NATIONAL TRANSPORTATION SAFETY .BOARD

in the Matter of:

Investigation of Collapse of a Section of the 1-95 Bridge Case No. HY-446 Oyer the Mianus River, Greenwich, Connecticut, June 28, 1983.

EVALUATION OF FACTUAL MATERIALS AND RECOMMENDATIONS CONCERNING THE COLLAPSE OF THE MIANUS' RIVER-BRIDGE

> V 3ubir.ittea by: \ ^ / TIPPETTS-ABEETT-McCARTHY - The TAMS Building 655 Third Avenue New York, N. Y. 10 017 (212) 867-1777

Dated: December 19, 1983 Connecticut state Library

0231 00122 2624

BEFORE THE

NATIONAL TRANSPORTATION SAFETY BOARD

In the Matter of:

Investigation of Collapse of a Section of the 1-95 Bridge Case No. HY-446-83 Over the Mianus River, Greenwich, Connecticut, June 28, 1983.

EVALUATION OF FACTUAL MATERIALS AND RECOMMENDATIONS CONCERNING THE COLLAPSE OF THE MIANUS RIVER BRIDGE

Submitted by:

TIPPETTS-ABBETT-McCARTHY-STRATTON The TAMS Building 655 Third Avenue New York, N. Y. 10017 (212) 867-1777

Dated: December 19, 1983 TABLE OF CONTENTS

Page

INTRODUCTION ." 1

PART I - THE MIANUS RIVER BRIDGE WAS DESIGNED IN ACCORDANCE WITH ALL APPLICABLE DESIGN REQUIREMENTS .... 3

A. The Design For the Mianus River Bridge Was Prepared In Accordance With Specifications and Alignments Supplied By the State of Connecticut .... 5

B. The Bridge Was Designed Consistent With Engineering Theories and Techniques Prevalent In the 1950's 6

C. The Pins Used In the Pin-and-Hanger Assemblies Supporting the Bridge Were Correctly Sized, Based on Allowable Stresses That Were Correctly Selected >. 9

D. The Pin-and-Hanger Assembly and the Retaining Plate and Bolt Configuration Were Correctly Selected In Accordance With Contemporaneous Design Standards 11

E. The Collapse of the Mianus River Bridge Was Not Related to Design and Most Probably Was Caused By Gradual, Unchecked Corrosion and Forces Due to Ice Formation. 13

F. The Differences Among the Allowable Stress Used In the Pin Design, as Originally Designed, the Actual Stress In the Pin, and the Allowable Stress Which Would Be Required Using Current Design Standards, Did Not Contribute to the Mechanism of the Accident 18

i G. The Design Criticisms Offered By the State are Factually Unsupported and Should Be Disregarded 18

1. Out-of-Plane Distortions 19 2. Drainage 21 3. ConnDOT "Internal Review" (Exhibit VI-43) 23 4. S. T. Hudson Report (Exhibit VI-72) 24

PART II - WITH A MORE EFFECTIVE ORGANIZATION, THE STATE WOULD HAVE RECOGNIZED THE EXISTENCE OF PROBLEMS AND WOULD HAVE DETECTED AND HALTED THE CORROSION WHICH LED TO THE COLLAPSE OF THE MIANUS RIVER BRIDGE . 27

A. Effective Inspection Techniques Were Available to Detect the Deterioration Which Ultimately Caused the Collapse of the Mianus River Bridge 27

1. Following the collapse of the Silver Bridge in 1967, the states knew that hard-to-inspect components such as pin-and- hanger assemblies required special inspection because they were essential to a bridge's continued structural integrity 27

2. The numerous inspection manuals and guides that were developed following the collapse of the Silver Bridge highlighted the importance of detecting the problems which contributed to the collapse of the Mianus River Bridge 30

B. ConnDOT's Organizational Problems Prevented Effective Application of Available Inspection Techniques. 40

1. ConnDOT has specifically incorporated the generally applicable bridge inspection manuals into its own internal inspection requirements 40

ii 2. If ConnDOT had followed its own established procedures, it would have responded to the visible effects of corrosion 42

a. The progress and results of each of the identified mechanisms of deterioration were detectable through thorough routine inspection techniques . . . 42

b. ConnDOT's organizational structure did not facil- itate the implementation of an effective program of integrated inspection and maintenance 46

PART III - RECOMMENDATIONS 53 ^

A. Accident Investigations 53

B. Inspection and Design 53

C. Conduct of Inspections 53

D. Organization of Inspection 55

CONCLUSION 56

iii BEFORE THE

NATIONAL TRANSPORTATION SAFETY BOARD

In the Matter of:

Investigation of Collapse of Case No. HY-446-83 a Section of the 1-95 Bridge Over the Mianus River, Greenwich, Connecticut, June 28, 1983.

EVALUATION OF FACTUAL MATERIALS AND RECOMMENDATIONS CONCERNING THE COLLAPSE OF THE MIANUS RIVER BRIDGE

On June 28, 1983, at approximately 1:30 A.M., a

section of the bridge carrying Interstate Highway 1-95 over

the Mianus River in Greenwich, Connecticut, collapsed. The

National Transportation Safety Board (the "NTSB") convened

an investigation into the collapse, and the NTSB's Board of

Inquiry (the "Board") held four days of hearings on Sep-

tember 19-22, 1983. This document is filed by Tippetts-

Abbett-McCarthy-Stratton ("TAMS"), which was afforded party

status in that hearing by Order of Board Chairman Bursley dated August 16, 1983.

INTRODUCTION

TAMS is a professional architectural and engineer-

ing firm, with its principal office in New York City. TAMS now employs more than 500 people and has more than 40 years of experience in transportation, water resources, architec- ture and planning, environmental engineering and engineering management. Of particular relevance to this proceeding,

TAMS has extensive experience in the design and engineering of highways and bridges. It has designed more than 2000 bridges, and has inspected more than 1600 bridges.

This report, which reflects TAMS's expertise and experience, has been prepared to assist the Board in eval- uating the evidence gathered in its investigation and to suggest recommendations based upon that evidence. To this end, this submission is organized into three parts. The

first part addresses the original design of the Mianus River

Bridge and its consistency with all applicable design stand-

ards and Connecticut State specifications and requirements

in 1954 and 1955, as well as the role of corrosion or ice

formation as the possible cause of the collapse. This part

also demonstrates how design standards have evolved since

that time. The second part addresses the relationships between the collapse of the bridge and applicable inspection

requirements and procedures as they existed and have evolved

through the 25-year period since the bridge was constructed.

The third part presents for the Board's consideration TAMS's

recommendations based upon the foregoing discussion.

-2- PART I

THE MIANUS RIVER BRIDGE WAS DESIGNED IN ACCORDANCE WITH ALL APPLICABLE DESIGN REQUIREMENTS

Duri-ng its lifetime, any bridge is conceived, designed, constructed, and inspected and maintained. The

Board's objective in this proceeding is to identify where,

if at all, in this process a flaw occurred which allowed the

Mianus River Bridge to collapse. Based upon the evidence

gathered by the Board, this section concludes that the col-

lapse was caused by flaws in the.inspection-maintenance

stage.

The determination of causation is best made in the

framework of the conditions which existed in the 1950's.

This period witnessed the infancy of the surface transpor-

tation system which would later develop into the interstate

system. Of the 550,000 bridges in the United States now,

more than 250,000 bridges have been built since the 1950"s.

The Mianus River Bridge was designed and built between 1954

and 1958.

The technical environment has changed signifi-

cantly since that time. Communication among practicing

engineers occurred then either through technical research

-3- papers or organized meetings. Compared to the current fund- ing levels, the funds for bridges available to the Bureau of

Public Roads, predecessor to the Federal Highway Admin- istration ("FHWA"), and most States were extremely limited.

The concept of fracture-critical bridges was not a design consideration at the time the Mianus River Bridge was built. Knowledge of the effects of fatigue stresses was limited or non-existent. Redundancy was not considered an important element of design. Methods of three-dimensional analysis were not practical, and the electronic computer was not widely available for bridge design. Thus, engineers generally employed hand calculations in designing bridges.

The bridge design performed by TAMS involved more than 900 calculation sheets.

