codes of practice and regulations. 355. Leyendecker, E. V.. and Fattal. S. G., Investi- gation of the Skvline Plaza Collapse in Fair- P., Bombing Incident Target An- fax County, Virginia, NBSIR 73-222, (June 359. Morton, Jane 1970 December 1971, Interna- 1973). alysis, July — tional Association of Chiefs of Police, Gaith- The progressive collapse of the Skyline ersburg, Maryland, 1973. Plaza apartment building A—4 at Bailey's During the period July, 1970, through De- Crossroads, Virginia (see 333) has been cember, 1971 a total of 2.889 bombing inci- studied by using information contained in dents were recorded by the lACP based on case records of the Occupational Safety and data gathered from field reports and the regu- Health Administration (OSHA), U.S. De- screening of 11,000 daily and weekly news partment of Labor and obtained from on-site lar publications. The incidents in this publica- inspections by investigators from the Na- tion have been placed into fourteen major tional Bureau of Standards. Non-compliance categories with various sub-categories and with OSHA construction standards has been analyzed to evaluate the significance of the identified with regard to formwork, field- targets being attacked. The analysis includes cured concrete specimens and crane installa- the frequency of incidents directed against tion. each target, the kind of bomb employed, the 356. Life Span of Structures, Report of Observations motive or intent of the bomber, and the geo- targets. In of Attendees at the Engineering Foundation graphical and regional location of

47 . . a,

addition, a chronological siunmary listing of 365. Richtlinien und Bestimmungen der neuen DIN bomb incidents for each target category is 1045 fur GroBtalelbauten (Directives and presented. specifications of the new German standard DIN 1045 for large-sized constructions) 360. Not Guilty, Engineering News-Record, Septem- Betonwerk and Fertigteil-Technik, Vol. 1, ber 13, 1973, p. 16. 1973. (In German, with English and French The court of justice of Guamabara, Brazil, summary pp. 5—14.) has absolved the president of Sobrenco Con- DIN 1045 contains no summarized section struction Company, five engineers and five of specifications for large-sized slab construc- state inspectors of criminal responsibility in tion. Although the new specifications for pre- connection with the collapse of a 402 ft sec- cast reinforced-concrete constructions are tion of concrete viaduct under construction summarized in section 19 previously DIN in Rio de Janeiro on November 20, 1971 (see — 4225—the specifications for large-panel slab 266). constructions have to be compiled from vari- further sections. This article compiles and 361. Not Guilty, Engineering News-Record, October ous explains, based on the specifications of the 4, 1973, p. 32. new DIN 1045 for large-sized slab construc- A job superintendent was acquitted of in- tions, the completed "Tentative specifications voluntary manslaughter in the building col- for constructions of large sized wall and floor lapse that killed 14 construction workers. The panels." judge ruled that the prosecution did not con- clusively prove that the defendant prema- 366. Rules and Regulations Relating to Resistance to turely ordered removal of shoring from be- Progressive Collapse under Extreme Local neath the 23rd floor of a planned 26-story Loads, Housing and Development Admin- reinforced concrete building in Bailey's Cross- istration, Department of Buildings, The roads, Virginia (see 334) City Record, New York, August 2, 1973.

Amendment of the City of New York Build- 362. OSHA Makes a Deal. Engineering News-Record, ing Code to require resistance to progressive November 22, 1973, p. 15. collapse by either the alternate path method The concrete subcontractor for the Bailey's or the specific local resistance to 720 psf Crossroads building agreed to pay $13,000 method. in federal penalties without admitting guilt in OSHA violations (see 334) 367. Sahlin. S., and Runesson. K., Nagra Berakningar Av Kraftomlagring MMI Cellstruktur, Chal- 363. Partially Collapsed Building Repaired, Engineer- mers University of Technology. Institute for ing News-Record, January 25, 1973, p. 26. Building, Report 73:12, July 1973.

Repairs have been completed on Ronan Report presents results of a detailed finite Point, a 24-story London apartment build- element type analvsis of a three storv bearing ing that partially collapsed in 1968. The wall structure with typical door and window article mentions that this failure possibly re- openings. Various structural configurations duced enthusiasm for systems building in are assumed based on loss of key panel and England. The article notes that subsequent corner elements. Results are presented in to the Ronan Point collapse, the government terms of forces and deformations with key checked 2,000 high-rise buildings of more elements removed. than six stories and of these, 700 required strengthening. 368. Sanders, P. H., Evaluation of the Risk of Ve- hicle Impact on Structures, Structural Fail- 364. Peterson, Hans, Analysis of Building Structures, ures: Modes, Causes, Responsibilities— Chalmers University of Technology, Depart- compilation of papers printed at the ASCE ment of Building Construction, Report 1973: National Meeting on Structural Engineering, 11, Goteborg, 1973. Cleveland, Ohio, April 1972, published by ASCE, New York, 1973. The work summarized in this paper deals with the structural analysis of multi-story The failure of an exterior ground-floor col- buildings. Two methods, the finite element umn in a multi-storv building would cause method and the stringer method, are used. collapse at every level of those floor areas that The finite element technique is applied to the depend upon the failed column for support. bending and in-plane analysis of plates. The This paper deals with the probability of a analysis is further extended to the evaluation motor vehicle striking an object located near of the response of multi-story buildings to a traffic path. This probability is shown to be static loads. Experimental results for slabs a function of the distance of the object from and wall joints are also presented. the traffic path and the volume of traffic.

