Old Masonry Buildings: Earthquake Performance and Material Testing Scrivener, J
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NRC Publications Archive Archives des publications du CNRC Old masonry buildings: earthquake performance and material testing Scrivener, J. C. For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous. Publisher’s version / Version de l'éditeur: https://doi.org/10.4224/20358650 Internal Report (National Research Council of Canada. Institute for Research in Construction), 1992-03 NRC Publications Archive Record / Notice des Archives des publications du CNRC : https://nrc-publications.canada.ca/eng/view/object/?id=3c364929-1639-4708-9989-4c99a04b9b06 https://publications-cnrc.canada.ca/fra/voir/objet/?id=3c364929-1639-4708-9989-4c99a04b9b06 Access and use of this website and the material on it are subject to the Terms and Conditions set forth at https://nrc-publications.canada.ca/eng/copyright READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE. L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site https://publications-cnrc.canada.ca/fra/droits LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB. Questions? Contact the NRC Publications Archive team at [email protected]. If you wish to email the authors directly, please see the first page of the publication for their contact information. Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à [email protected]. Council Canada de recherches Canada Institute for lnstitut de Research in recherche en Construction construction by John Scrivener Internal Report No. 624 Date of issue: March 1992 This is an internal report of the Institute for Research in Construction. Although not intended for general distribution, it may be cited as a reference in other publications. OLD MASONRY BUILDINGS - EARTHQUAKE PERFORMANCE AND MATERIAL TESTING by JOHN C SCRIVENER ABSTRACT Some of the recent earthquakes (e.g. Newcastle, Australia in 1989) have been in areas not considered to have high seismicity. Accordingly old masonry buildings in areas of supposedly low earthquake risk may be vulnerable to damage and even collapse. When they are heritage buildings the cost of damage, whether financial, historical or architectural, may be very great. Thus it is sensible to assess the risk to old masonry heritage buildings even in zones of low seismicity. The old masonry buildings covered in the review may be of stonework, clay brickwork or adobe construction. They are most often thick-walled and not reinforced. Two major areas are discussed in the review: the determination of the material and structural properties of old masonry by direct and indirect testing and the performance of old masonry in earthquakes. PREFACE The Structures Laboratory at the Institute for Research in Construction (IRC) has an ongoing research program to develop guidelines for evaluating the structural adequacy of existing buildings. Included is the seismic evaluation of older unreinforced masonry buildings. This report was prepared for the above program by Dr John Scrivener while he was on sabbatical leave at IRC from June to December 1991. He is Professor of Building in the Department of Architecture and Building, University of Melbourne, Australia. iii TABLE OF CONTENTS Section Page Abstract i Preface ii Table of Contents iii 1. INTRODUCTION. 2. MATERIAL PROPERTIES BY DIRECT MECHANIC?LG TESTS 2.1 Tests for Masonry Compressive Strength and Axial Deformation 2.1.1 Compression tests on large specimens cut out of structures 2.1.2 Compression tests on cores cut out of structures 2.1.3 Flat jack tests 2.1.4 Borehole dilatometer tests 2.1.5 Compression tests on reconstituted masonry 2.1.6 Alternative methods for determining masonry compressive strength 2.2 Tests for Mortar Properties 2.3 Tension Tests 2.4 Compression and Tension Test Results 2.5 Shear Tests 2.6 Flexural Tests 2.7 Mortar Bond Tests 3. MATERIAL AND STRUCTURAL PROPERTIES BY INDIRECT TESTS 3.1 Preliminary Investigations 3.2 Sonic and Ultrasonic Pulse Velocity Tests 3.3 Radar Method 3.4 Thermographic Analysis 3.5 Mortar Strength from Hardness Measurement 3.6 Monitoring 4. DYNAMIC TESTS 5. MODELLING OF OLD MASONRY 5.1 Static Modelling 5.2 Dynamic Modelling 6. FIELD PERFORMANCE OF OLD STONE AND BRICK BUILDINGS IN EARTHQUAKES 6.1 Larger Buildings 6.2 Smaller Buildings 7. SUMMARY AND DISCUSSION 35 7.1 Mechanical Tests for Compressive Strength and Axial Deformation 3 5 7.1.1 Direct compression tests on large specimens and cores 35 7.1.2 Flat jack testing of masonry 36 7.1.3 Borehole dilatometer test for masonry 37 7.1.4 Reconstituted masonry tests 37 7.1.5 Alternative methods for masonry compressive strength 37 7.1.6 Masonry compression test results 38 7.1.7 Mortar compression tests 39 7.2 Tension and Shear