Criticisms of the design, as presented through testimony to the Board and in reports submitted to the State of Connecticut (the "State") by its consultants, ignored the fact that the bridge design standards prevailing when the bridge was designed and constructed differed significantly from current standards. Such criticisms concerned the allow- able bearing stress on the pins, the lack of redundancy in the structure, possible lateral movement of the hangers on the pins due to out-of-plane distortions, and drainage system problems. All of these issues were addressed at the hear- ings.

-4- None of the facts developed on the record point to

any inadequacies in the design under the standards prevail-

ing in 1954. The design and details used were proper and were consistent with those standards. Neither the witnesses

nor the exhibits revealed any errors in the design calcula-

tions. The drainage system selected for the bridge was com- mon to many of the bridges in Connecticut and other states.

Accordingly, the drainage problems which the Mianus River

Bridge has exhibited exist on many other bridges in Connec-

ticut.

A. The Design For the Mianus River Bridge Was Prepared In Accordance With Specifications and Alignments Supplied By the State of Connecticut.

A predecessor of TAMS, Knappen-Tippetts-Abbett-

McCarthy ("Knappen"), designed the Mianus River Bridge in

1954 and 1955 pursuant to a contract negotiated with the

State of Connecticut. (Gersten, Tr. 51, 52.) The design

was based upon criteria established at meetings with Con-

necticut officials and other engineers engaged by the State.

Specifically, other engineering firms working for the State

established the alignment for the highway then known as the

Greenwich Killingly Expressway, of which the Mianus River

Bridge is a portion. (Gersten, Tr. 54-57; Exh. VI-5a, 5b.)

The skew of the Mianus River Bridge was determined by that

mandated alignment.

-5- The actual design was prepared by Knappen, which also supervised and inspected the construction of the bridge.

The State Highway Department reviewed and approved the plans and was aware of the design details. (Gersten, Tr. 53, 54;

Gubala, Tr. 744, 745.) TAMS was also responsible for review and approval of shop drawings. The State was responsible for shop and mill inspection of steel and required materials testing. (Gersten, Tr. 65.)

No one now employed by TAMS or the State was in a responsible position in the design of the Mianus River Bridge.

The employees or partners in responsible charge of the de- sign of the bridge have left TAMS or its predecessor firms and are retired or deceased. (Gersten, Tr. 52.) Dr. Gubala, chief transportation engineer of the Department of Trans- portation of the State of Connecticut ("ConnDOT"), was un- able to identify any of the ConnDOT employees or former employees who were involved with the design and construction of the Mianus River Bridge. (Gubala, Tr. 695-96.)

B. The Bridge Was Designed Consistent With Engineering Theories and Techniques Prevalent In the 1950's.

The Mianus River Bridge is a 24-span viaduct 2656 feet long. The span that collapsed was a 100-foot two-girder span suspended from adjoining 45-foot cantilevers. The east

-6- end of the suspended span was supported by two pin-and-hanger connections; the west end rested on fixed bearings. (Gersten,

Tr. 59-60; Exh. VI-1.) The span that collapsed was one of four identical suspended spans.

The bridge design was consistent with the stand- ards accepted at the time of the execution of the design of the bridge in 1954 and 1955. These standards included the

"Standard Specifications for Highway Bridges," AASHO,* Sixth

Edition, 1953 (Exh. VI-36; Gersten, Tr. 65); and the "Stand- ard Specifications for Roads, Bridges, and Incidental Con- struction," Connecticut State Highway Department, January

1955 (Exh. VI-3). Information relating to the design was furnished to TAMS's predecessor Knappen at meetings with the

State and other consulting engineers employed to design other sections of the Expressway. (Gersten, Tr. 54, 56, 61,

62, 90, 110.)

The design executed by Knappen was typical of those of the period. (Gubala, Tr. 689.) Mr. Sears, Chief of the Review and Analysis Branch, Bridge Division, of the

FHWA, agreed that a two-girder system in the 1950's would have been an acceptable solution to spanning the channel.

AASHO, the American Association of State Highway Offi- cials, was the predecessor of AASHTO, the American Association of State Highway and Transportation Offi- cials.

-7- (Sears, Tr. 759.) Concerning the design type, Mr. Drugge acknowledged that he might have designed the Mianus River

Bridge the same way given the knowledge and conditions that existed in 1954. Indeed, Mr. Drugge pointed out that sim- ilar non-redundant designs are built today. (Drugge, Tr.

174-75.)

While the section of the Mianus River Bridge that collapsed was not redundant, this was not a design con- sideration in the 1950's. The concept of using redundant structures was not established in any of the design codes as a requirement in the 1950's, at the time the Mianus River

Bridge was designed. Indeed, redundancy is not required today. However, in the 1977 AASHTO Standard Specifications for Bridges, there is a requirement for reducing the allow- able range of stress in structures subject to repetitive loadings. The reduction of stress applies to Non-Redundant

Load Path Structures and is defined by AASHTO (p. 145) as

"[s]tructure types with a single load path where a single fracture can lead to catastrophic collapse." It is clear that current design practice does not prohibit non-redundant structures but only reduces the allowable range of s

Indeed, even Dr. Gubala acknowledged that redundancy was not required on the Mianus River Bridge when he stated "I be- lieve the designer used what was the state of the art at the time." (Gubala, Tr. 733.)

-8- C. The Pins Used In the Pin-and-Hanger Assemblies Support- ing the Bridge Were Correctly Sized, Based on Allowable Stresses That Were Correctly Selected.

The design of the pins in the pin-and-hanger as- sembly was in accordance with the provisions of the 1953

AASHO specifications. The design was based upon the proper truck loads and the correct allowable stresses, and employed the methods of calculation prevalent at the time. There was no evidence that established that the stresses or calcula- tions were improper.

The truck loading used was the H-20-S-16 truck, as provided by the AASHO specifications. (Gersten, Tr. 65-66;

Exh. VI-36 at 162.) The allowable bearing stress used for the design of the pins was 24,000 pounds per square inch

("psi"). This allowable stress was also based on AASHO standard stresses. (Gersten, Tr. 66-69; Exh. VI-36 at 177.)

Texts current at that time indicated that such an allowable stress was proper. Thus, Edward H. Gaylord, Jr., and Charles N. Gaylord, in their standard 1957 text, Design of Steel Structures, specifically referred to suspended cantilever spans as examples of pinned connections which permit only small rotations and therefore have higher allow- able bearing stresses. (Gersten, Tr. 70; Exh. VI-65 at

-9- 485-487.) Similarly, Grinter, in his Design of Modern Steel

Structures (1954), indicated that such a bearing stress was proper. (Gersten, Tr. 72-73; Exh. VI-62 at 309, 327.)

Mr. Cavanaugh, ConnDOT's Engineer of Bridges and

Structures in the Bureau of Highways, agreed that the 24,000 psi used in the design was allowed (Exh. IV-15), and Mr.

Sears of the FHWA stated that he would have approved the use of 24,000 psi at the time of the design. (Sears, Tr.

776.) The calculations showing the bearing stress value used were supplied to the State. Even the State's witness,

Mr. Drugge, acknowledged that the design stress may have been "common practice at the time" the bridge was designed.

(Drugge, Tr. 157.)

Moreover, the post-1955 development of the AASHO and AASHTO standards governing the allowable bearing stress on such pins further indicates that 24,000 psi was the cor- rect allowable stress for pins not subject to rotation when the bridge was designed. The specifications were revised only after 1964 to prescribe a lower allowable bearing stress. (Gersten, Tr. p. 73, 74, 75; Exh. VI-61, 63, 64.)

AASHO's 1964 interim specification provided for an allowable stress for pins "subject to rotation due only to expansion or deflection" of 26,000 psi. (Gersten, Tr. .73.) In 1965,

-10- this value was set at 29,000 psi for pins not subject to rotation, but was reduced to 14,000 psi for pins subject to rotation such as those in rockers and hinges. (Gersten, Tr.

75; Exh. VI-61 at 82.) Not until 1977 did AASHTO state that the value for pins "not subject to rotation . . . shall not apply to pins used in members having rotation caused by expansion or deflection." (Gersten, Tr. 75.)

This history shows a gradual clarification and evolution in detail of the AASHTO standard. A comparison of the first and last standards shows quite clearly, however, that the meaning of the term "subject to rotation" changed.

