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Technical Report No. Vol: 01/Bib/Civil/DrMGRU/2012

BIBLIOGRAPHY ON MASONRY STRUCTURES-TECHNICAL REPORT

PROF. S.SAILEYSH SIVARAJA

PROF.S.MOSES ARANGANATHAN &

PROF.T.S.THANDAVAMOORTHY

Reference for M.Tech (Struct) & PhD Scholars

DEPARTMENT OF CIVIL ENGINEERING, Dr. M.G.R Educational and Research Institute University, Maduravayal, Chennai-600 095, Tamil Nadu, India E Mail: sivaraja05@gmail.com & tan_44@yahoo.co.in

May 2012

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ABSTRACT: Considering the slow development in the research relating to masonry structures and to give an impetus and accelerate this annotated bibliography has been prepared by reviewing the available literature. This bibliography presents various aspects of research on masonry structures.

TABLE OF CONTENTS

CHAPTER No. TITLE. PAGE No.

1.0 INTRODUCTION 2

An exhaustive bibliography is of masonry structures namely bricks, mortars, cement, reinforced cement concrete, Fiber Reinforced Concrete, Polymer Concrete and construction, etc, has become a necessity to accelerate the research on this topics; Literature relating to these various aspects have been reviewed and compiled as a report here.

The following topics have been dealt with herein:

(i)Structural Brickwork

(ii) Materials Properties

(iii) Testing

(iv) Analysis and Design

(v) Dynamic Loading and Responses

(vi) Seismic Behaviour

(vii) Case Studies

(viii) Retrofitting.

The chapters on Case studies have been included to throw light on Applications aspects. Finally the chapter on Retrofitting highlights the use of different masonry system in Repair and Rehabilitation process.

The objective of this bibliographic collection is to bring under one roof all information about various masonry systems and masonry components available in open literature. Such an exercise has been necessitated as no such documents is available as at present. It is hoped that this work would serve as a useful guide for future research in the area of masonry and all aspects relating thereto.

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TABLE OF CONTENTS

CHAPTER No. TITLE. PAGE No.

2.0 STRUCTURAL BRICKWORK 04

3.0 MATERIALS PROPERTIES 07

4.0 TESTING 12

5.0 ANALYSIS AND DESIGN 25

6.0 DYNAMIC LOADING AND RESPONSES 37

7.0 SEISMIC BEHAVIOUR 46

8.0 CASE STUDIES 72

9.0 RETROFITTING 81

10.0 SUMMARY 105

11.0 REFERENCES 105

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2.0 STRUCTURAL BRICKWORK

2.1) Thomas, K., Structural Brickwork-Materials and Performance, The Structural Engineer, 1971, Vol.49, No.10, pp.441-450.

Calculated load bearing brickwork is discussed and the basic requirements are specified materials and their effects on strength and performance are considered and recommendations made. The mechanism of brickwork failure under vertical and lateral loading is covered and the results of current research in this field are included. Factors affecting strength are discussed and information is provided on composite action with concrete beams, also quality control.

2.2) Alani, A.F., EL-Katib,M.T., Ovanessian, R.A and Korkees, I.N., Structural Elevation of Load Bearing Brick Cavity Walls with Brick Ties, Journal of Structural Engineering, 1989, Vol.16, No.3., pp.85-93.

This research work forms a part of a project to investigate the structural behaviour of load bearing double wythes cavity walls built using local material and workmanship. This investigation was made using a full scale one storey height walls with brick units acting as connectors across a 50 mm cavity. The walls were subjected to both concentric and eccentric vertical loads up to failure. The eccentricity to thickness ratios ranged from 0.0 to 0.30. Twelve specimens were tested. They were divided in to three groups depending up on the type of mortar, cement: sand (1:3), Cement: lime: sand (1:1:6), and gypsum mortar (locally known as Juss mortar).Based on experimental results an empirical equation is produced to calculate the ultimate strength of storey height brick cavity walls. The theoretical results compared quite well with the test results. Comparison of results with various international design codes showed good agreement with CP111-Part 2 while both the Canadian and UBC codes show diverge results.

2.3) Toranzo, L.A., Carr, A.J and Restrepo, J.I., Improvement of Traditional Masonry Wall Construction for Use in Low Rise or Low Wall Density Building in Seismically Prone Regions, Proceeding of NZSEE Conference, 2001, pp.1/1-5/5.

The current trend of designing structures to meet performance based demands could severely limit the use of some traditional construction materials and systems. Masonry construction used in conjunction with reinforced frames, as used extensively in Latin America is among those affected. This limitation is due to the poor performance of conventional masonry system is earthquakes. This paper discusses the option of using reinforced concrete frames in-filled with masonry, acting together as a series of rocking walls providing a desired performance level. Such system may be used in buildings with a low density of elements where the demand expected in conventionally built masonry walls might result in structural damage in moderate earthquake. Rocking walls can be designed to rock while ensuring no damage will occur anywhere else in the structures. During the rocking process the system has a much lower equivalent stiffness than before rocking in triggered. Most often this means that the inertial forces are reduced as the response is shifted in to a less demanding region of the acceleration spectra. The softening of the system also lets other flexible elements participate in the response. Triggering of the rocking may be

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set for levels of excitation greater than frequent earthquakes for which the element can be designed to behave as a fixed base wall. Rocking also allows the use of hysteretic energy dissipaters at the base of the wall. It was found that these energy dissipaters could add up to 20% of equivalent viscous damping to the system.

2.4) Sarangapani, G., Venkatarama Reddy, B.V and Jagadish, K.S., Structural Characteristics of Bricks, Mortars and Masonry, Journal of Structural Engineering, Vol.29, No.2, 2002, pp.101-109.

Burnt clay bricks are widely used load bearing masonry in India. There is wide variation in the characteristics of commonly used bricks from different geographical locations of the country. For example the compressive strength vary between 2 and 24 Mpa. This paper deals with the characteristics of properties of local low modulus bricks, mortars and masonry using these materials. Bricks procured from Bangalore were tested for obtaining the properties such as compressive strength, flexure strength, water absorption, Initial Rate of Absorption (IRA), porosity and pore size and stress-strain relationships. Characteristics of two cement mortars (1:4 and 1:6) and three composite mortars (cement soil and cement lime mortars) were examined for their strength and elastic properties. Stress-strain characteristics of masonry using these bricks and mortars were determined. A simple analysis was carried out to understand the nature of stresses developed in the mortar joint and brick in the masonry. The results reveal that the bricks around Bangalore have rather low module compared to cement mortar. The brick modulus is in the range of about 5 to 10 % of the modulus of 1:6 cement mortar.This kind of situation leads to a masonry were mortar joints develop lateral tension while brick develops lateral compression (tri-axial) and this is an unfavorable situation due to the brittle nature of mortar.