48 — .

369. School Roof Collapse Blamed on Short Ledge, buildings to progressive collapse, and pro- Cross Ties. Engineering News-Record, August posed mandatory requirements for the struc- 23, 1973, p. 14. tural design of high-rise buildings to be constructed under HUD programs. The British Building Research Establish- ment cited several reasons for the collapse 373. Structural Failures: Modes, Causes, Responsibil- last June of a school's assembly hall roof in ities, A compilation of papers presented at London. These include insufficient bearing the ASCE National Meeting on Structural area, insufficient cross ties, corroded rein- Engineering, Cleveland, Ohio, April 1972 and forcement, strength loss due to use of high published by ASCE, New York. 1973. alumina cement (conversion) and lack of continuity. The book contains seven papers which relate directly to structural failures. 370. Somes, N. F., Abnormal Loading on Building 374. Two Firms, Individual, Indicted as Result of and Progressive Collapse, NBSIR 73-221, (May 1973). Fatal Collapse, Engineering News-Record, May 3, 1973,' p. 16. This report attempts to define the param- Indictments have been returned against the eters of the problem of progressive collapse, general contractor, the concrete subcontractor to classify and discuss the various sources of and the subcontractor's job superintendent in abnormal loading and to quantify their fre- connection with the accident at Bailey's Cross- quency insofar as the currently available U.S. roads (see 334) data permits. The implication of these findings for the USA are then discussed. The re- 375. Weeks, G. A.. Tests on the Public Building sponse of buildings and building elements to Frame at BRS, Reference No. B390/73, DOE/ abnormal loading is then reviewed, including CIRIA Seminar, The Stability of Precast Con- cases of progressive collapse. Several alterna- crete Structures, London, March 27, 1973. tive approaches for the introductions of criteria are presented and, finally, conclusions are The Department of the Environment has given with respect to the problem posed in adopted a standard system for precast con- the USA. crete frame construction for use within the Public Sector. Previous structural experi- 371. Steele, W. A. Bowser. D., and Chapman. R. E., mentation associated with this development The Incidence of Hazardous Material Acci- has been limited to tests on individual com- dents During Transportation and Storage, ponents and isolated joints. This paper de- NBSIR 73-412 (November 1973). scribes some aspects of an experimental program, including tests to failure, carried out This report is one of a series describing in the Structures Laboratory at the Building background research concerning the incidence Research Station on a full-scale two-story of abnormal loading. The report is organized assembly built in this way and should be in terms of modes of hazardous material treated as an interim document. Test results transportation and storage. These modes indicated substantial geometric effects which pipeline, water, motor vehicle, and railroad influenced stability which would not have transportation systems—are addressed in been noted in isolated joint tests. four sections with Storage Systems discussed

in a fifth. The sections depend on the amount 376. Wilford, M. J., and Yu, C. W., Catenary Action of available data, rather than the risk in- in Damaged Structures. Reference No. B391 / volved in an accident. A summary of the re- 73, DOE/CIRIA Seminar, The Stabilitv of sults is presented in the last section. On the Precast Concrete Structures, London, March whole, there is little empirical evidence to 27, 1973. substantiate a threat to buildings from haz- The Structural Engineer is now required to ardous materials transport. However, trends design a structure against the possibility of in volumes shipped in proximity to structures complete disaster following local damage. of interest raises the prospect of future in- Many of our current forms of construction cidents. have this capacity, but there is no recognized to calculate for this 372. Structural Design Requirements to Increase Re- design data on which possibility. This paper attempts to establish sistance of Buildings to Progressive Collapse, and prove a design procedure based on Proposed HUD Handbook by the HUD Staff, action of the U.S. Department of Housing and Urban De- "catenary" and "membrane" members, to produce a state of velopment, November 1973. structural "partial stability." The report summarizes This draft document reflects the state-of-the- tests on beam and slab specimens with sup- art for methods to increase the resistance of ports removed to determine collapse state

49 load capacity. Results indicated special de- contact writh research workers in other coun- tailing is generally required to ensure cate- tries working in this field, but is not included nary action. in the English edition. The second stage consisted of a survey of claims for damage in 377. Wilhelmsen, A. M., and Larsson, B. Sonic Booms Sweden in an attempt to clarify the extent to and Structural Damage, D3/1973 (Statens which it was possible to judge whether dam- institut for byggnadsforskning) Stockholm, , age could be caused by sonic booms. The third May 1973. stage comprised a test series of overflights The study of the effects of sonic booms was over test units. Data and conclusions are pre- performed in three stages. The first stage sented which indicate sonic boom is not a comprised a survey of the available literature threat to primary structural members if on the effect of sonic booms on buildings and planes are flying above 1000 m.