At the start, that term, as applied to allowable stresses on bearings, specifically excluded situations in which rotation was due to expansion or deflection; by 1977, it explicitly included rotation caused by expansion or deflection. Thus, regardless of what the term "subject to rotation" may mean today, those allowable bearing stresses were higher when the

Mianus River Bridge was built than they are now, and the de- sign incorporated the proper value.

D. The Pin-and-Hanger Assembly and the Retaining Plate and Bolt Configuration Were Correctly Selected In Accord- ance With Contemporaneous Design Standards.

The type of detail for the retaining plate and bolt was a common one and is shown in the American Institute

-11- of Steel Construction ("AISC") handbook. (Gersten, Tr.

86-87; Exh. VI-4.) This detail has also been used in many other bridges with suspended spans for pins of greater and

smaller diameter. (Gersten, Tr. 87.)

Bridges supported by pin-and-hanger assemblies are

not inherently unstable; such bridges exist and remain in-

tact in other states. There are numerous bridges with pin-

and-hanger assemblies in New York, New Jersey and Massachu-

setts, as well as in many other states. (Gersten, Tr. 57-58.)

These include the New Jersey Turnpike Bridge over the Passaic

River, the Roslyn Viaduct in Long Island, and several on the

Whitestone and Van Wyck Expressways in New York City. (Gersten

Tr. 62, 87, 91-92.)

The American Road and Transportation Builders

Association (ARTBA) recently surveyed all of the states

concerning suspended spans"following the collapse of the

span on the Mianus River Bridge. They received responses

from 49 states (including Connecticut) and the District of

Columbia. The responses indicate that there are probably at

least 2,000 suspended spans in the United States. An over- whelming majority of the suspended spans have tension links

and the remainder compression links. (See letter dated

October 19, 1983, from ARTBA to state highway officials

previously submitted to the Board.)

-12- Recent articles indicate that there are about 31 such bridges in New York, 68 in Connecticut, and 54 in

Massachusetts. (New Civil Engineer International, Aug.

1983.) In Michigan, there are 10 two-girder bridges and

1,132 multi-beam and girder bridges using pin-and-hanger assemblies. (Personal communication, State of Michigan

Office of the Design Engineer.) There are also analyses of such bridges in published articles and books; at least 19 of them are listed in Engineering News Record (Jan. 17, 1952;

Apr. 10, 1958; Feb. 22, 1962), Civil Engineering (May 1960;

Oct. 1962), Modern Welded Structures (Vols. I, II and IV), and other sources. Six other bridgescompleted between

1945 and 1966, received awards from the American Institute of Steel Construction. (Prize Bridges - 1945, 1954, 1957,

1959, 1963, 1966.)

E. The Collapse of the Mianus River Bridge Was Not Related to Design and Most Probably Was Caused By Gradual, Unchecked Corrosion and Forces Due to Ice Formation.

The bridge's deterioration over its 25-year life was steady and unchecked. It was agreed by all of the ex- perts who testified that this deterioration was a gradual process rather than a sudden event. Moreover, no evidence was presented which indicated that the failure was caused by the allowable bearing stresses used in the design of the

-13- pin-and-hanger assembly. Rather, the movement of the hanger off the pin was probably caused by forces related to cor- rosion and/or the formation of ice.

While one pin-and-hanger assembly collapsed, the additional assemblies and other critical portions of the bridge had suffered from varying but significant degrees of deterioration. (Drugge, Tr. 140.) Mr. Drugge specifically testified that the concavity of the plate and distress occurred "generally over the life of the bridge." (Drugge,

Tr. 145.) Similarly, observations by Mr. Wakeland, an in- vestigator with the NTSB, suggested deterioration over an extended period of time. (Wakeland, Tr. 210-211.)

Dr. O'Rourke asserted that the degradation of the bridge had probably started "three, four or five years after the bridge was constructed, and proceeded at, depending on . . . whether it was a rainy or snowy season, ... a more or less uniform rate until the time of the collapse."

(O'Rourke, Tr. 267.) Dr. O'Rourke examined and rejected the hypothesis that the bridge stress occurred as a result of a traumatic event, such as an extra heavy load, occurring after the bridge inspection and just prior to the bridge's collapse. (O'Rourke, Tr. 267.)

-14- Significantly, Dr. O'Rourke stated that in his opinion "the stress on that bridge would have been evident to an inspector for three or four years before the actual collapse." (O'Rourke, Tr. 267.) In short, as discussed below (see infra pp. 27-52), the deterioration of the bridge could have been detected and arrested at any time prior to the collapse.

Several plausible mechanisms of deterioration of the Mianus River Bridge during the past 25 years were iden- tified at the Board hearing. While the immediate causes of the collapse are unclear, all witnesses acknowledged the deterioration of the bridge's structure which clearly had occurred. The principal factors postulated as having caused this deterioration were ice and corrosion, possibly accel- erated by the presence of salt and debris.

Corrosion (i.e., rust) was certainly the most evident form of deterioration. The earliest bridge safety inspection report made available, that of the January 23,

1962, inspection, documents the rust build-up on the bridge.

(Exh. VI-10.) Moreover, in every bridge safety inspection conducted from January 24, 1975 through 1982, the State's . bridge safety inspectors reported the build-up of rust in

-15- their inspection reports. (Exh. VI-10.) The presence of rust at recent inspections was reported by both Charles

Everest and Jerry White, the bridge safety inspectors who inspected the bridge in 1982. (Everest, Tr. 538, 542-43,

560, 571; White, Tr. 591, 592-93, 609-10; Exh. IV-27, IV-28.)

Moreover, corrosion was discussed by practically all of the expert witnesses who testified at the hearing as one of the possible major causes of the collapse of the bridge. (Gersten,

Tr. 100; Drugge, Tr. 144-45, 171-72; Wakeland, Tr. 203;

O'Rourke, Tr. 252, 255, 270.) In fact, of the experts, only

Dr. Zetlin failed to postulate the causal effect of corrosion, and even he admitted the pervasive presence of corrosion on the bridge. (Zetlin, Tr. 317-18.)

The hearing witnesses also detailed the critical impact of ice in the bridge structure's deterioration. Ice can form around portions of the bridge such as the link hangers. As the ice forms, it expands and creates pressures on the structure. At the hearing, Dr. O'Rourke described the significant effect which ice had in causing the deter- ioration of the bridge's structure. In fact, while Dr.

O'Rourke believed that ice and rust acting in concert re- sulted in the degradation of the critical pin-and-hanger assembly, he stated that the pressure exerted by ice on its

-16- own would have been sufficient to push the hangers laterally off the pin. (O'Rourke, Tr. 254-55, 270; see also Gersten,

Tr. 100.)

Salt was suggested as a corrosion-accelerating agent in the structure's deterioration. (See Drugge, Tr.

163.) The salt contacted the bridge structure by two means: by reason of the bridge's close proximity to Long Island

Sound; and through the application of salt to the bridge deck by ConnDOT during the winter for snow and ice control.

This road salt was never flushed and apparently remained on the road surface or washed off the bridge, potentially con- tacting the pin-and-hanger assemblies. (LeFrancois, Exh.

IV-13 at 2; Satagaj, Tr. 432.) Joseph Pastore, a ConnDOT bridge maintenance inspector, stated that this resulted in corrosion on the bridge. (Pastore, Exh. IV-17.)

All of the aforementioned deteriorating agents occur in nature; thus, bridge inspectors must be wary of them and must inspect the bridge to ensure that they do not impair its structural integrity. In the instant situation, the corrosive nature of these forces was likely exacerbated by the drainage problems associated with the Mianus River

Bridge. These problems were brought out in detail at the hearings and included paved-over drains, scuppers filled with

-17- debris, and missing troughs. All of these problems resulted in an exces# s flow of water and salt upon the critical and sensitive elements of the bridge structure.

F. The Differences Among the Allowable Stress Used In the Pin Design, as Originally Designed, the Actual Stress In the Pin, and the Allowable Stress Which Would be Required Using Current Design Standards, Did Not Con- tribute to the Mechanism of the Accident.

The actual stresses in the pin due to design loads were substantially less than the stresses allowed by the

1953 AASHO Design Specifications. Thus, although the allow- able stress was 24,000 psi,' the actual bearing stress was only 17,900 psi. The dead load stress was 11,900 psi.