2.5) Punmia, B.C., Asok Kumar Jain and Arun Kumar Jain, A Text Book of Building Construction, Lakmi Publications (P) Limited, New Delhi, India, 2006.

Man requires different types of buildings for his activities: houses, bungalows and flats for living; hospitals and health centers for his health; school colleges and universities for his education; banks, shops, offices, buildings and factories for doing work; railway buildings, bus stations and air terminals for transportation; clubs, theatres and cinema houses for re-creation and temples, mosques, churches, darmashalas etc, for worship. Each type of the above buildings has its own requirements. The above building activities are an important indicator of the countrys social progress.

2.6) Ana Radivojevi and Nadja Kurtovi-Foli, Evolution Of Bricks And Brick Masonry In The Early History Of Its Use In The Region Of Todays Serbia, Journal of Materials in Civil Engineering, 2006, Vol. 18, No. 5, October 1, pp692699

Brick was proved to be one of the main building materials in the region of todays Serbia, especially in the time of late antiquity and in the following medieval time. Hence, the idea was born to make a comparison between the main characteristics of late antique and medieval bricks and brickworks from this region that could confirm the continuity and variety of its use. A question of evolution of the use of bricks was partly based on comparison of their estimated properties and also on comparison of applied building techniques and known characteristics of brick production. It has been

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confirmed that although it is possible to discuss and confirm the continuity in the use of bricks and adequate building techniques, up-to-date research based on quantitative analysis of historical bricks do not offer enough comparable data regarding their quality. There-fore a new field of possible qualitative research is needed in the future.

2.7) Manjunath.S, Renuka Devi. M and K.S.Jagadish, Strength Of Hollow Block Masonry Walls, 2009-10, Research Centre : R.V.College of Engineering, India.

Masonry has been used as a basic construction material for public and residential buildings in the past several thousand years; from the tower of Babylon ,to the great wall of china, which is the only man made structure visible from the moon. A number of well preserved old masonry building still exist, proving that masonry can successfully resist loads and environmental impacts, therefore providing shelter for people and their goods for a long period of time, if adequately conceived and constructed. Although some specific features have been invented during the course of time to improve the seismic behavior of masonry buildings , such as connecting stones, strengthening of the corners and wall intersection zones, as well as tying of the walls even today, masonry construction represents the most vulnerable part of existing building. This is not only in the case of developing or underdeveloped countries but it is also in the case of some of the developed countries of Europe and the USA.

2.8) Maria P. Durante Ingunza, Anaxsandra C. L. Duarte and Rubens M. Nascimento, Use Of Sewage Sludge As Raw Material In The Manufacture Of Soft-Mud Bricks, Journal of Materials in Civil Engineering, 2011, Vol. 23, No. 6, June-1, pp852856

This article assesses the use of sewage sludge as a raw material in the ceramic industry, specifically in the manufacture of soft-mud bricks, to determine the maximum incorporation of sludge that results in technically sound and environmentally friendly bricks. The results obtained confirm that there was no alteration in the odor of the bricks, even at high proportions of sludge; however, high concentrations of sludge had a negative influence on certain properties, such as mechanical strength and absorption. Compressive strength was significantly diminished with the addition of sludge: the bricks with 5% sludge lost an average of 45% of the strength obtained by the control brick; the bricks manufactured with 15 and 20% lost around 70% of maximum strength; however, they still met minimum strength standards. For the specified conditions of this study, it was concluded that 20% was the maximum proportion of sludge that could be incorporated into a ceramic mass and still meet technical and environmental requirements.

2.9) Jianhai Liang and Ali M. Memari, M.ASCE, Introduction Of A Panelized Brick Veneer Wall System And Its Building Science Evaluation, Journal of Architectural Engineering, 2011, Vol. 17, No. 1, March 1, pp114

This paper introduces a panelized brick veneer over steel stud backup wall system to address some of the shortcomings of conventional systems. Thermal and hydrothermal analyses of the proposed wall system with different stud gauges and arrangements are discussed. The movement joint design aspects, a pressure moderation performance evaluation, the simulated wind-driven water penetration results, and an example cost analysis are also presented. This study provides information about some of the attributes of the proposed system such as crack

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resistance and water penetration potential as well as the pressure moderation aspect. Some of the issues that need consideration for the practical application of the system are also described.

3.0 MATERIAL PROPERTIES:

3.1) Krishna Naraine and Sachchidanand Sinha, Loading And Unloading Stress-Strain Curves For Brick Masonry, Journal of Structural Engineering, 1989, Vol. 115, No. 10, pp2631-2644

Reloading and unloading stress-strain curves of brick masonry tested under uniaxial cyclic compressive loadings perpendicular and parallel to the bed joint are discussed. A simple mathematical model is proposed to predict these curves at different values of plastic strain. An exponential relationship involving the axial stress, the axial strain, and the plastic (residual) strain is found to be appropriate to represent the reloading and unloading curves. It is shown that the reloading curves can be mathematically represented by a family of parabolas and the unloading curves can be similarly represented by a family of straight lines. The equations of a parent parabola and a parent straight line are used to generate the family of parabolas and the family of straight lines respectively. The families of parabolas and straight lines can then be used to compute the reloading and unloading curves respectively. Comparisons of the model predictions with the experimental reloading and unloading curves show very good agreement.

3.2) Deodhar, S.V and Patel, A.N., Behaviour of Brick Masonry in Compression, Journal of Structural Engineering, 1996, Vol.22, No.4, pp.221-224.

Brick masonry has been used from time immemorial for construction of low- rise residential buildings and columns etc., to resist compressive loads. The strength of masonry depends on the strength of brick, mortar and adhesion between the two, joint thickness and various other factors. Thus for the same type of brick, using same proportion of cement and sand, the strength obtained may differ to due to variation in quantity of water, difference in workshop, arrangement of bricks and many other reasons. Under the compressive load, mortar deforms laterally and squeezes out causing cracks at joints. Some additives in mortar increase the adhesion at the brick faces, increasing the strength. However clay content in sand decreases the adhesion, and consequently the strength of masonry. The other factor that affects the strength is joint thickness. The adhesion between brick and mortar depends upon the effective. Transfer to matrix between these two materials, which in turn depends upon appropriate thickness of mortar joint used for bonding the bricks. The size of brick is also one of the important factors that may affect the strength of brick masonry. The brick that was commonly used in early 1960's was quite thin (25 to30mm) whereas present practice is to use thicker bricks. Large brick size reduces number of mortar joints which are the weak parts in masonry. Minimization of mortar joins is likely to increase the strength and makes masonry more economical and reduces the overall cost of construction. Frog plays an important role in bonding the brick work. Shape and size of frog may affect the strength of brick masonry to certain extent. It is presumed that rendering over masonry is incorporated to prevent the effect of atmospheric agencies on brick masonry. However if masonry is raked at

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the joints and rendering is provided, there is every possibility of increasing the load carrying capacity of brick masonry. With all these parameters in mind an experimental programme was undertaken to study the effect of these parameter on crushing strength of masonry and conclusions are reported.