50 3. Author Index D

Numbers refer to references, which are numbered consecutively. Dansk Ingenjorforening 126 Davies, S. R 239 Department of the Environment—London 241 A Despeyroux, J 103, 104, 277 Deuar, K 354 Dobbs, N 164 ACI Committee 342, 67 Donahue, Adams, H. C 194 J. D 161 Dowding, C. H 215 Alexander, S. J 95, 147, 261, 269 Dragosavic, M 280, 281, 338 Allen, D. E 195, 270, 325 Allgood, J. R., 148 American Gas Association 170 Amerongan, C. V 68 E Ames, S 182 Amirikian, A 3 Edge, P. M., Jr 27 Anderson, B. G., 9 Edmunds, J. 145 Armer, G. S. T 271, 326 Edwards, A. T 22 Arthur D. Little, Inc 61 Expert Council of the Danish Society of Engineers 125 ASCE 17

ASCE-IABSE Technical Committee on Tall Buildings . 8, 318 Astbury, N. F 196, 197 F ' Au, T. Y 227

Fattal, S. G 355 Federal Civil Defense Administration 7 B Feld, J 26, 46, 79 Ferahian, R. H 217, 285 Firnkas, S 18, 108, 109 Baker, A 327 Flak, H 167 Baker, J. F 1 Foster, D 201 Battat, M. E 179 Fribush, S. L 344 Bechtel, S 145 Fry, J. F 219 Beck, H 272 Beresford, F. D 33 Birkeland, H. W 40 Birkeland, P. W 40 G Blakey, F. A 33 Bloomfield, D. P 295 Gabrielsen, B 145, 268, 321 Boston Mayor's Investigation Commission 203 Gas of France, et al 65 Bowser, D 344, 371 Gifford, R. W 222 Bradshaw, R. E 201 Glassman, A 110 Brakel, J 274 Godfrey, K. A 82 British Standards Institution 175 Goffin, H 83 Brondum-Nielsen, T 202 Graaf, S 288 Brook, D. H 8 Granstrom, S. A 10, 171, 223, 224, 225, 289, 346 Burhouse, P 59 Greater London Council 178, 189, 190 Burnett, E. F. P 332, 333 Greenfield, F. C 172 Greider, W 290 Griffiths, H 84 c Grundy, P 21

California Department of Justice 199 H Carlsson, M 225 Chandler, S. E 25 Hambly, E. C 95, 147 Chapman, R 371 344, Hamilton, W. A 99 Clare, R 197 Hanson, K 112 CIB Commission W23, 216 Haseltine, B. A 113, 227, 228 Cohen, E 164 9, Hawkins, N. M 237 Coles, B. C 99 Hellers, B. G 167 Collins, A. R 100 Hendry, A. W 239, 256, 257 Colman, D. G., 336 Hodgkinson, A 173 Comite Europeen du Beton, 68, 250 Hodgkinson, H. R 196, 197 Connell, K. F 77 Hoglund, T 167 Construction Industry Research Information Association Holmgren, J 167 (CIRIA) 218, 328 Holtum, R. D 172 Cotton, P. E 4 Hughes, B. P 348 Cousins, E. W 2, 4 Cracknel], C. J 337 Crawford, R 22 I Creasy, L. R 159. 160, 210, 276 Cubbage, P. A 197 Cubbitt, R. L 179 Ulingworth, J. R 291 Custard, G. H 161 Institution of Civil Engineers 226 Cutler, J. F 211 Insurance Information Institute 352 Cziesielski, E 44 International Association of Chiefs of Police 238

51 J p

Janney, J. R 353 Paddleford, D. F 121 Jarman, D. A 337 Palmer, K. N 182, 303 Pauw, A 296 Persinger, G. S 240 K Petersson, H 364 Plewes, W. G 195, 211 Kabaila, A 21 PopofI, A., Jr 304, 305 Kalra, J. C 172 Porl, M. K 53 Kanoh, Y 231 Power, J. K 30 Kost, G 254 Prestressed Concrete Institute 244 Kumar, S 271 Pugsley, A 84

L R Ramsay, W. A 31 Larsson, B 377 Rasbash, D. J 127, 182 Lax, D 1 Reese, L. C 87 Leach, S. J 295 Rivard, J. B 252 Leggatt, A. J 176 Robinson, J. R 69, 129 Legget, R F 16 Rodin, J 130, 253 Lewicki, B 354 50, 232, 233, 296, Rogowski, Z. W 182 Leyendecker, E. V 333, 355 Rozvany, G. L N 132 Ligtenberg, F. K 116, 234 Runesson, K 367 Litle, W. A 357 Russoff, B. B 55 Lohrding, R. K 179 London Ministry of Housing and Local Government 80, 124 Lugez, J 117, 235 s