(Gersten, Tr. 68, 69; Exh. VI-36.) However, there is no in- dication that there was a bearing failure in either the pins or hangers. The mechanism of collapse was a movement of the hangers laterally off the pin. (Gersten, Tr. 99, 100, 101;

Drugge, Tr. 145, 146; O'Rourke, Tr. 230, 231, 232, 233.)

While current AASHTO specifications require a smaller bear- ing stress on pins in this type of service than AASHO re- quired in 1953, there was no failure relating to excessive bearing stress. (Gersten, Tr. 75.)

G. The Design Criticisms Offered By the State Are Fac- tually Unsupported and Should be Disregarded.

The State has offered, through a variety of wit- nesses and exhibits, several criticisms of the design of the

-18- Mianus River Bridge. These criticisms are not supported by the record evidence and should, for the reasons discussed in this section, be disregarded.

1. Out-of-Plane Distortions:

The role of out-of-plane distortions was empha- sized by Dr. Zetlin. Alone among the expert witnesses who testified, Dr. Zetlin stated his belief that the collapse was due only to out-of-plane distortions resulting in lat- eral forces on the hanger. These forces were postulated to have pushed the hanger off the pin over a period of 15 to 20 years. (Zetlin, Tr. 280, 328.)* Dr. Zetlin also stated that the "collapse had occurred at the northeast corner"

(Zetlin, Tr. 307), not the southeast corner as others had testified. Dr. Zetlin's theories remain speculative and are computationally unsupported. His theory that the failure occurred at the northeast corner is contradicted by the physical evidence.

Dr. Zetlin made no calculations to establish the magnitude of the out-of-plane distortions causing lateral

However, Dr. Zetlin agreed with the other witnesses that rust had acted as a corrosive force on the bridge (Zetlin, Tr. 318), and that whatever the cause of the collapse was, it occurred over a long period of time (Zetlin, Tr. 298, 328).

-19- forces, if in fact these forces existed. At the hearing,

Dr. Zetlin referred to little more than preliminary cal-

culations and "sheets of yellow paper," neither of which has been produced. He stated that such calculations were dif-

ferent from the type of calculations usually done for pre-

liminary design. No numbers were available. (Zetlin, 305,

326, 331-332.) Since the hearing Dr. Zetlin has produced

several "Progress Reports" but no usable calculations. Dir.

O'Rourke, in his testimony, could not justify the hypothesis

that out-of-plane movements caused the collapse of the span.

(O'Rourke, Tr. 258-261.)

Moreover, no evidence has been presented to sub-

stantiate Dr. Zetlin's observations that out-of-plane dis-

tortions due to the skew of the bridge caused movements

along the pin. Out-of-plane distortions occur in square

bridges as well as skew bridges and the rotations of the

floorbeams are comparable in value. (Gersten, Tr. 98;

O'Rourke, Tr. 258-261.)

Dr. Zetlin's belief that the collapse occurred at

the northeast corner is contrary to the testimony of others

and is not consistent with the physical evidence. The di-

rection of the bent fingers in the expansion joint is in-

consistent with the northeast corner's collapsing first.

-20- (Wakeland, Tr. 208-10; O'Rourke, Tr. 245-46.) The fascia girder, which supported the outside of the span, had the most damage, whereas the median girder was relatively un- damaged. This indicates that the fascia girder impacted the water and the river bottom first, which would have occurred if the southeast corner had collapsed first. The southwest fixed bearing was pulled off. (Zetlin, Tr. 333.) This also indicates that the southeast corner collapsed first.

In short, Dr. Zetlin's theories are unsupported by observed facts, as yet unconfirmed by the metallurgical tests he requires and expects to rely on, or verified by any viable calculations. Indeed, Dr. Zetlin's theories are inconsistent with the physical evidence. Even if the cal^ culations he proposes are possible today (which remains to be seen), they could not feasibly have been made in 1954 and 1955. Therefore, Dr. Zetlin's theories at their current stage of articulation do not point to any deficiencies in the design of the Mianus River Bridge or explain why it collapsed.

2. Drainage:

Dr. Gubala stated that the drainage system was

"designed not to take the water that would flow down the

-21- gutterline totally, but to bypass much of it." The slope of the drainage system was also criticized. (Gubala, Tr. 691.)

The implication of these remarks was that the drainage was designed incorrectly and that the scuppers should have picked up all of the water.

In fact, the drainage system was properly de- signed. It consisted of two basic components: scuppers located along the curbs and copper troughs under the finger joints. The purpose of the troughs was to catch any water passing the roadway scuppers and to prevent that water from dropping onto the pins and hangers. The trough on the span that collapsed sloped from the southeast corner to the north- east corner at a slope of 1.05 percent. Water would, there- fore, be conducted to the downspout at the median and dis- charged into the river.

f

Referring specifically to Dr. Gubala's criticisms, it is not normal to design scuppers to pick up all water.

Scuppers are properly designed to limit the spread of water on the roadway to a certain portion of the width of the through-traffic lane. It is rarely practical to design gutter sections to contain all of the run-off, even from frequent rains. The design frequency and the inlet spacing are selected so as to keep the spread of water on the trav-

-22- elled way within tolerable limits. (See "Drainage of High- way Pavements," Hydraulic Engineering Circular No. 12, dated

March 1969, prepared by the Hydraulics Branch, Bridge Divi- sion, of the U.S. Bureau of Public Roads.) This reference covers standard practice of drainage design and presents basic criteria to follow during design.

In sum, the design of the drainage system is un- related to structural design and consequently bears no causal relationship to the collapse of the bridge. The record demonstrates quite clearly that the drainage problems ex- perienced were due to two causes: the failure to maintain the drainage system and the paving-over of drains. In this respect, the Mianus River Bridge was not different than other bridges in Connecticut alluded to on the record.

(Supina, Tr. 453.)

3. ConnDOT "Internal Review" (Exhibit VI-43):

ConnDOT's "Internal Review" (Exh. VI-43) does not contribute to an orderly evaluation of the bridge's design or the causes of its collapse. However, since the report is an exhibit, it is appropriate to highlight its inaccuracy on these points. On pages 44 and 45 statements are made that torsional forces and lateral forces due to the extreme skew of the bridge "apparently were the main cause of the hanger

-23- slipping off the pin." These statements constitute a mis-

characterization of the testimony of Dr. Zetlin and Mr.

Drugge. No evidence was presented at the Hearing to justify

this conclusion. There were no calculations presented to document this, and no metallurgical tests have been pre-

sented to identify the mode of failure.

4. S. T. Hudson Report (Exhibit VI-72):

Finally, nothing in the report apparently prepared

by a firm known as S. T. Hudson, International (Exh. VI-72),

contributes to an assessment of the bridge's design or col-

lapse. The nature of the report is unexplained. The ex-

hibit appears to be an excerpt from a larger report or

series of reports, since it starts on page 1 with Item 4 and

relates to the probable cause of failure. The rest of the

report is apparently missing. The purpose of the report is

nowhere explained. The qualifications of the authors are

not given. It is not clear whether the shortcomings which

are discussed concern engineering practice in 1983 or the

1950's.

These uncertainties would have been cleared up if

it had been possible to cross-examine the authors of Exhibit

VI-72. The specific comments on this exhibit will relate to

engineering practice when the bridge was designed in the

1950's.

-24- The statements regarding lack of redundancy are inaccurate. Bridges of similar design do not usually pro- vide three or four girders. Non-redundant two girder bridges were and are common. (See O'Rourke, Tr. 251.) Many long span bridges over waterways use either two girders, two trusses, two suspension cables, or two arches, and as such are non-redundant. Most single-track railroad bridges use two girders or trusses and also are non-redundant. Most pedestrian bridges use either two girders or two beams.

There are a number of two-girder bridges using pin assem- blies in addition to the Mianus River Bridge. Included are the Roslyn Viaduct in Long Island, the New Jersey Turnpike

Bridge over the Passaic River, the Calcasieu River Bridge carrying 1-210 in Louisiana, the Whiskey Creek Bridge in

California, and the Trinity River Bridge in Hoopa, California

The statement that "[t]here was no built in safety factor" (Exh. VI-72 at 1) is without foundation. The factor of safety used in the design of the Mianus River Bridge components was the same as that used in all bridge com- ponents. The design used the proper allowable stresses and therefore had the built-in safety factor required by the

AASHO code.