3.3) Deodhar, S.V and Patel, A.N., Strength Relationship of Brick Masonry Brick and Cement Mortar, Journal of Structural Engineering, 1997, Vol.23, No.4, pp.215-218.

Brick and brick masonry have been used extensively in building construction for many centuries and continues to dominate as the commonly used construction material either as a load bearing or as a filler wall. It is further well established that if good quality bricks having crushing strength more than 10.50 N/mm2 are bonded in 1:3 cement-sand mortar for ground and first floor and in 1:6 cement mortar for third and fourth floor, a four storied building can be constructed with 225 mm thick brick wall, using conventional brick.

3.4) Jagadish, K.S., Basic Structural Properties of Masonry, Proceeding of the Workshop on Recent Advances in Masonry Construction, Rookie, India., 1998., pp.41-52.

Use of brick masonry has been known, especially in India, for nearly 5000 years. Even in other countries brick masonry has been in use for more than thousand years. However, the earliest recent material like concrete has received far greater attention by the Civil Engineer. For instance, research papers on concrete are found as early as in 1907. However, the earliest report on brick masonry was produced in 1918. The paucity literature in the Indian context is also striking, in spite of the fact that a few sporadic attempts were made to study brick masonry since the mid sixties. The problem of brick masonry in India is compounded by the fact that bricks and mortars vary widely in character in different regions. The situation is very different from that of concrete.

3.5) Milad m. Alshebani and s. N. Sinha, Stress-Strain Characteristics Of Brick Masonry Under Uniaxial Cyclic Loading, Journal of structural engineering, 1999, vol.125, no.6, pp600-604

A series of laboratory tests were carried out on half-scale sand plast brickwork panels subjected to uniaxial cycle loading. Forty-two square panels were tested under cycle loading until failure for two cases of loading: (1) Normal to the bed joint; and (2) parallel to the bed joint. Failure due to cyclic compressions was usually characterized by a simultaneous failure of brick units and head joints or by splitting in the bed joints depending on whether the panel was loaded normal or parallel to the bed joint, respectively. The characteristics of the stress-strain relationship of the two loading conditions are presented in this paper. Envelope, common point, and stability point stress-strain curves were established based on test data, and an exponential formula was found to provide a reasonable fit to the test data. It was concluded that the peak stress of the stability point curve can be regarded as the maximum permissible stress level that is found to be approximately equal to two thirds of the failure stress. It was also observed that the permissible stress level depends on the plastic strain level present in the material due to cyclic loading.

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3.6) F. M. Khalaf and a. S. Devenny, New Tests For Porosity And Water Absorption Of Fired Clay Bricks, Journal Of Materials In Civil Engineering, 2002, Vol. 14, no. 4, august 1, pp334-337

The porosity of bricks, and their permeability and absorption are very important factors in influencing properties of bricks such as the bond between them and mortar, the resistance of bricks to freezing and thawing, and their chemical stability. This paper suggests new tests for calculating the porosity and water absorption values of clay bricks, which involve the testing of 20-mm brick lumps instead of full brick units.

3.7) Asteris, P.G., Lateral Stiffness of Brick Masonry In-Filled Plane Frames, Discussion and closures, Journal of Structural Engineering, 2003, Vol.129, No.8, pp.1071-1079.

The author investigates the lateral stiffness of in-filled frames, particularly focusing on the reduction of stiffness due to opening. The finite element method is used to analyze various configuration. Infill behaviour in itself is quite complex and openings add to the complexity of the problem. Thus the author is to be commended for examining problem.

3.8) Bryan D. Ewing and Mervyn J. Kowalsky, Compressive Behavior Of Unconfined And Confined Clay Brick Masonry, Journal of Structural Engineering, 2004, Vol. 130, No. 4, April 1, pp650-661

Presented in this paper are the results of an investigation of the compressive behavior of grouted clay brick masonry prisms. The objective is to experimentally capture the stressstrain characteristics of unconfined and confined clay brick masonry and compare the response with that predicted with the modified KentPark stressstrain curve. Based on the experimental results, five limit states for clay brick masonry in compression are proposed, as well as equivalent stress blocks for design. Thin galvanized steel plates placed in the mortar joints during construction provided prism confinement. The variables considered included volumetric ratio of confining steel ~0, ;0.015, and ;0.03! and the presence of machined holes within the confinement plates to improve the bond between the masonry and steel plate. It is shown that confinement plates are extremely effective in enhancing the ultimate compressive strength as well as increasing the deformation capacity of the clay brick masonry prisms. The use of confinement plates in the test increased the ultimate compression strength by 40%. Failure of the confined masonry prisms occurred simultaneously or immediately after yielding of the confinement plates. Experimentally obtained stressstrain curves agreed reasonably well with the modified KentPark model.

3.9) Peter J. Walker, Strength And Erosion Characteristics Of Earth Blocks And Earth Block Masonry, Journal of Materials in Civil Engineering, 2004, Vol. 16, No. 5, pp497-506

The paper describes methods currently used for strength and erosion resistance testing of earth blocks. Following this, an experimental study undertaken to assess the

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influence of test procedure and specimen geometry on strength and erosion characteristics is presented. Cement stabilized pressed earth blocks were fabricated using different blended soils and compacted using a constant volume manual press. The effects of specimen geometry on experimental compressive strength are described and aspect ratio correction factors for unconfined unit strength outlined. Proposals for a unified approach to compression strength testing are also suggested. Bending strength testing is commonly used as an indirect method of strength assessment, as it is more readily suited to in-situ quality control testing than compression testing. The experimental correlation between compressive and bending strengths is presented. Results of compression tests on masonry walls are also presented together recommendations for design. Finally, the influence of test method and specimen geometry on erosion resistance and the correlation with block strength is discussed.

3.10) Fouad M. Khalaf and Alan S. DeVenny, Performance Of Brick Aggregate Concrete At High Temperatures, Journal of Materials in Civil Engineering, 2004, Vol. 16, No. 6, December 1, pp556565

This paper presents the results of an experimental investigation into the effects of high temperatures on the properties of concrete made with crushed clay bricks as the coarse aggregate. Two types of brick of different strength were crushed to coarse aggregate that was used to produce concretes of different strength. Natural granite aggregate was also used to produce concretes in order to compare results. The paper presents the results for brick unit uniaxial compressive strength, aggregate impact value, aggregate relative density, brick and aggregate water absorption, aggregate porosity, concrete density, and concrete strength before and after exposure to high temperatures. The results showed that concrete could be produced using crushed clay bricks as the coarse aggregate and at high temperatures clay brick concrete preformed similar or even better than granite concrete.