Sahlin, S 367 M Saillard, Y 133 Sanders, P. H 309, 368

MacGregor, J. G 297 Saunders, 0. 84 Mainstone, R. J 236, 298, 299, 358 Schriever, W. R 16, 195, 270, 325 Marchand, P. E 51 Shapiro, G. A 23 Marosszeky, M 300 Sharpe, R. L 254 Mast, R. F 118 Shell International Gas Limited 104 Matlock, H 87 Shinagawa, T 255 Mattock, A. H 237 Short, A 134 Maurenbrecher, A 257 Short, W. D 71 Mayes, W. H 27 Sinha, B. P 256, 257 McKaig, T. H 19 Slack, J. H 258 Mikluchin, P. T 211 Smith, R. B 77 Miles, J. R 134 Sokolov, M. E 23 Ministerio del Lavorio Publici 120 Somerville, G 59 Monk, C. B., Jr 13 Somes, N. F 333, 370 Morris, P 268 Soviet Economic Mutual Aid 165 Morton, J 239 Stanger, R. H. H 38 Starr, Morton, J. P 240, 359 C 135 Statens Planverk 212 Steele, W. A 371 N Strehlow, R. A 313 Stretch, K. L 137 Sutherland, R. National Industrial Conference Board 5 J. M 316 Swihart, G. R 148 National Research Council of Canada 177, 155 Swinnerton, H. 317 National Swedish Board of Urban Planning 345 A National Transportation Safety Board 122, 180, 185, 230, 245, 246, 247, 259, 312 T Newberry, C. W 28, 66 Newmark, N. M 11, 242 Taylor, N 261, 269 New York Department of Buildings 366 Teichmann, G. A 12 Nielsen, K 6 Thayer. J. R 161 Nissen, H 301 The Institution of Structural Engineers 86, 93, 111, 153, 260 Nordic Sub-Committee on Large Concrete Panels 186 The Technical Advisory Panel on Explosion Research 142 Norris, C. H 14 Thomas, K 113, 228, 262 Northwood, T. D 22 Thompson. N. F 2 Turner, R. D 179 o u Odgaard, A 302 Office of Naval Research—London 292 U.S. Department of Housing and Urban Development 372 Olesen. S. 0 112, 302 U.S. Department of the Air Force 140 Ostenfeld, C 35 U.S. Department of the Army 63, 140 Ota, Y 231 U.S. Department of the Navy 140 Otway, H. J 179 U.S. Department of Transportation 183, 263, 286, 315

52 w c

Wakabayashi, M 319 Canadian code—see Building code, Canadian Weeks, G. A 375 Catenary action 210, 272, 376 West, H. W. H 196, 197, 267, 320 Chain reactions—see Failure modes West-water, R 8, 12 Code—see Building code Whitney C. S 9 Collapse 130 Wiggins, J. H 144 Collapse, construction 71, 72, 203, 248, 266, 270 Wilford, M. J 376 C^ollcipsc fire see Fire Wilhelmsen, A. M 377 Collapse', multiple examples .19, 26, 71, 79, 110, 167, 223, Williams, E. L 1 225, 249, 270, 325, 353, 370, 373 Wilton, C 145, 268, 321 Collapse, Aldershot 292 Witteveen, J 323 Collapse, Argenteuil, France 336 Woods, J. F 132 Collapse, Arlington, Virginia 76, 85, 248 Collapse, Atlanta, Georgia 36

Collapse, Bailey's Crossroads, Virginia . . 334. 335, 347, 349, 350, 355, 361, 362, 374 Collapse, Barcelona, Spain 311 Yamanouchi, 0 231 Collapse, Boston, Massachusetts 200, 203, 204, 205, 206, 307 357 Yu, C 327, 376 209 213 229 Collapse, Brazil 207, 208, '266,' 275,' 308,' 360 Collapse, Brooklyn, New York 39 Collapse, Buenos Aires 96, 149, 181, 322 Collapse, Cairo 24 Zarzvcki, A 117 Collapse, Dayton, Ohio 106 Zieleniewski, S 354 Collapse, Godthaab, Greenland 156, 22 Collapse, Harrisonburg, Virginia 15 Collapse, Houma, Louisiana 152 Collapse, Italy 37 Collapse, Jamaica 43 4. Subject Index Collapse, Las Vegas 123 Collapse, Madrid 107 refer to references, are Numbers which numbered consecutively. Collapse, Malaysia 75 Collapse, Manhatten, New York 54, 56 Collapse, Mexico City bridge 70 Collapse, New Orleans, Louisiana 45 Abnormal loading see Accidental impact; Construction loads; — Collapse, New York 191 Explosions; Faulty practice; Foundation failure Collapse, New York City 20, 64, 324, 339, 343, 351 Accidental impact 116, 121, 146, 217, 234, 242, 370 Collapse, Ottawa 32, 41, 47 Accidental impact, aircraft 332 Collapse, Paris 29 Accidental impact, construction equipment 43, 77 Collapse, Pittsburgh, Pennsylvania 48, 157 Accidental impact, frequencies 234, 370 Collapse, Pt. Pleasant bridge 62, 74 Accidental impact, highway vehicles ... 125, 126, 178, 191, Collapse, Ronan Point 73. 78. 80. 84. 88. 89 90. 91. 92. 94, 214, 250, 309, 344, 368 97, 100, 103, 105, 108, 109, 114, 128, 129, 131 Accidental impact, ships 35 Collapse, Scotland 282 Aerial explosions 10 Collapse, Sweden 49, 60 Alternate path 45, 80, 86, 98, 103, 109, 111, 114, 115, 129, CoEapse, Tennessee 192 133, 160, 173, 187, 194, 202, 366, 367 210, 276, 354, Collisions—see Accidental impact Alternate path, tests 210, 223, 224, 231, 239, 256, 271, 302, 326 Column failures 149, 322 Analysis, mathematical 14, 367 Comite Europeen du Beton 104, 250 Analysis, structural see Structural analysis — Comparisons—see Building code, comparison Anchorage 112 Connections—see Joints Construction Joints—^see Joints B Construction loads . . .6, 21, 33, 41, 42. 46. 55, 67, 157, 203, 204, 300, 306, 314, 334 Continuity ... .18, 68, 69, 83, 103, 108, 118, 216. 2.=iT. 2.'^8. 288. Bison system see System building. Bison — 296, 305, 319. 369 Blast resistant design see Structural design, explosions — Corrosion 39. 369 Blasting 12, 22, 215 Costs—see Economic factors Boiler explosions—see Explosions, boiler and steamline Cranes—see Accidental impact Bombing—see Explosions, high explosives Criteria—see Alternate path; Building code; and Specific Bond failure 34 resistance Brick—see Masonry British code—see Building code, British Building code. Agreement 53 D Building code, British ... .80, 81, 84, 89, 90, 93, 97, 100, 101, 134, 138, 175, 216. 222, 348 Danish code—see Building code, Danish Building code, Canadian 155, 177, 195, 211, 217 Debris load 143, 145, 157, 337 Building code, CEB—see Recommendations, CEB Demolition 8, 63. 71, 310, 317 Building code, comparisons 233, 270, 277, 285, 289, 298, Design criteria—see Alternate path; Building code; and Spe- 304, 325, 358 cific resistHiice