-25- Contrary to the statement that there was a rel- ative lack of protection against corrosion (Exh. VI-72 at

1), no evidence was presented that engineers used stainless steel on pin-and-hanger assemblies designed in the 1950's.

In addition, AASHO specifications clearly allowed a variety of steels to be used for pins in bridges, all related to the strength of the material selected, not to its corrosion resistance. Similarly, the pin selected for the Mianus

River Bridge met AASHO specifications and was comparable with the pins used for other bridges having similar details.

-26- PART II

WITH A MORE EFFECTIVE ORGANIZATION, THE STATE WOULD HAVE RECOGNIZED THE EXISTENCE OF PROBLEMS AND WOULD HAVE DETECTED AND HALTED THE CORROSION WHICH LED TO THE COLLAPSE OF THE MIANUS RIVER BRIDGE

The collapse of the Mianus River Bridge occurred within the context of a national concern over bridge safety.

Nine years after the Mianus River Bridge was completed, the

Silver Bridge over the Ohio River at Point Pleasant, West

Virginia, collapsed. The disaster had two effects which are relevant to this proceeding. First, as described by the

NTSB in its report on the collapse, the component of the

Silver Bridge which failed was similar to the pin-and-hanger assembly on the Mianus River Bridge. Second, the collapse stimulated the evolution and development of today's inten- sive bridge inspection programs and legal requirements.

A. Effective Inspection Techniques Were Available to Detect the Deterioration Which Ultimately Caused the Collapse of the Mianus River Bridge.

1. Following the collapse of the Silver Bridge in 1967, the states knew that hard-to-inspect com- ponents such as pin-and-hanger assemblies required special inspection because they were essential to a bridge's continued structural integrity.

On December 15, 1967, the Silver Bridge across the

Ohio River at Point Pleasant, West Virginia, collapsed,

-27- killing 46 people. This disaster and the governmental re- sponse to it put every state on notice of the critical im- portance of bridge inspections. More specifically, the

State was put on notice of the importance of inspecting such critical but hard-to-inspect assemblies as the pin-and- hanger bearings on the Mianus River Bridge.

The NTSB investigated the collapse and issued two reports exploring in detail the causes of that collapse.

NTSB, Collapse of U.S. 35 Highway Bridge, Point Pleasant,

West Virginia, December 15> 1967, Case No. SS-H-2 (October

4, 1968 ("Interim Report") and December 16, 1970 ("Final Re- port")). The NTSB determined that the collapse was caused by the failure of a difficult-to-inspect eyebar in the eye- bar chain which supported the suspension span. The NTSB identified seven design trends, "each of which was common in engineering practice in the era in which [the Silver Bridge] was designed," which contributed to the failure. (Final

Report at 122.) The report, which was distributed to the states, highlighted the importance of inspecting bridges which reflected similar design trends.

The Mianus River Bridge was similar in several respects (see Final Report at 122-23), not the least of which was the similarity between the pin-and-hanger detail

-28- on the Mianus River Bridge and the eyebar joint on the Silver

Bridge. Thus, from the NTSB's reports alone, Connecticut had reason to be cognizant of the need to subject the pin- and-hanger assemblies to searching scrutiny.

However, the NTSB's reports did not exist in a vacuum. There were, in fact, related events which should have further heightened Connecticut's sensitivity to the need to inspect the Mianus River Bridge. On March 12, 1968, the FHWA distributed to the states "An Informational Guide for Inspection of Highway Bridges," which had been prepared

in cooperation with AASHO.* This Guide, which predated the legal requirements which now apply to bridge inspections, opened with a reference to the Silver Bridge collapse, and stated:

It is advisable that all official public agencies that construct, operate and maintain highway facilities take special action now to again reevaluate the capability of bridges and related facilities to continue to accom- modate highway traffic and to take other precautionary measures to reassure that other such facilities will not fail under active service.

This Guide was also marked as Exhibit 3U in the NTSB's investigation of the Silver Bridge collapse. Since it was. also distributed to the States, it is reasonable for the Board now to take administrative notice of it.

-29- Each state was "expected to make further review of the ade- quacy of the bridges" under its jurisdiction. A priority

list spelling out the order for conducting inspections

listed as the second priority " [structures whose ability to

function properly depends on the ability of the pins or

joints to rotate and translate properly." The seventh pri-

ority was for "[structures or routes where deicing chem-

icals are used liberally." Special attention during in-

spections was directed to bearings and expansion joints.

Thus, as early as 1968, the States had clear no-

tice of the importance of inspecting pin-and-hanger assem-

blies such as those found on the Mianus River Bridge. In

the specific case of the Mianus River Bridge, Connecticut

should also have recognized that the bridge had several

features which made it essential that the bridge receive

careful inspection. Moreover, by that time, the bridge had

been inspected at least five times. (See Exh. VI-10.) The

inspection reports consistently indicated that drains were

not being cleaned, which should have further alerted the

State to inspect the bridge carefully.

2. The numerous inspection manuals and guides that were developed following the collapse of the Silver Bridge highlighted the importance of detecting the problems which contributed to the collapse of the Mianus River Bridge.

The collapse in 1967 of the Silver Bridge over the

Ohio River at Point Pleasant, West Virginia, focused atten-

-30- tion on the necessity for regular programs of bridge safety inspection. In response to the collapse, and partly as a . result of the two reports on the collapse prepared by the

NTSB, the federal government began to promulgate regulations prescribing minimum budget safety inspection requirements.

At the same time, AASHO, which had published a highway in- spection manual in 1964,* prior to the Silver Bridge col- lapse, continued to revise and reissue its bridge safety inspection and related manuals to include new information.

Although these early manuals have now been sup- plemented by later editions, the evolution of the manuals illustrates the range, quality, and detail of information that was made available to the states as long ago as 1964, and which was available for their use in developing bridge inspection programs. The steady growth in the number and complexity of these manuals reflects a learning process.

Each subsequent manual built upon its predecessors; those earlier editions were not retracted, and their instructions were not to be discarded. Rather, the amount of information which was available to organizations such as ConnDOT grew steadily over time.

Indeed, this manual, entitled "Guide for Maintenance Inspections," was included as Exhibit 3M in the record of the NTSB's investigation of the Silver Bridge col- lapse.

-31- Thus, the 1964 AASHO Guide for Maintenance Inspec- tions stated unequivocally (at p. 27) that bridge inspec- tions must be thorough: "Inspections should be complete in essential detail and in no case should difficulty of access to any part or any member be permitted to interfere with thorough inspection." This did not change with time. No subsequent manual retracted this instruction. Thus, as early as 1964, Connecticut was on notice that all parts of its bridges were to be inspected regardless of ease of ac- cess. The importance of this warning was underscored by the

NTSB's two highly detailed reports on the collapse of the

Silver Bridge and their findings regarding the inspectabil- ity of the components whose failure precipitated the col- lapse.

The proper conduct of bridge safety inspections is described in manuals and guides that are readily available from the FHWA or AASHTO. (Kjellson, Tr. 511.) Federal regulations require the state to comply with these manuals, in particular the Training Manual and the AASHTO Manual

(Exhs. VI-15, VI-20), in carrying out their bridge safety inspections. (Ahlskog, Tr. 799-800, 811, 816-18; Exh. VI-31.

The manuals clearly emphasize the importance of inspecting pin-and-hanger assemblies on cantilever bridges, as well as

-32- the related expansion joints and drainage systems. (Exh.

VI-15 at 5-62, 5-71 to 5-73, 5-80 to 5-81; Exh. VI-20 at

8-9.) None of the recommended inspections are described as

being intended to ferret out a single mechanism of failure.

Rather, they are intended to identify any form of distress

in these critical assemblies.

In addition, as discussed in this section, the

bridge inspection manuals and training guides provide un-

ambiguous directions to inspect pin-and-hanger assemblies.

These directions were specifically aimed at the type of

pin-and-hanger assemblies found on the Mianus River Bridge.

The directions did not limit the required inspection to any

specific potential bridge failure mechanism. Rather, any of

the potential mechanisms of failure identified in this pro-

ceeding were to be scrutinized in a properly conducted in-

spection carried out pursuant to these manuals.