3.11) Michele Dondi, Francesca Mazzanti, Paolo Principi, Mariarosa Raimondo and Giorgio Zanarini, Thermal Conductivity Of Clay Bricks, Journal of Materials in Civil Engineering, 2004, Vol. 16, No. 1, February 1, pp814

In the present work the thermal conductivity of 29 samples of clay bricks was measured and the correlations of the thermal performance with the compositional, physical, and micro structural features of products were investigated. The results obtained directed our attention toward a better understanding of the role played by some parameters ~i.e., mineralogical components and pore size distribution!, other than bulk density, in improving or depressing the insulating properties of bricks. Among them, the unfavorable role of quartz, Ca-rich silicates, and amorphous phase came out, while the role of pore size and specific surface should be more accurately evaluated in the structural design of materials.

3.12) Fouad M. Khalaf and Alan S. DeVenny, Properties Of New And Recycled Clay Brick Aggregates For Use In Concrete, Journal of Materials in Civil Engineering, 2005, Vol. 17, No. 4, August 1. pp456-464

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The testing described in this paper was performed to establish the physical and mechanical properties of new and recycled crushed clay brick aggregates for use in portland cement concrete ~PCC!. Various physical and mechanical properties of eight different types of aggregates were determined and compared with the limits set out in the British Standards for aggregate from natural sources used in concrete. The results were also compared with granite aggregate that has been proved to be a good natural aggregate for producing PCC. The results showed that most of the crushed clay-brick aggregates tested can be used in producing PCC for low-level civil engineering applications and that some kinds of brick aggregate possess good physical and mechanical properties that qualify them for producing high-quality concrete.

3.13) Vijayalakshmi, M.M and Shanmugasundaram, V., Innovative Building Materials and Methods for Better Thermal Performance of Residential Buildings, In: Proc, Proceedings of National Conference on Innovative Technologies in Civil Engineering March 20 & 21, Department of Civil Engineering, (Edi) K.Subramanian, V.G.Srisanthi and M.P.Muthuraj, Coimbatore Institute of Technology, Coimbatore, India, 2006, pp.309-318.

Energy is an important necessity for the growth of a society. Energy required per capita continuously increases and it results in serious implications on pollution, climate change and resource depletion. Making houses energy efficient leads to a reduction in the amount of energy used. Efficient use of energy will pave way for sustainable development, as it results in better utilization of energy and less pollution.

3.14) Amuthakkannan, R., Yogendran, B and Vijayalakshmi, K., Measurement of Various Building Parameters using Virtual Instrumentation and Image Processing Technique, In: Proc, Proceedings of National Conference on Innovative Technologies in Civil Engineering March 20 & 21, Department of Civil Engineering, (Edi) K.Subramanian, V.G.Srisanthi and M.P.Muthuraj, Coimbatore Institute of Technology, Coimbatore, India, 2006, pp.473-480.

Nowadays virtual Instrumentation systems (Software based Instrumentation) are used in various fields, such as Business Core Transactions, Modern Cars, Automated Teller Machine (ATM), Air craft Control Systems, Nuclear Power Plants, Manufacturing Industries etc. In the modern buildings, It is very essential to predict the various parameters such as temperature, humidity, vibration, length, breadth and height accurately to control the various problems like acoustics, overload, over heat etc., The virtual Instrumentation technique is a software based measurement and control system using the software Lab View.

3.15) Chakraverty, S., Saini, H and Panigrahi, S.K., Predicting Product Parameters of Fly Ash-Cement- Sand-Bricks, Construction Materials, 2007, Vol.160, No.CM2, pp.65-74.

This paper discuss models with ternary systems of fly ash, cement and sand by using simplex lattice and simplex centroid design for building bricks. A statistical design with upper and lower bounds of three component mixtures was adopted to select the mixture proportions of experimental points required for prediction of the product parameters, namely compressive strength, bulk density and water absorption of cement fly ash bricks. The experimental points include the process parameters such as

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percentage of fly ash, cement and sand and the corresponding product parameters at different curing periods. Regression models of various orders for the above design methods are developed.

3.16) A. Arulrajah, J. Piratheepan, T. Aatheesan and M. W. Bo, Geotechnical Properties Of Recycled Crushed Brick In Pavement Applications, Journal of Materials in Civil Engineering, 2011, print April 7, doi:10.1061 (ASCE-In Press)

This paper presents the findings of a laboratory investigation on the characterization of recycled crushed brick and an assessment of its performance as a pavement sub base material. The properties of the recycled crushed brick were compared with the local state road authority specifications in Australia to assess its performance as a pavement sub-base material. The experimental programme was extensive and included tests such as particle size distribution, modified Proctor compaction, particle density, water absorption, California Bearing Ratio, Los Angeles abrasion loss, pH, organic content, static triaxial and repeated load triaxial tests. California Bearing Ratio values were found to satisfy the local state road authority requirements for a lower sub-base material. The Los Angeles Abrasion Loss value obtained was just above the maximum limits specified for pavement sub-base materials. The repeat load triaxial testing established that crushed brick would perform satisfactorily at a 65% moisture ratio level. At higher moisture ratio levels shear strength of the crushed brick was found to be reduced beyond the acceptable limits. The results of the repeat load triaxial testing indicate that only recycled crushed brick with a moisture ratio of around 65% is a viable material for usage in pavement subbase applications. The geotechnical testing results indicates that crushed brick may have to be blended with other durable recycled aggregates to improve its durability and to enhance its performance in pavement sub-base applications.

4.0 TESTING

4.1) Alani, A.F., El-Katib, M.T., Ovanessian, R.A and Korkees, I.N., Cavity Load Bearing Brick Wall with Steel and Brick Ties, Journal of Structural Engineering., 1990, Vol.16, No.4, pp.101-108.

This research paper reports the results of vertical load test on nine full scale double leaf brick cavity walls. Masonry mortar 1:1:6 (cement: lime: sand) was used as a binding material in the construction of wall. Two types of ties, brick and standard steel ties were used to connect the leaves across a 50 mm cavity. One cavity wall specimen without ties was studied in the test program. The walls were subjected to vertical loading, both concentric and eccentric; to investigate their behaviour and ultimate load carrying capacities, with eccentricity to thickness ratios (e/t) from 0.00 to 0.30. Test results show that walls with brick connectors had slight overall improvement in structural behaviour in terms of ultimate and capacities, moment curvature relationships, lateral deflections, and tie slippage, when compared to walls built with British standard steel connectors. Comparison between theoretical and experimental results are also given

4.2) R. Wang, A. E. Elwi, M. A. Hatzinikolas and J. Warwaruk, Tests Of Tall Cavity Walls Subjected To Eccentric Loading, Journal of Structural Engineering, 1997, Vol. 123, No.7, pp0912-0919

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This paper presents a test program on full-scale reinforced slender shear connected cavity walls subjected to an eccentric compressive loading. A total of nine walls were tested. All specimens were constructed with a partially grouted andreinforced, 190-mm concrete masonry block wythe and a 90-mm burnt clay brick wythe. All had a slenderness ratio of height to backup wythe thickness of 27.8 and, except for one specimen, all walls had a 75-mm wide cavity. The primary variable, was the axial force eccentricity. The eccentricity varied both in magnitude from tl2 to t/3, and in direction, either towards or away from the brick wythe. Some walls were tested with a single curvature, others were tested in double curvature. The load-displacement response, failure mode, and ultimate load capacities are examined and reported along with the observation and discussion.