Building code, Danish 98, 171 Design interpretations . 86, 111, 113, 153, 159, 160, 163, 166, Building code, HUD 372 178, 189, 195, 241. 348 Building code, Italian 120, 233 Domes 43. 57, 58 Building code, London 178, 189, 190 Dynamic analysis 147, 220 Building code. New York City 366 Dvnamic loading—see Explosions

Biiildina; code, Polish 139 Dynamic tests . 9, 13, 14, 17, 22, 99, 148, 150. 196, 197, 220. Building code, Russian 165. 184, 233 267, 314, 337 Building code, Swedish 186, 212, 223, 233, 289, 345, 346 Dynamite—see Explosions, high explosives

53 E I

Economic factors 119, 135, 176, 201, 214, 251, 290, 305 Ice load—see Snow load Editorials, building regulations 97, 100, 104, 105, 114, 118, Impact (see also Accidental impact) 337 150, 154, 176 In-situ joints—see Joints Editorials, progressive collapse ... 88, 91, 100, 103, 114, 128, Insurance 352, 356 150, 154 Italian code—see Building code, Italian Error, construction—see Faulty practice Error, design—see Faulty practice

Excavation . .32, 64 Explosions, boiler and steamline 25, 264, 278 Joints, In-situ—requirements 118, 319 Explosions, external 125, 126, 140, 214, 217, 234, 371 Joints, In-situ—tests 45 Explosions, gas and vapor .... 94, 122, 125, 126, 152, 156, 169, Joints, Precast elements—design 40, 50, 69, 117, 174, 232, 171, 243, 245, 246, 247, 249, 250, 282, 283, 284, 285, 287, 329, 235, 244, 296, 301, 304, 305, 328 330, 340 Joints, Precast elements—requirements .... 18, 23, 40, 44, 50, Explosions, gas and vapor characteristics 4, — 2, , 95, 127, 53, 55, 59, 68, 69, 84, 108, 109, 117, 118, 249, 260, 296, 304, 137, 142, 147, 162, 182, 197, 218, 220, 269, 280, 281, 295, 298, 305, 319, 327, 336 358 299, 313., 338, Joints, Precast elements—tests 23, 38, 50, 59, 112, 143, Explosions, gas and vapor—control ... .81, 95, 102, 111, 127, 224, 255, 258, 327, 328, 336, 375 137, 147, 193, 194, 294 Explosions, gas and vapor—frequency ... 25. 61, 84, 102, 142 218, 219, 221, 261, 269, 313, 332,333, 370 Explosions, gas and vapor—tests ... 2, 4, 150, 182, 1%, 197, 220, 236, 267, 280 294, 320 Larsen-Neilsen—see System building Explosions, high explosives 1, 125, 126, 171, 198, 242, 265, Lateral forces—see Specific resistance. Tie forces 292, 293, 331 Layout of panel structure 93 Explosions, high explosives—characteristics .1, 3, 5, 8, 10, Leaks—see Explosions, gas and vapor ' 63, 161, 298, 299 317, 358 Limit state 274, 348 Loads see Abnormal loads; Accidental impact; Construction Explosions, high explosives—frequency . . . .223, 238, 240, 273, — 332, 359, 370 loads; Debris loads; Explosions; Snow load; and Tsunamis Explosions, high explosives—tests 22, 99, 150, 164 Explosions, internal 84, 113, 116, 125, 126, 140, 214, 217, M 234. 258, 265, 270, 292, 299, 303., 318, 358 Explosions, liquid oxygen .230 Masonry 13, 32, 64, 111, 113, 129, 137, 152, 194, 196, 197, 201, 211, 226, 227, 228, 239, 256, 257, 262, 316, 320, 321, 343 F Models 22, 164, 224, 257, 302 Failure—see Collapse N Failure modes. Key link 57. 58, 62, 129 Failure modes. Progressive—horizontal .... 15. 20, 26, 29, 34, Natural gas (see also Explosions, gas and vapor) 65 35, 36, 39, 49, 60, 70, 72, 103, 106, 134, 200, 203, 207, 208, Nitroglycerin—Explosions, high explosives 24S. 266, 334, 341, 342, 357, 369