Four generally applicable bridge safety inspection

guides and manuals were identified on the record in this

proceeding. These were:

i) Exhibit VI-15: "Bridge Inspector's Training Manual 70," published in 1970 and revised in 1979 by the Federal Highway Administration of the U. S. Department of Transporta- tion (referred to as the "Training Manual");

-33- ii) Exhibit VI-17: "Bridge Inspector Training Course: Inspection Check- lists" . iii) Exhibit VI-18: "AASHTO Manual for Bridge Maintenance - 1976," pub- lished by AASHTO in 1976.

iv) Exhibit VI-20: "Manual for Main- tenance Inspection of Bridges," revised in 1982 by AASHTO (referred to as the "AASHTO Manual").

The inspection manuals articulate a series of pro- cedures that would have enabled Connecticut to identify potential failure mechanisms before they could have caused a collapse. Some of these requirements are general in nature; others apply directly to specific aspects of the Mianus

River Bridge.

The principal reference is the Bridge Inspector's

Training Manual. (Exh. VI-15.) As supplemented by the

Inspection Checklists (Exh. VI-17), the Training Manual is the basic teaching resource for bridge inspectors in Con- necticut as well as the federal government. (Thomas, Tr.

624-25; Cavanaugh, Tr. 655-56; Ahlskog, Tr. 801-02.) It is lavishly illustrated and highly detailed. All Connecticut bridge safety inspectors had taken the ConnDOT Bridge Safety

Inspections Division's training course at least once. (Cav- anaugh, Tr. 656.) All were familiar with the Training Man- ual. (Everest, Tr. 543; White, Tr. 586.) Indeed, they used

-34- it as a reference resource and kept it in their truck.

(Everest, Tr. 544.)

The general provisions of the Training Manual relate to the planning and thoroughness of the inspec- tion. In planning an inspection, the inspector is directed to review all available materials, including plans and pre- vious inspection reports. (Exh. VI-15 at 3-2.) Such a review would have identified the critical members of the

Mianus River Bridge and would have alerted the inspector to previously identified problem areas. The Manual stated that the inspection should be thorough, with particular attention focused on "[s]tructurally important members" and "[m]embers most susceptible to deterioration or damage." (Exh. VI-15 at 4-1.) If this step had been coordinated with a review of plans and prior inspection reports, attention would have been directed to the pin-and-hanger assemblies.

In addition, the Training Manual clearly states that dirt and debris must be removed if necessary "to permit precise measurement:"

Pre-inspection Cleaning. It will often be necessary to remove dust, -debris, rust, paint scale, or animal wastes before inspecting a bridge member. Scrapers, wire brushes, air jets, or shot blasting are very useful for this purpose. A clean surface is partic- ularly important when electronic devices are used for inspection of steel or concrete.

-35- (Exh. VI-15 at 4-4.) Visual inspection must be supplemented with special techniques where necessary. (Exh. VI-15 at

4-1.) At the least, these requirements indicate that the

Mianus River Bridge should have been cleaned if the presence of debris or pigeon droppings impeded inspection, which, indeed, it did.* (Exh. VI-43 at 58.)

The Training Manual identifies eleven factors which can cause deterioration of steel members. Among these are air and moisture, "especially in a marine climate," de- icing agents, and animal wastes. (Exh. VI—15 at 5—8.) Given the location of the Mianus River Bridge close to Long Island

Sound, the long-term use of deicers on the bridge (Satagaj,

Tr. 436), and the acknowledged presence of animal wastes on the bridge (Exh. VI-43 at 58), each of these factors should have been especially important to an inspector examining the

Mianus River Bridge.

With regard to specific aspects of the bridge structure, inspectors of main supporting members are di- rected to be "particularly thorough" because "their failure could cause the collapse of the bridge." (Exh. VI-15 at

In fact, however, the State had not had' a blaster for cleaning such components for at least ten years. (Exh. IV-16.)

-36- 4-2.) Among the members specified for such inspection are main girders and hangers. The inspector is directed to look for corrosion, connection slippage, and deformation due to overload. (Exh. VI-15 at 4-4.)

Particular attention is directed repeatedly to pin-and-hanger assemblies that are critical to the support of the bridge:

Where the main load of the bridge is carried by a single member or element whose failure would result in the collapse of the struc- ture, the member should be inspected very thoroughly for cracks and flaws either by visual inspection or by a non-destructive technique, such as ultrasonics or radio- graphy. The pins and the hangers on the suspended span of a two-girder cantilever bridge, or the pins in a pin-connected truss, are typical examples of such members.

(Exh. VI-15 at 4-4 (emphasis added).) The inspector is

specifically directed to examine cantilever pin-and-hanger expansion devices (Exh. VI-15 at 5-41, 5-62) to ensure that

they are functioning properly, that they are free of cor-

rosion and debris (Exh. VI-15 at 5-60), and that rust accum-

ulation has not impaired the function of the assem- bly (Exh. VI-15 at 5-43). In addition, the inspector is directed to inspect areas "that may be exposed to roadway drainage," and

[a]t any point where two plates are in face to face contact and water can enter (such as between a cover plate and a flange). If

-37- rusting occurs at this interface, the ex- pansive force created will be great enough to spread the plates.

(Exh. VI-15 at 5-42.) The pin-and-hanger assemblies on the

Mianus River Bridge were exposed to roadway drainage and included several such face-to-face plates; a pre-inspection review of the bridge's plans would have revealed this ex- posure.

The Training Manual focuses attention on expansion joints and drainage. The inspector is directed to check clearances within the joints and to see that joints and drains are free of debris. (Exh. VI-15 at 5-72, 5-81.) In addition, the bottom of the joint must be inspected "re- gardless of accessibility." (Exh. VI-15 at 5-73.) Drainage at the expansion joint requires similar attention:

The gutters under expansion dams fill up very rapidly, especially where roads are heavily sanded in winter. This causes the storm water to over- flow onto the bearings, end diaphragms, pier caps, and bridge seats, resulting in severe rusting of the steel and deterioration of the concrete. Of special consequence is the deterioration and freezing of expansion bearings and rollers.

(Exh. VI-15 at 5-81.)

The AASHTO Manual for Bridge Maintenance contained a pointed discussion of the problems associated with pin-

-38- and-hanger assemblies.* This should have served as a "red

flag," alerting the supervisory personnel to the need to direct the bridge safety inspectors to scrutinize the pin-

and-hanger assemblies:

Pin-and-Hanger Bearings:...

1. Problem

Rusting between the plates is very dif- ficult to detect unless bearing is dis- mantled.

2. Prevention

Prevention is impossible since we cannot paint between plates. Proper design is the only solution.

If joints get clogged, it in fact fixes the span. The joints must be kept cleaned if failure is to be prevented.

(Exh. VI-18 at 182.) This discussion should have alerted

the supervisor to the need for constant vigilance at all

pin-and-hanger assemblies. Moreover, it should be noted

that this manual was published in 1976; Connecticut received

this warning seven years before the collapse of the Mianus

River Bridge.

Although the AASHTO Maintenance Manual is directed primarily to describing the maintenance procedures normally used to correct frequently encountered prob- lems of bridge repair, its discussion of these problems provides an additional source of information to the engineers responsible for bridge safety inspections. Thus, its extensive discussion of problems associated with drainage, expansion joints, and bearing systems (Exh. VI-18 at 63-66, 89-95, 171-182) should have alerted a supervisor to the need to inspect these areas with particular care.

-39- B. ConnDOT's Organizational Problems Prevented Effective Application of Available Inspection Techniques.

The record in this proceeding contains numerous internal documents prepared by the State of Connecticut and relating to bridge inspections. Like the manuals discussed in the previous section, these documents establish inspec- tion procedures that would have directed attention to the pin-and-hanger assemblies on the Mianus River Bridge and enabled the State to detect and arrest their deterioration before it led to the bridge's collapse.

1. ConnDOT had prepared guides for its own internal inspection requirements which specifically in- corporated the generally applicable bridge in- spection manuals.