4.3) Qamaruddin, M and Mauroof, A.L.M., A New Model for Lateral Stiffness of Shear Walls with Openings, Journal of Structural Engineering, 1998, Vol.25, No.2, pp.103-107.

In masonry structures, the walls are designed to carry both the vertical and lateral loads. The magnitude of lateral load carried by each wall depends on its relative stiffness compared to overall stiffness of the structure. Although, various methods are known for the computation of the lateral stiffness of shear walls subjected to lateral loads resulting from wind and earthquakes, the presence of openings with appreciable percentage of total area of the wall, greatly affects the stiffness of the wall. Existing methods assume fixity at the pier-spandrel junction of the wall piers to estimate their stiffness. A new method is proposed in this paper which considers the flexibility of the diaphragm/spandrel at the top/bottom of the piers in estimating the lateral stiffness of the wall. Results obtained by the proposed method and the finite element method indicate excellent agreement.

4.4) Manamohan Kalgal, R and Prakash, M.R., Effect of Joint Thickness on Compressive Strength of Stack Bonded Prisms-A Preliminary Investigation, Tech. Report, Dept of Civil Engineering Department, M.S.Ramaiah Institute of Technology, Bangalore, India, 1998, pp.96-101.

Strength and thickness of mortar bed joint play vital role in strength and behavior of the masonry. The paper outlines an experimental study undertaken to investigate the effect of joint thickness on the strength of masonry prisms. The factors considered are (a) types of mortar- cement mortar and soil-cement mortar, (b) thickness of mortar bed joint and (c) type of masonry unit bricks and soil cement blocks. The investigation is aimed at studying the variation in the strength and mode of failure.

4.5) Matey, M.B., Strength and Behaviour of Concrete Hallow Block Masonry Walls in Compression, Tech. Report, Civil Engineering dept, Visveshvaraya Regional College of Engineering, Nagpur, India, 1998, pp.102-106.

This paper includes the characteristics of material used for investigation, method of producing structurally efficient hollow blocks, construction of wall panels, detailed test procedure and the test results. The main aim of the investigations is to study slenderness ratio parameter for hollow block wall panels under uniformly distributed compressive load. Total ten panels of different height are tested . The end condition of

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all the wall panels is same. The relation between stress reduction factor and slenderness ratio is compared with the values in I.S. and experimental results. The other parameters studied are ratio of wall strength to block strength, ratio of experimental ultimate load to theoretical permissible load on wall, stress-strain relationship, strain distribution at the blocks and along the height of the walls and cracking and failure pattern of wall panels. Behavior of walls was also observed during application of gradually increasing uniformly distributed load. It was observed that the wall panels failed by vertical cracking followed by cracking of mortars joints, blocks and stripping of face panels of blocks. It was observed that the strain along perpend mortar joints was more than that of bedding mortar joints. The average ratio of wall strength to block strength was found to be 0.71. The ratio of experimental ultimate load to theoretical permissible load on walls was found to be 7.32. The stress reduction factor given in I.S. Code was found to be higher than experimental results for corresponding slenderness ratio.

4.6) Sarangabani, G and Sajid, S.A., Compressive Strength and Geological Characteristics of Natural Building Stones, Tech. Report, Dept of Civil Engineering, NIT., Mysore, India, 1998, pp.107-109.

This paper deals with the determination of compressive strength and geological characteristics of natural building stones. Stones from twelve different locations have been considered in this experimental investigation. An attempt has also been made to correlate the geological characteristics to the compressive strength of the stones.

4.7) Walker, P., Strength and Durability Testing of Earth Blocks, Tech. Report, Dept of Architecture and Civil Engineering, University of Bath, UK, 1998, pp.110-118.

The paper describes methods currently used for compressive and bending strength testing of earth blocks. An experimental program undertaken to consider the influence of both test procedure and specimen geometry on unit compressive strength is outlined. Un-stabilized and cement stabilized compressed earth blocks have been fabricated using different blended soils and compacted using a constant volume manual press. The effects of specimen geometry on experimental compressive strength are described and aspect ratio correction factors for unconfined unit strength are outlined. Proposals for a unified approach to compressive strength testing are also suggested. Bending strength testing is commonly used as an indirect method of strength assessment, as it is more radialy suited to in-situ quality control testing than compression testing. The experimental correlation between compressive and bending strength is presented and general guidelines for flexural testing are also proposed. Finally, the correlation of strength with other important characteristics, such as erosion resistance, is presented.

4.8) Santos, F.A., Sinha, B.P and Roman, H.R., Lateral Behaviour of Masonry Shear Wall with Filled and Unfilled Vertical Mortar Joints, Tech. Report, Dept of Civil Engineering, University of Edinburgh & Santa Catarina, UK & Brazil, 1999, pp.164-170.

This paper describes an investigation carried out to study the behaviour of masonry shear wall structures under lateral loading. A series of experiments were carried out

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on 1/3-scale masonry structures with filled and unfilled vertical mortar joints. Deflection and strains were measured during the experiment. Finite Element analysis was carried out, which gives very good agreement with experimental results provided the orthotropic properties of masonry is taken into account. Considering masonry as isotropic will underestimate the top deflection and the stresses along the wall at the bottom. From the experiments it seems that the strain along the length of shear wall is non-linear even at very low level of the shear load.

4.9) Sivarama Sarma, B., Sreenath, H.G., Bhagavan, H.G., Vimalanandam, V., Experimental Studies on Un-reinforced and Reinforced Masonry Panels under In-plane Monotonic Lateral Loads, Tech. Report, Structural Engineering Research Center., Chennai., India, 1999, pp 187-192.

The code of practice for earthquake resistant design of buildings, IS: 1893, is being revised with the concepts of ductility based design. Shear wall are the main structural elements that resist the in plane lateral loads developed due to seismic action. The strength and ductility characteristics of shear walls vary predominantly with the amount of horizontal and vertical reinforcement, type of masonry panel, strength of block or brick and mortar, fixed at base etc. This paper lists the summary of various tests carried out on hollow concrete blocks, bricks, prisms and wall panels incorporating conventional bricks and structural grade hollow concrete blocks under in plane monotonic lateral load, along with super imposed gravity loads. Force reduction factors useful for seismic strength design are also derived. The experimental results indicate that the reinforcement in masonry shear wall improves the ductility, and shear load characteristics. The shear stress results are also compared with permissible values as given in BS: 5628-1995, ACI: 530-95 and IS: 1905-1987

4.10) Aishebani, M.M and Shina, S.N., Stress-Strain Characteristics of Brick Masonry under Uni-axial Cyclic Loading, Journal of Structural Engineering, 1999, Vol.125, No.6, pp.600-604.