Failure modes. Progressive—vertical . 24, 37, 47, 48, 54, 56, 64, 73, 75, 76, 80, 84, 85, 90, 91, 92, 94, 96, 103, 106, 109, 123, 134, 149, 156, 157, 167, 181, 191, 200, 203, 204, 206, 209, 213, 229, 271, 291, 306, 307, 310, 311, 322, 324, 326, 334, 335, 339, Panels—see Building code; and Joints 351, 355, 357 Panels, design ... .44, 50, 53, 68, 83, 104, 134, 137, 145, 175, Faulty practice. Construction error 26, 29, 32, 37, 41, 47, 217. 235, 250, 354, 365 57, 71, 75, 76, 85, 181, 200, 203, 204, 205, 207, 275, 307, 308, Panels, tests . 23, 143, 145, 168, 197, 228, 231, 255, 256, 310, 322, 334, 335, 347, 349, 350, 351, 355, 360, 361, 362, 37.4 268, 271, 302, 321, 326, 328. 375 Faulty practice, Design error 26, 34, 58, 110, 275, 308 Pipeline accidents—see Explosions, gas and vapor; and Pipe- Faulty practice. Occupant misuse ... .24, 26, 54, 56, 107, 110, line safety 339, 343 Pipeline networks 170 Fifth Amendment (to British Building Regulations) —see Pipeline safety .52, 61, 77, 180, 183, 185, 221, 245, 246, 247, Building code, British; and Recommendations, Fifth 263, 283, 284, 286, 287. 312, 315, 340, 371 Amendment Polish code—see Building code, Polish Fire 25, 102, 110, 116, 234, 242, 306, 318, 323 Precast concrete 18, 23, 36, 40, 50, 53, 55, 59, 73, 82, 83, Flat plate 20, 21, 33, 46, 47, 200, 203, 204, 206. 307, 84, 112, 123, 271, 285, 288, 296, 301, 304, 305, 326, 336, 342, 334, 357 365, 375 Force, tie—see Tie forces Pressure—see Explosions Formwork 6. 21, 33, 46, 67 Prestressed concrete 15, 99, 132, 244, 275, 306 Formwork failure 26, 42, 70, 76, 79, 291, 349 Progressive collapse—see Collapse ; and Failure modes Foundation failure, Adiacent excavation 32, 64 Projectiles 121, 146

Foundation failure. Excessive settlement . 24, 110, 207, 208, 260, 322 Frames—see Rigid frames Frequencies—see Accidental impact; and Explosions Recommendations, CEB 68, 69, 104, 133, 158, 250

Recommendations, CEB, discussion of . . 103, 104, 128, 133, 138, 232, 233

Recommendations, Fifth Amendment . .80, 93, 124, 187, 190, Gass (see also Explosions, gas and vapor) 65 217 Glass 2, 27, 30, 31, 220, 236, 254, 267 Recommendations, Fifth Amendment, discussion of . 84, 86, 97, 101, 103, 114, 115, 129, 133, 143, 151, 153, 159, 160, H 163, 166, 168, 172, 173, 174, 188, 194, 222, 228, 233, 241, 251, 320, 348 High explosives—see Explosion, high explosives Redundancy—see Alternate path Highway vehicles—see Accidental impact, highv^ay vehicles Regulations—see Building code

54 Regulations, gas 65 Structural design, explosions ... .1, 3, 5, 7, 9, 11, 13, 14, 17, Reinforcement, lateral 296, 304, 376 93, 140, 147, 148, 161, 194, 226, 228, 242, 289, 298, 299, 303, Reinforcement, ties 18, 59, 69, 296, 304, 327, 376 304, 318, 319, 358, 376 Repair—see Strengthening Suspended structures 232

Rigid frames, . . . 45, 137, 160, 178, 187, 241, 258, 276, 292, System building 51, 82, 91, 141, 172, 363 297 310 329 330 System building. Bison 143, 168, 222 214, Risk analysis . . .16, 116, 130, 135, 146, 161, 179, '234, System building, Larsen-Neilsen, 249 252, 259, 290, 312, 323, 332, 333, 344, 346, 368 System building, Wates 38 Ronan Point—see Collapse, Ronan Point Roofs 20, 26, 36, 39, 42, 49, 57 Russian code—see Building code, Russian Rusting—see Corrosion Tension failures 39, 192 Test, procedures 143, 354, 375