Of the inspection manuals introduced as exhibits, the principal manuals are Exhibits VI-15 and VI-20. Al- though neither volume was promulgated by the State of Con- necticut, both are applicable to it. Federal regulations require all states to comply with the Training Manual and the AASHTO Manual. (Ahlskog, Tr. 799-800, 810-11, 816-18,

820, 825; Exh. VI-31.) In addition, the State's own in- ternal memoranda (Exh. VI-12a) incorporate the following materials into the State's "Procedural Manual":

By reference, the following publications are made a part of this Manual:

-40- National Bridge Inspection Standards

Manual for Maintenance Inspection of Bridges, AASHTO - 1974

Bridge Inspectors Training Manual 70 - Federal Highway Administration

Recording & Coding Guide for the Struc- ture Inventory and Appraisal of the Nation's Bridges - July 1972

In addition, ConnDOT inspectors had taken the federal bridge inspector's training course and could therefore have been expected to be familiar at least with the Training Manual.

(Thomas, Tr. 624-26; Cavanaugh, Tr. 657, 662, 676.) Fur- ther, the State's Field Inspection Booklet (Exh. VI-16) reprints several provisions of the Training Manual and the

AASHTO Manual. (Exh. VI-16.) The State's "Internal Review"

(Exh. VI-43) acknowledges that the federal standards apply.

(Exh. VI-43 at 18.) The Board should note, finally, that one of ConnDOT's bridge inspectors acknowledged that non- federal aid bridges are subject to the same inspection standards and procedures as federal aid bridges. (Everest,

Tr. 557.)

The Inspection Booklet summarizes the requirements spelled out in greater detail in the Training Manual and the

AASHTO Manual. It specifically directs the inspector's attention to i) "cantilever hanger-and-pin connections,"

-41- ii) areas under joints and "at any other points that may be exposed to roadway drainage," and iii) face-to-face plates.

(Exh. VI-16 at 8.) Cleanliness, "especially on the top side of the bottom flange," must be checked (Exh. VI-16 at 8), as must the functioning of hangers on cantilevered bridges

(Exh. VI-16 at 10).

Finally, several internal memoranda prepared by

ConnDOT officials were circulated to call attention to spe- cific aspects of state bridge safety inspections. These memoranda were sent to all bridge safety inspectors, and dealt with the importance of inspecting bridge bearings and joints (Exh. VI-12c, 12f); proper use of the snooper (Exh.

VI-12e); and the need ±o inspect skewed bridges because of the possible effects of out-of-plane movements (Exh. VI-12d).

2. If ConnDOT had followed its own established pro- cedures, it could have responded to the visible effects of corrosion.

a. The progress and results of each of the iden- tified mechanisms of deterioration were de- tectable through thorough routine inspection techniques.

Various witnesses testified that the effects of deterioration were in fact visible. Several expert wit- nesses testified about their inspection of the Mianus River

Bridge after the collapse. Their testimony demonstrates

-42- that several indications of deterioration or distress should have been readily apparent to a properly trained and equipped inspector. In addition, the testimony and actions of these experts also indicate that visual inspections alone were inadequate and that application of more specialized in- spection techniques immediately revealed the degree of . deterioration on the remaining spans.

On the day after the collapse, runoff was observed to be falling through the expansion joints instead of the drains and was observed to have left dark stains on the beams below. (Wakeland, Tr. 203.) The other intact spans were, to varying degrees, measurably lower than the adjacent spans. (Wakeland, Tr 206, 212.) The finger joints of the expansion joint of the fallen span were observed to have been in contact. (Wakeland, Tr. 208.) These conditions were readily apparent, and should have been evident to a safety inspector as signs of a potential problem. (Wake- land, Tr. 210, 215; Drugge, Tr. 148.) More importantly, it is extremely unlikely that they were present when the Mianus

River Bridge was built. (Wakeland, Tr. 216.)

Deterioration of the pin-and-hanger assemblies was also clearly visible. Rusting or freezing of the assemblies was noted five times in the inspection reports from 1975 to

-43- 1982. (Exh. VI-10.) According to Dr. Zetlin, "it was easy to observe corrosion." (Zetlin, Tr. 318.) Rust would have been clearly visible from the snooper, or even through bi- noculars from the ground. (Drugge, Tr. 179, 183.) The presence of rust "certainly" would have caused the inspector to go out and look at the pin-and-hanger assembly in detail.

(Drugge, Tr. 156.) At the least, he would have notified his superiors "that perhaps the condition was serious and needed further investigation." (Drugge, Tr. 156.) The deformation

("dishing") of the retainer plate was clearly visible from

"more than six feet away." (O'Rourke, Tr. 237.) It was visible from the snooper.* (Drugge, Tr. 145.) The distance between the girder webs and the hanger of the fallen span was measured and shown to be twice the distance indicated on the plans. (O'Rourke, Tr. 241, 255.) This distance would have been "easily" measurable (O'Rourke, Tr. 251; Drugge,

Tr. 141, 153), which would permit anyone with access to the plans to determine the amount of bearing surface. (Drugge,

Significantly, ConnDOT, in its "Internal Review" ac- knowledges that the outer pin and hanger assembly would have been fully inspectable if the snooper had in fact been used. Both outer pins and the lower inside pin were inspectable from the snooper (Exh. VI-43 at 39, 42). The upper inside pin was inspectable at close range from the floorbeams (Exh. VI-43 at 42), as it in fact was during the September 1982 inspection.

-44- Tr. 141.) In short, "the stress on the bridge would have been evident to an inspector for three or four years before the actual collapse." (O'Rourke, Tr. 267.)

These readily visible conditions strongly indi- cated a need to pursue more detailed examinations, as sug- gested by the Training Manual. (Exh. VI-15 at 4-1.) Such steps, which included drilling through and then removing the retainer plates, immediately indicated the nature and ad- vanced degree of the deterioration which had occurred.

(Drugge, Tr. 141, 146.)

Moreover, even if the State had not been inspect- ing the Mianus River Bridge regularly, it was certainly on notice that there were significant problems associated with the Bridge. As developed in an independent investigation conducted by the Connecticut State Police, the record is re- plete with evidence of public complaints or inquiries about noises and structural problems. See "An Investigation into the State Department of Transportation's Processing of Com- plaints Concerning the Mianus River Bridge," Conn. State

Police Case No. G83-259200 (the "Police Report"). Moreover, the report prepared by the Connecticut State Police doc- uments numerous other complaints which were lodged with

ConnDOT.

-45- As described in the Police Report, the volume and

frequency of complaints from the disinterested public, is

significant for two reasons. First, the fact that the pub-

lic could perceive problems highlights the degree to which

those problems should have been apparent to the State's

trained observers. Second, it was incumbent upon the State

to act decisively to determine the basis for the persistence of these complaints.

b. ConnDOT's organizational structure did not facilitate the implementation of an effective program of integrated inspection and main- tenance.

ConnDOT seemingly was not organized in a manner which facilitated making proper observations or transmitting

reports to persons who would understand their seriousness.

Many of these problems were detailed in the State's own

report on the bridge collapse. Others were detailed at

length in the testimony.

Inspection of the bridge was split between two en-

tirely distinct and separate units: the bridge safety in-

spection unit and the bridge maintenance inspection unit.

(Supina, Tr. 447-48.) Various persons actually involved in

the hands-on work of these units suggested that this organ-

izational structure was not productive. (LeFrancois, Exh.

-46- IV-13; Thomas, Exh. IV-14.) In fact, Mr. LeFrancois asserted

that'combining the two units would improve and expedite the maintenance of critical systems. (LeFrancois, Exh. IV-13.)

Aside from this, however, it appears that there was very

little coordination and communication between the two de- partments. (Thomas, Tr. 632, 650-51; Cavanaugh, Tr. 661;

Gubala, Tr. 734-35.) As the State's "Internal Review" ac- knowledged, the bridge safety and bridge maintenance in-

spectors exchange neither inspection reports nor inspection

schedules. (Exh. VI-43 at 15.) Clearly, while bridge main-

tenance inspectors were not trained in bridge safety inspec-

tion (they had little training other than on-the-job training

from co-workers with presumably no formal training; Supina,

Tr. 446), the observations contained in their reports might

have indicated to others who were better trained that the bridge had serious structural problems (see Supina, Tr.

450). For example, various maintenance inspectors testified

that they knew about the clogged drains, paved-over scuppers

and corrosion well prior to the bridge collapse. (Hemingway,

Tr. 363; LeBlanc, Tr. 374; Hemingway, Exh. IV-12; LeFrancois,

Exh. IV-13; LeBlanc, Exh. IV-16.) However, the bridge safety

inspectors never saw these reports; and as Dr. Gubala pointed

out, they were never reviewed by a professional engineer

(Gubala, Exh. IV-19).