A series of laboratory tests were carried out on half-scale and plast brick work panels subjected to uni-axial cycle loading: (1). Normal to the bed joint; (2). Parallel to the bed joint. Failure due to cyclic compressions was usually characterized by a simultaneous failure of brick units and head joints or by splitting in the bed joints depending on the weather the panel was loaded normal or parallel to the bed joint, respectively. The characteristics of the stress-strain relationship of the two loading conditions are presented in this paper. Envelope, common point, and stability point stress strain curves were established based on test data, and an exponential formula was found to provide a reasonable fit to the test data. It was concluded that the peak stress of the stability point curve can be regarded as the maximum permissible stress level that is found to be approximately equal to two thirds of the failure stress. It was also observed that the permissible stress level depends on the plastic strain level present in the material due to cyclic loading.

4.11) Choubey, U.B., Gupta, U and Maidasani, A., An Experimental Study of Flexural Tensile Strength Calcium Silicate Brick Masonry, Journal of Structural Engineering, 1999, Vol.26, No.2, pp.143-148.

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Brick panels used essentially as claddings for buildings, have to withstand lateral wind pressure besides other loads. The results of the experiments show that the tensile bond strength is affected by the moisture content of brick. It almost reduces to zero if the bricks are saturated at the time of laying. On the contrary, if brick is dry and has high suction rate, there will be a partially hydrated zone in the cement paste up to a depth of several millimeters. Experiments on the interaction between brick and cement paste have shown that the mechanical bond between these components is considerably affected by their specific surfaces and capillary dimensions. In a physical- chemical process a micro layer of ettringite is formed at the interface and tensile bond strength is critically affected by the respective mean diameter of the pores of the brick and of the micro crystals of the ettringite. It is necessary that the pore size of the brick material to be greater than 0.05 mm for a mechanical bond to be formed and also for the cement to be properly hydrated behind the ettringite layer.

4.12) Alessandra Aprile, Andrea Benedetti and Fabio Grassucci, Assessment Of Cracking And Collapse For Old Brick Masonry Columns, Journal of Structural Engineering, 2001, Vol. 127, No. 12, December, pp14271435

This paper presents experimental and theoretical research focused on the structural behavior of old brick masonry columns. To gather data on the role played by the evolution of brick-mortar interaction stresses when the load is increasing up to failure, six prototype columns made with 17th century bricks and lime mortar were prepared and tested. The instrumentation layout allowed the writers to carefully detect the cracking load and to pick out some selected strain values. Afterward, the obtained data were discussed on the basis of the well-known hypotheses characterizing the masonry stress fields and collapse events. A simple modification of the classical Hilsdorf equilibrium equation motivated by the observed experimental behavior led to a sensible interpretation of the nested phases of brittle failure endured by the masonry up to the collapse. In order to account for the changing interaction stress between mortar layers and brick courses, an influence factor was defined to restore the internal equilibrium during the evolution of the column damage states. In fact, the introduced mortar influence factor holds an important position in the definition of the margin between the cracking and global failure phases, explaining why the collapse load of the column is higher than the first cracking load. Moreover, thanks to some simplifications in the analyses, it was shown that this key parameter plays the role of a strength amplification factor linked to the damage evolution, and that consequently it can be used in the approximate evaluation of the remaining reliability of the masonry column after the stabilized cracking phase.

4.13) Hall, J.D., Schuman, P.M and Hamilton, H.R-III., Ductile Anchorage for Connecting FRP Strengthened of Under Reinforced Masonry Building, Journal of composites for construction., 2002, Vol.6, No.1, pp.3-10.

Fiber reinforced polymer (FRP) composites have been examined as a convenient and cost effective means of strengthening un-reinforced structures. Seismic design in the United States is almost entirely based on the assumption that the structural systems provides a ductile failure mode. FRP strengthened masonry walls inherently have brittle failure modes due to the nature of the strengthening system. The concept explored in this article is the introduction of ductility using a hybrid strengthening system. This involves the placement of structural steel or reinforcing steel at critical

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locations in the lateral force resisting system. This article presents the testing and analysis of a ductile structural steel connection that can be used to strengthen the connection of FRP strengthened shear walls to the foundation. The connection also increases energy dissipation. Results indicate that a ductile failure mode can be attained when the connection is designed to yield prior to the failure of the FRP strengthening.

4.14) Asteris, P.G., Lateral Stiffness of Brick Masonry In-Filled Plane Frames, Discussions and closures, Journal of Structural Engineering, 2003, Vol.129, No.8, pp.1071-1079.

The author investigates the lateral stiffness of in-filled frames, particularly focusing on the reduction of stiffness due to opening. The finite element method is used to analyze various configuration. Infill behaviour in itself is quite complex and openings add to the complexity of the problem. Thus the author is to be commended for examining problem .

4.15) Michael Craig Griffith, nelson t. k. lam, john leonard wilson and kevin doherty, Experimental Investigation Of Unreinforced Brick Masonry Walls In Flexure, journal of structural engineering, 2004, vol. 130, no. 3, march 1, pp423432

This paper presents the results of static and dynamic tests on unreinforced brick masonry wall panels subject to out-of-plane loading. Fourteen wall panels were tested. The test program included static, free-vibration, and dynamic tests using harmonic support, impulse support, and earthquake support motion. The experimental results indicate that displacement, rather than inertia force amplitude, determines whether an unreinforced masonry wall will collapse during inertial ~seismic! loading. An empirical forcedisplacement relationship is proposed that can be used for a substitute structure in a displacement-based method of analysis.

4.16) Ghobarah, A and Galal, K.E.M., Out-of-Plane Strengthening of Un-reinforced Masonry Walls with Openings, Journal of Structural Engineering, 2004, Vol.8, No.4, pp.298-305.

Collapse of un-reinforced masonry (URM) walls is the cause of many casualties during extreme loading events. The objective of this current research was to investigate effective and practical approaches for strengthening URM block walls with openings to resist extreme out-of-plane loads. Five full-scale masonry block walls were constructed. The walls had different opening configurations such as a single center window, one window off center, two windows, a wide window and a door. The walls were tested when subjected to uniformly distributed lateral load up to failure. The walls were then strengthened using carbon fiber-reinforced polymer laminate strips and then re-tested. The walls were set up in a vertical test frame and were subjected to cyclic out-of-plane distributed pressure using an airbag. Failure of the un-strengthened URM block wall was along the mortar joints. In the strengthened walls, failure occurred in the mortar joints as well as in concrete blocks near the carbon strips. The lateral load carrying capacity of the strengthened walls was found to be significantly higher than that of the un-strengthened walls and had much more ductile performance.