. . Tie forces . .53, 98, 134, 136, 143, 178, 216, 224, 232, 296, Safety factor 16, 46, 104, 116, 138, 216, 250, 314 301, 348, 369 Sagging 45 Tornadoes 121, 146 Seismic design 244, 305 Traffic—see Accidental impact, highway vehicles Shear, 20, 40, 44, 47, 203, 204, 237, 307, 353, 357 Trusses 39, 62, 129, 192 Ships—see Accidental impact, ships Tsunamis 87 Shoring—see Formwork Snow load 16, 49, 58 Sonic booms 27, 28, 30, 31, 66, 144, 254, 332, 377 Specific resistance ... .80, 86, 98, 111, 115, 143, 154, 168, 187, 202. 294, 320, 366 Vapor explosions—see Explosions, gas and vapor Specifications—see Building code; and Regulations Vehicles—see Accidental impact, highway vehicles Stability 260, 272, 276, 279, 297, 375, 376 Venting ... 2, 4, 95, 127, 129, 137, 142, 162, 182, 193, 197, Stability, Bearing wall structures 170, 260, 305, 343 220, 236, 258, 267, 280, 281, 294, 295, 298, 313, 320, 338, 358 Stability, Damaged structures 126. 216, 239, 256 Viaducts 266. 275, 308, 360 Standards—see Building code: and Regulations Vibrations 12, 22, 28, 64, 215 Statically determinate structures—see Failure mode, Key link Statically indeterminate structures—see Alternate path Statistical design 116. 130, 145, 253 w Steel frames 29, 31, 45, 48, 56, 72, 106, 192, 310 Strength—see Joints; Masonry; and Panels Walls—see Panels Strengthening 80, 90, 136, 172, 188, 226, 288, 363 Welded connections—see Joints Structural analysis 155, 257, 314, 364, 367 Wind bracing 4g Structural analysis, explosions 9, 11, 95, 239 Wind pressure 16, 84, 92, 201, 234 Structural design 93, 111, 113, 118, 195, 201, 210, 225, Windows—see Glass; and Venting 226, 244, 272, 280, 281, 302, 304, 328, 338 Wood 58. 60

•C^ U.S. GOVERNMENT PRINTING OFFICE: 1975 O 592-102

)

NBS--H4A

U.S. DEPT. OF COMM. 1. PUBLICATION OR RHFORT NO. 2. Gov't Accession 3. Recipient's Accession No. B.BL.OGRAPH.C DATA NBS BSS- 67

4. TITLE AND SUBTITLE 5. l-'u bl i <; at ion Date January 1976 Abnormal Loading on Buildings and Progressive Collapse. An Annotated Bibliography 6. Performing Organization Code

7. AUTHOR(S) 8. Performing Organ. Report No. E. V. Leyendecker , J. E. Breen, N. F. Somes, and M. Swatta

9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. Project/Task/Work Unit No. 4618488 NATIONAL BUREAU OF STANDARDS DEPARTMENT OF COMMERCE 11. Contract/Grant No. WASHINGTON, D.C. 20234

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP) 13. Type of Report & Period Office of Policy Development and Research Covered Department of Housing and Urban Development Final - 1974 Washington, D. C. 20410 14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

ijibrary oi Congress Uataiog JNumber: iD-oLyUyo

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.) This bibliography on the subjects of abnormal loading and progressive collapse is an annotated listing of articles that have appeared in the technical literature from 1948 through 1973. The entries have been arranged chronologically by year and alphabetically within years. Both subject and author indexes have been included. The references listed have been selected as most representative of the historical background and best representing the origin and present state-of-the-art of current practice without undue repetition of data. References pertaining to characteristics, frequencies, incidents, tests, design procedures, and regulations for many types of abnormal loadings are included. Among these are various types of accidental impacts, construction loads, explosions, faulty practices, and extreme atmospheric loads. Heavy emphasis was placed on referencing applicable building codes and regulations pertaining to the subjects of progressive collapse and abnormal loadings. This bibliography also contains numerous references to contemporary professional opinion as expressed in editorials and discussions of the subject and, particularly, on the various regulations proposed. A large number of proposed analysis and design procedures, as well as applicable test results, are referenced. In addition to the general reference material, a careful search was made of the ten most recent years (1964-1973) of Engineering News Record to identify and annotate possible progressive collapse examples from building failures reported by that publication. 17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons Abnormal loading; alternate path; annotated bibliography; bibliography; building code; building regulations; collapse; failures; progressive collapse; specific resistance