-47- On the other hand, the bridge safety inspectors did not even seem to consider requesting maintenance, pre- ventive or otherwise, to maintain the integrity of the bridge's structure. All requests for maintenance from bridge safety inspectors were supposed to be transmitted from Mr. Cavanaugh's office to Mr. Supina's office. (Supina,

Tr. 448-449, 457-460, 466-467.) Nevertheless, despite the admitted problems with some of Connecticut's bridges, Mr.

Supina never saw the bridge safety inspector's reports and received only five to ten requests for maintenance each year from Mr. Cavanaugh. (Supina, Tr. 457; Supina, Exh. IV-18.)

There were other apparent communication problems within the two individual sections. For example, Mr. Crucitti stated that he was involved in the paving-over of the scup- pers in the early to mid-1970's. He assumed that these scuppers were being covered to protect them while certain contracting work was being performed. He believed that the scuppers would be uncovered once the contracting work was over. (Crucitti, Tr. 390-392, 406.) In fact, these scuppers were not uncovered, despite the fact that this condition was consistently listed on the inspection or maintenance re- ports. Finally, in March 1983, Mr. LeFrancois advised his superior, Mr. Smith, of the situation. (LeFrancois, Tr.

-48- 410-411, 432.) Somewhere along the line, however, the line of communication was broken because Mr. Satagaj, Mr. Smith's superior, stated that he did not know about this condition until the bridge collapsed. (Satagaj, Tr. 426.) Mr. Supina stated that he would never pave over a drain (Supina, Tr.

452-453; see Supina, Tr. 467-468); however, Mr. LeFrancois, who stated he had authority to uncover the drains (LeFrancois,

Tr. 422), did not do so because he was waiting for orders from his superiors (LeFrancois, Tr. 410-411).

There also were communication problems involving the bridge safety inspectors. Mr. White testified that on four or five occasions he advised his superiors about the dangerous conditions on the Mianus River Bridge, but there is no evidence of any changes having been effected. (White,

Tr. 591.) Similarly, none of Mr. White's superiors ever noted or acted upon the fact that the report of the Sep- tember 1982 inspection contained no field notes. (White,

Tr. 615-616.)

Additionally, problems may have occurred because both the bridge safety and bridge maintenance inspectors had little formal training and had not read many of the AASHTO materials. Mr. Everest stated that they never took measure- ments, never requested the bridge plans prior to the in- spections (Everest, Exh. IV-27), and had never been in- structed on how to inspect pin-and-hanger assemblies.

Another state agency, the Connecticut State Police

Department, has also investigated the incident; its report discusses another coordination difficulty within the ConnDOT system. Dr. Gubala described in his interview ConnDOT's system for handling and processing complaints. (Gubala,

Exh. IV-19.) Unfortunately, the State Police determined that this system did not function properly as regards the

Mianus River Bridge. Most complaints were made to ConnDOT by telephone; yet the State Police concluded that at least six confirmed phone calls, and perhaps many more, in which complaints were registered as to conditions on the Mianus

River Bridge, were lost as a result of ConnDOT's "informal process" of handling complaints. Additionally, ConnDOT

District #3 violated its own procedures and had no records of any complaints. Moreover, more complaints might have been called into ConnDOT except that the "complaint phone" at the Greenwich ConnDOT garage was often unmanned. (Police

Report, p. A34.)

Most critically, none of the management personnel, bridge maintainers, or bridge inspectors had any knowledge of the complaints filed other than the ones with which they

-50- were personally involved. Of the 17 callers to the ConnDOT who said they had reached a clerk and were able to file a complaint, 10 complained about noise and vibration problems on the bridge. (Police Report, p. A34.)

Had ConnDOT engineers been aware of this high volume of complaints, perhaps they would have known that there was a serious structural problem on the Mianus River

Bridge, particularly in light of the graphic nature of the complaints made to ConnDOT (see, e.g., Police Report, pp.

B13, B33). The State Police report also detailed the con- fusion and lack of a coherent state policy regarding over- weight vehicles on the bridge. (Police Report, p. A33.)

ConnDOT"s inspection efforts were greatly hampered by a lack of funding. This funding limitation would have rendered proper inspection difficult with the best of organ- izations. Perhaps the strongest evidence of this situation was that ConnDOT's only snooper was out of service as of

August 1982 and thus was not available for use in the Sep- tember 1982 safety inspection of the Mianus River Bridge.

(Exhs. IV-12, IV-14.) This was particularly critical, as the Mianus River Bridge was one of 162 bridges in Connec- ticut for which a snooper was required for proper inspec-

-51- tion. (Exh. VI-43 at 48.) Specifically, the snooper was needed to inspect many of the pin-and-hanger assemblies on this bridge. Originally, ConnDOT was scheduled to have four snoopers but due to funding problems had only one, and that had been removed from service.

Furthermore, the tools and equipment available to maintenance and safety inspectors were inadequate and had been dwindling over the years. These included limited equip- ment for critical maintenance and inspection (e.g., scaf- folding and usable catwalks). (LeBlanc, Tr. 378, 380, 384,

386; Crucitti, Tr. 398, 405; Exhs. IV-16, IV-26.) Moreover, when the State did recognize that repairs were needed, they were often delayed due to funding problems. (See, e.g.,

Police Report, p. B39.)

-52- PART III

RECOMMENDATIONS

A. Accident Investigations

1. The National Transportation Safety Board should be empowered, as it is in the investigation of air- craft accidents (see 49 U.S.C. §1441(c), (d)), to take pos- session of all physical evidence and to conduct, or arrange for the conduct of, all necessary and appropriate tests.

B. Inspection and Design

1. States should require their consulting en- gineers or engineering departments, on plans for bridges, to call attention to details difficult to inspect or maintain.

2. States should instruct their consulting en- gineers or engineering departments to identify and list fracture-critical members or to place references identifying the locations of such members on the bridge plans to aid inspectors in identifying them.

C. Conduct of Inspections

1. All safety inspections should be performed or monitored by engineers experienced in either design, in- spection or construction of bridges. This will assure that

-53- inspectors will have an understanding of the function of special details and will recognize any problems at a suffi- ciently early stage.

2. Inspection teams should be supplied with structural plans before and during the performance of in- spections. The plans should include not only the General

Plan and Elevation drawings but also drawings of unusual details. This preparation will enable the inspectors to make measurements, where appropriate, and to obtain suf- ficient information to permit the results of the measure- ments to be interpreted by others.

3. The inspection reporting form to be prepared by the inspectors should provide for sufficiently specific recording of the observations made by the inspectors. For example, the reporting form should provide for the recording of observations of each element in each span superstructure and each pier instead of merely the rating of the bridge as a whole. This will enable the inspector to-document the specific problems in each span. The form should also have sufficient space for remarks where appropriate. A copy of the form used in New York State is attached as an example of how such an inspection form might be structured.

-54- 4. Inspection teams should be informed of the results of their inspections, i.e., whether corrective mea- sures were taken after problems were pointed out.

D- Organization of Inspection

1. Major bridges should be inspected period- ically, for example at five- or ten-year intervals, by in- dependent outside consultants as is now done with dams sub- ject to the regulatory jurisdiction of the Federal Energy

Regulatory Commission. (See 18 C.F.R. Part 12.)

2. Independent outside consultants should be retained to review state inspection procedures and equipment requirements periodically, perhaps every five years. CONCLUSION

This proceeding was convened to assist the NTSB in determining the probable cause of the collapse of the Mianus

River Bridge on June 28, 1983, and to propound recommenda- tions for preventing similar accidents in the future. TAMS respectfully submits that the evidence gathered at the hear- ings or included in the record since then establishes that the bridge was properly designed and that the bridge's col- lapse was caused by gradual deteriorative phenomena during its lifetime. These phenomena and their e f f 6 C t S were not detected through appropriate and available inspection tech- niques, and responsive maintenance did not occur. The rec- ommendations presented above are intended to enable the NTSB to establish constructive procedures which will tend to prevent a recurrence of the tragedy that occasioned this proceeding.

Respectfully submitted,

TIPPETTS-ABBETT-McCARTHY-STRATTON

Partner

Dated: December 19, 1983

-56-