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4.17) Griffith, M.C., Lam, N.T.K., Wilson, J.L and Doherty, K., Experimental Investigation of Un-reinforced Brick Masonry Walls in Flexure, Journal of Structural Engineering, 2004, Vol.130, No.3, pp.423-432.

This paper presents the results of static and dynamic tests on un-reinforced brick masonry wall panels subject to out-of-plane loading. Fourteen wall panels were tested. The test program included static, free-vibration, and dynamic tests using harmonic support, impulse support, and earthquake support motion. The experimental results indicate that displacement, rather than inertia force amplitude, determines whether an un-reinforced masonry wall will collapse during inertial (seismic) loading. An empirical force displacement relationship is proposed that can be used for a substitute structure in a displacement based method of analysis.

4.18) Tan, K.H and Patoary, M.K.H., Strengthening of Masonry Walls against Out-of-Plane Loads using Fiber-Reinforced Polymer Reinforcement, Journal of Structural Engineering, 2004, Vol.8, No.1, pp.79-87.

Thirty masonry walls strengthened using three different fiber-reinforced polymer (FRP) systems, with three anchorage methods, were fabricated and tested under a concentrated load over a 100 mm square area or a patch load over a 500 mm square area. The test results indicated a significant increase in the out-of-plane wall strength over the un-strengthened wall. While failure occurred in the un-strengthened wall by bending, four different mode failure, that is punching shear through the bricks, de-bonding of FRP reinforcement from the masonry substrate, crushing of bricks in compression, and tensile rupture of FRP reinforcement, were observed in the strengthened walls, depending on the types and configuration of FRP and anchorage systems. With appropriate surface preparation and anchorage systems, premature failure due to FRP de-bonding is prevented. Based on the principles of strain compatibility and force equilibrium, simple analytical models are presented to predict the ultimate load carrying capacity of the strength.

4.19) Paquette,J., Bruneau, M and Brzev, S., Seismic Testing of Repaired Un-Reinforced Masonry Building having Flexible Diaphragm, Journal of Structural Engineering, 2004, Vol.130, No.10, pp.1487-1496.

The In-plane rocking behaviour of un-reinforced masonry walls is generally perceived as a stable desirable behaviour. However, there may be instances where the available lateral resistance of such walls would be in-adequate. In that perspective, fiberglass strips were applied to damaged un-reinforced masonry (URM) shear wall to increase theie inplane lateral load resisting capacity. This paper reports on the dynamic response and behaviour of the full scale one story un-reinforced brick masonry building specimen having a flexible wood floor disphragm.

4.20) Moerman, W., Taerwe, L., Waele, W.D., Degrieck, J and Himpe, J., Measuring Ground Anchor Forces of a Quay Wall with Bragg Sensors, Journal of Structural Engineering, 2005, Vol.131, No.2, pp.322-328.

The use of optical fiber sensors for monitoring civil engineering structures is increasing continuously. One of the most frequently applied sensor types is the so called Bragg sensors, which is primarily used to measure structural deformations. Due

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to some inherent advantages these sensors are ideally suited for long term monitoring purposes. This paper describes the development of the load cell, based on Bragg sensors, to measure the forces in the ground anchors of the quay wall. The test results compared well with the analytical predictions.

4.21) Mullins, G., Sen,R., Suh, K and Winters, D., Underwater Fiber Reinforced Polymers Repair of Pre-stressed Piles in the Allen Creek Bridge, Journal of Composites for Construction, 2005, Vol.9, No.2, pp.136-146.

This paper presents an overview of a demonstration project in which corroding pre-stressed piles located in tidal waters were wrapped underwater using carbon and glass fiber reinforced polymer material. An innovative instrumentation scheme was developed to allow assessment of the pre-wrap and post-wrap corrosion state using linear polarization. This system is simple to install and eliminate the need for wiring and junction boxes, the underwater wrap used to unique water activated urethane resin system that eliminated the need for cofferdam construction. Linear polarization measurements taken before and after wrapping indicate that the corrosion rate in the wrapped specimens is consistently lower than those in its un-wrapped counterpart. These preliminary findings are encouraging and suggest that underwater wrapping without cofferdam construction may provide a cost effective solution for pile repair.

4.22) Antoniades, K.K, Salonikios, T.N and Kappos, A.J., Tests on Seismically Damaged Reinforced Concrete Walls Repaired and Strengthened using Fiber-Reinforced Polymer, Journal of Composites for Construction, 2005, Vol.9, No.3, pp.236-246.

The behaviour of six 1:2.5 scale reinforced concrete cantilever wall specimens having an aspect ratio 1.5, tested to failure and subsequently repaired and strengthened using fiber-reinforced-polymer (FRP) sheets is investigated. Specimens were first repaired by removing heavily cracked concrete., lap splicing the fractured steel bars by welding new short bars, placing new hoops and horizontal web reinforcement and finally casting non shrink high strength repair mortar. The specimens were then strengthened using FRP sheets and strips, with a view to increasing flexural as well as shear strength and ductility.

4.23) Hamid, A.A., El-Dakhakhni, W.W., Hakam, Z.H.R and Elgaaly, M., Behaviour of Composites Un-reinforced Masonry Fiber-Reinforced Polymer Wall Assemblages under In-Plane Loading, Journal of Composites for Construction, 2005, Vol.9, No.1, pp.73-83.

An experimental investigation was conducted to study the in-plane behaviour of face shell mortar bedded un-reinforced masonry (URM) wall assemblages retrofitted with fiber reinforced polymer (FRP) laminates. Forty two URM assemblages were tested under different stress conditions present in masonry shear and infill walls. Tests included prisms loaded in compression with different bed joints orientation, diagonal tension specimens, and specimens loaded under joint shear.

4.24) Dakhakhni, W.W.E., Drysdale, R.G and Khattab, M.M., Multilaminate Macromodel for Concrete Masonry: Formulation and Verification, Journal of Structural Engineering, 2005, Vol.132, No.12, pp.1984-1996.

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A macromodel was developed to predict the in-plane behaviour of concrete masonry. In this multilaminate model, the masonry assemblage is replaced by an equivalent material which consists of a homogenous medium intersected by two sets of planes of weakness along the head and bed joints.

4.25) Fouad M. Khalaf, New Test For Determination Of Masonry Tensile Bond Strength, Journal of Materials in Civil Engineering, 2005, Vol. 17, No. 6, December 1, pp725732

The bond strength between masonry units and mortar has been of considerable interest to researchers for some time. The flexural bond strength of masonry in particular is needed for the design of masonry walls subjected to horizontal forces applied normal to the face of the wall, such as wind forces. Researchers and standards have suggested different kinds of specimens and test procedures to determine the flexural bond strength. These include the test on wallettes (small walls), the bond wrench test, the Brench test, the direct tensile test, and the crossed couplet test. Each of these tests has its own drawbacks and problems. This paper presents a test method to determine the flexural bond strength, f fb, by bending. The test could be used for laboratory research to investigate the many factors affecting bond strength and also for deriving design values for masonry standards. The specimen is constructed from two brick units in a Z-shaped configuration, and three-point loading induces a flexural bond failure parallel to the bed joint. Three different types of clay brick, one calcium silicate brick, and three different types of mortar were used in the experimental program. The results derived show that the proposed new specimen and test procedure are capable of determining the flexural bond strength easily and accurately.