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PERIODICALS program coordinated by NBS. Program under authority of National Standard Data Act (Public Law 90-396). JOURNAL OF RESEARCH reports National Bureau of Standards research and development in physics, NOTE: At present the principal publication outlet for mathematics, and chemistry. It is published in two sec- these data is the Journal of Physical and Chemical tions, available separately: Reference Data (JPCRD) published quarterly for NBS by the American Chemical Society (ACS) and the Amer- • Physics and Chemistry (Section A) ican Institute of Physics (AIP). Subscriptions, reprints, Papers of interest primarily to scientists working in and supplements available from ACS, 1155 Sixteenth these fields. This section covers a broad range of physi- St. N. W., Wash. D. C. 20056. cal and chemical research, with major emphasis on Building Science Series Disseminates technical infor- standards of physical measurement, fundamental con- — mation developed at the Bureau on building materials, stants, and properties of matter. Issued six times a components, systems, and whole structures. The series year. Annual subscription: Domestic, $17.00; Foreign, presents research results, test methods, and perform- $21.25. ance criteria related to the structural and environmen- • Mathematical Sciences (Section B) tal functions and the durability and safety characteristics of building elements and systems. Studies and compilations designed mainly for the math- Topics in mathe- ematician and theoretical physicist. Technical Notes—Studies or reports which are complete theory of experiment design, numeri- matical statistics, in themselves but restrictive in their treatment of a logical cal analysis, theoretical physics and chemistry, subject. Analogous to monographs but not so compre- computers and computer design and programming of hensive in scope or definitive in treatment of the sub- quarterly. systems. Short numerical tables. Issued An- ject area. Often serve as a vehicle for final reports of nual subscription: Domestic, $9.00; Foreign, $11.25. work performed at NBS under the sponsorship of other government DIMENSIONS/NBS (formerly Technical News Bul- agencies. letin) —This monthly magazine is published to inform Voluntary Product Standards—Developed under pro- industry, teachers, scientists, engineers, businessmen, cedures published by the Department of Commerce in of latest advances in students, and consumers the Part 10, Title 15, of the Code of Federal Regulations. emphasis on the science and technology, with primary The purpose of the standards is to establish nationally work at NBS. The magazine highlights and reviews such recognized requirements for products, and to provide protection, building tech- issues as energy research, fire all concerned interests with a basis for common under- nology, metric conversion, pollution abatement, health standing of the characteristics of the products. NBS and safety, and consumer product performance. In addi- administers this program as a supplement to the activi- tion, it reports the results of Bureau programs in ties of the private sector standardizing organizations. measurement standards and techniques, properties of matter and materials, engineering standards and serv- Federal Information Processing Standards Publications ices, instrumentation, and automatic data processing. (FIPS PUBS)—Publications in this series collectively constitute the Federal Information Processing Stand- Annual subscription: Domestic, $9.45; Foreign, $11.85. ards Register. Register serves as the official source of information in the Federal Government regarding stand- Federal Property NONPERIODICALS ards issued by NBS pursuant to the and Administrative Services Act of 1949 as amended. Public 89-306 Stat. and as implemented Monographs—Major contributions to the technical liter- Law (79 1127), ature on various subjects related to the Bureau's scien- by Executive Order 11717 (38 FR 12315, dated May 11, 1973) and Part 6 of Title 15 (Code of Federal tific and technical activities. CFR Regulations). Handbooks—Recommended codes of engineering and Consumer Information Series—Practical information, industrial practice (including safety codes) developed based on NBS research and experience, covering areas in cooperation with interested industries, professional of interest to the consumer. Easily understandable organizations, and regulatory bodies. language and illustrations provide useful background Special Publications—Include proceedings of confer- knowledge for shopping in today's technological ences sponsored by NBS, NBS annual reports, and other marketplace. special publications appropriate to this grouping such NBS Interagency Reports (NBSIR) —A special series of as wall charts, pocket cards, and bibliographies. interim or final reports on work performed by NBS for outside sponsors (both government and non-govern- Applied Mathematics Series—Mathematical tables, ment). In general, initial distribution is handled by the manuals, and studies of special interest to physicists, sponsor; public distribution is by the National Technical engineers, chemists, biologists, mathematicians, com- Information Service (Springfield, Va. 22161) in paper puter programmers, and others engaged in scientific copy or microfiche form. and technical work.

National Standard Reference Data Series—Provides Order NBS publications (except NBSIR's and Biblio- quantitative data on the physical and chemical proper- graphic Subscription Services) from: Superintendent of ties of materials, compiled from the world's literature Documents, Government Printing Office, Washington, and critically evaluated. Developed under a world-wide D.C. 20402. BIBLIOGRAPHIC SUBSCRIPTION SERVICES

The following current-awareness and literature-survey survey issued quarterly. Annual subscription: $20.00. bibliographies are issued periodically by the Bureau: Send subscription orders and remittances for the pre- Cryogenic Data Center Current Awareness Service ceding bibliographic services to National Technical Information Service, Springfield, Va. 22161. A literature survey issued biweekly. Annual subscription: Domestic, $20.00; foreign, $25.00. Electromagnetic Metrology Current Awareness Service Issued monthly. Annual subscription: $24.00. Send Liquefied Natural Gas. A literature survey issued quar- subscription order and remittance to Electromagnetics terly. Annual subscription: $20.00. Division, National Bureau of Standards, Boulder, Superconducting Devices and Materials. A literature Colo. 80302. U.S. DEPARTMENT OF COMMERCE National Bureau of Standards Washington. D.C. 20234 POSTAGE AND FEES PAID U.S. DEPARTMENT OF COMMERCE OFFICIAL BUSINESS COM-2 1 5 SPECIAL FOURTH-CLASS RATE Penalty for Private Use. S30Q BOOK