Tests 3 9 7.2.1 Tension tests 39 7.2.2 Shear tests 39 7.3 General Comments on Direct Mechanical Tests 4 0 7.4. Indirect Tests for Material and Structural Properties 40 7.4.1 Preliminary investigations and monitoring 40 7.4.2 Sonic and ultrasonic pulse tests 41 7.4.3 Radar method 41 7.4.4 Thermographic analysis 42 7.4.5 Mortar strength from hardness 42 7.5 Dynamic Tests and Modelling 42 7.6 Performance of Masonry in Earthquakes 43 7.6.1 Quality of materials and construction 43 7.6.2 Connections between structural elements 44 7.6.3 Structural layout 45 7.6.4 Soil-structure interaction 47 7.6.5 General comments on earthquake damage reports 47 8. ACKNOWLEDGEMENTS 48 9. REFERENCES CITED 48 10. REFERENCES CONSULTED BUT NOT CITED 56 11. APPENDIX 64 Table 1: Stonework compression and tension test results 64 Table 2: Brickwork compression and tension test results 65 Figure 1: Sheppard shear test arrangement 67 Figure 2:'Benussi and Mele shear test arrangement 68 1. INTRODUCTION Recently concern has been expressed on the vulnerability of older masonry building stock, particularly heritage buildings, to seismic shocks. In areas of high seismic activity, the likelihood of damage in earthquakes may be obvious. It has required the removal or strengthening of hazards such as parapets or ornaments; the strengthening ofthe building by prestressing; the incorporation of a ductile frame to which the masonry is tied; even the removal of the entire building. However in areas of low to medium seismic activity, such as eastern Canada and USA and most of Australia, while the potential for damage is less these areas may experience earthquakes sufficiently severe to cause not only loss of life but also severe damage to the fabric of buildings of historic, architectural or public importance including libraries, churches, schools and government buildings. Often the repair of such damage is expensive or it may be aesthetically impossible. There is a need to discriminate between buildings that need, and do not need, upgrading. The walls of old masonry buildings are usually thicker than those in modern buildings. Most often in stonework buildings, the exterior and interior wythes of the walls are of dressed stone with rubble in between which may or may not contain binding mortar or be bondedto the wythes. Not always is structural connection provided by through-the-wall units. Clay brick masonry walls usually have several wythes mortared together with collar joints and through- the-wall units may be used although there are some examples of construction similar to that of stonework walls. The seismic behaviour of more recent buildings of 'thin' masonry is fairly well known and understood and modern codes deal with their design and evaluation. Reinforcement is required in higher risk areas. For the older buildings in this group, evaluation has been treated by ABK (1986). Bruneau and Boussabah (1991) gave a survey of 'seismic performance of thick unreinforced masonry'. Their emphasis was on the 'seismic performance' rather than on the characteristics of 'thick masonry'. Accordingly this report is primarily concerned with testing for material properties of old stone and brick masonry and on appraisal of old masonry in earthquakes. The review is in two parts. In the first part is the determination of material properties including compressive, tensile, shear, flexural and dynamic properties of masonry, units and mortar using large specimens, cores, flat jack and borehole dilatometer tests, reconstituted masonry and alternative methods. Indirect tests, often termed non-destructive tests, such as sonic and ultrasonic pulse, radar, thermographic and mortar hardness tests are investigated. The results of many such tests are recorded. The field performance of old masonry is in the second part and the various factors causing damage, or survival, are discussed. Over 170 papers were studied in the preparation of this report. Of these, 95 papers turned out to be of direct relevance and are cited in the report and listed in Section 9, References Cited. While the other papers were not found to be of direct relevance to this report, they are sufficiently relevant to the study of seismic appraisal of old masonry buildings to warrant listing in Section 10, References Consulted But Not Cited. 2. MATERIAL PROPERTIES BY DIRECT MECHANICAL TESTS 2.1 Tests for Masonry Compressive Strength and Axial Deformation There have been several ways in which the vertical compressive strength and modulus of elasticity (E) of older masonry have been evaluated by direct tests: on large samples or on cores cut from the structure; on the structure in-situ by flat jack testing or by borehole dilatometertesting; on samples of re-constitutedmasonry; or by alternative methods.