4.26) Carolin, A and Taljsten, B., Experimental Study of Strengthening for Increased shear Bearing Capacity, Journal of Composites for Construction, 2005, Vol.9, No.6, pp.488-496.

The need for structural rehabilitation of concrete structures all over the world is well known and a great amount of research is going on in this field. The use of carbon fiber reinforced polymer (CFRT) plate bonding has been shown to be a competitive method with regard to both structural performance and economic factors. This method consists of bonding a thin carbon fiber laminate or sheet to the surface of the structure to act as an outer reinforcement layer. However most research in this area has been undertaken to study flexural behaviour. This paper deals with shear strengthening of reinforced concrete members by use of CFRT. Test on rectangular beams 3.5 to 4.5 m long have been undertaken to study different parameters, such as fatigue, anchorage, and others. This strain field in shear spans of beams simultaneously subjected to shear and bending is also studied. The tests presented also contribute to the existing literature on tests of concrete members strengthened for increased shear capacity.

4.27) Prota, A, Marcari, G., Fabbrocino, G and Aldea, C., Experimental In-Plane Behaviour of Tuff Masonry Strengthened with Cementitious Matrix-Grid Composites, Journal of Composites for Construction, 2006, Vol.10, No.3, pp.223-233.

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Tuff building are a significant part of the Mediterranean area and are to be presented from a structural view point especially in seismic areas. Over the past few decades, the interest in strengthening of historical tuff masonry structures has led to developing specific and non-invasive architectural and engineering strategies. In the present paper, a comprehensive experimental program on tuff masonry panel is presented; the results are intended as a contribution to the knowledge of in-plane behaviour of tuff masonry strengthened with composite materials.

4.28) Almusallam, T.H and Al-Salloum, A., Behaviour of FRP Strengthened In-fill Walls under In-plane Seismic Loading, Journal of Composites for Construction, 2007, Vol.11, No.3, pp.308-318.

The present paper investigates the suitability and effectiveness of fiber-reinforced polymer (FRP) in strengthening and or repairing un-reinforced masonry infill walls in reinforced concrete frames which are subjected to in-plane seismic or cyclic loading. For this purpose, a detailed experimental program was conducted. Specimens geometry, test setup, instrumentation, and a loading procedure that simulates earthquake loadings are presented in a detailed fashion.

4.29) Wight, G.D., Kowalsky and Ingham, J.M., Shake Table Testing of Post-Tensioned Concrete Masonry Walls with Openings, Journal of Structural Engineering, 2007, Vol.133, No.11, pp.1551-1559.

The in-plane seismic response of post tensioned concrete masonry walls with openings is investigated by means of shake table testing. A test program was initiated to verify the seismic performance of a wall system for use in residential construction. Two single story in-plane wall tests were conducted initially to study the effect of door and window openings and wall corners.

4.30) Flint, G., Usmani, A., Lamont, S., Lane, B and Torero, J., Structural Response of Tall Buildings to Multiple Floor Fires, Journal of Structural Engineering, 2007, Vol.133, No.12, pp.1719-1732.

This paper reports on investigation of the effects of fire on long span truss floor systems in a tall building environment. The effect of the fire spread over multiple floors of a building are the focus of this research., especially where this may lead to progressive collapse. The results from an investigation of a two dimensional model of a multistory office building analysis are presented.

4.31) Moon, F.L., Yi, T., Leon, R.T and Kahn, L.F., Testing of a Full-Scale Un-reinforced Masonry Building Following Seismic Strengthening, Journal of Structural Engineering, 2007, Vol.133, No.9, pp.1215-1226.

To investigate the effectiveness of several seismic strengthening techniques, a full scale un-reinforced masonry (URM) structure was subjected to slowly applied lateral load reversals after the application of fiber reinforced plastic overlays, near surface mounted rods, and vertical post tensioning.

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4.31) Popehn, J.R.B., Schultz, A.E and Drake, C.R., Behaviour of Slender, Post-tensioned Masonry Walls under Transverse Loading, Journal of Structural Engineering, 2007, Vol.133, No.11, pp.1541-1550.

A conceptual model of the response of slender, post tensioned masonry walls to uniformly distributed, transverse loading is introduced and vertical through an experimental program. To validate the model, 12 simply supported 3.54 m (11.6 ft) tall walls with 810x100 mm cross-section were tested under monolithically increasing transverse loads. Six walls were built using cored clay brick and the remaining six using hallow concrete block. The walls were post tensioned using threaded steel bars with six walls featuring unrestrained tendons, while the other six had restrained and three magnitudes of effective pre-stress were investigated. Initial responses to transverse load was linear, but cracking was observed over a broad range of loading. The response of the wall specimens is traced through crack propagation, hinge formation, and development of the plastic section.

4.32) M. Harajli, H. ElKhatib and J. Tomas San-Jose, Static and cyclic out-of-plane response of masonry walls Strengthened using textile-mortar system, Journal of Materials in Civil Engineering, 2010, Vol. 22, No. 11, November1, pp1171-1180

The work presented in this paper is a part of a comprehensive research project aimed at developing and testing a system for strengthening historical buildings. The system is composed of a combination of textile mesh and mortar. Representative wall specimens were tested for their out-of-plane flexural behavior under static and cyclic loadings. The parameters investigated include the types of masonry wall (concrete block, sandstone, and brick), mortar (natural lime and cement-based), and textile (bitumen coated E-glass, basalt, or coated basalt fibers). Companion specimens, strengthened using a steel wire mesh, were also tested for comparison. All textile-mortar reinforced masonry (TRM) wall specimens failed in a combination of transverse detachment of the textile-mortar matrix due to the transverse displacement of the blocks relative to each other, and combined transverse shear-tension fracturing of the textile fibers. Regardless of the mode of failure, the TRM specimens developed a substantial increase in their out-of-plane load and displacement capacities under static loading, and low stiffness and strength degradation, and considerable displacement capacities under cyclic loading. The wire mesh-mortar reinforced masonry specimens developed the highest load capacity but were the least ductile when compared to the TRM specimens.

4.33) Francesca da Porto, Giovanni Guidi, Enrico Garbin and Claudio Modena, In-plane behavior of clay masonry walls: experimental Testing and finite-element modeling, Journal of Structural Engineering, 2010, Vol. 136, No. 11, November1, .pp13791392

Extensive experimental research aimed at defining the in-plane cyclic behavior of three types of load-bearing masonry walls, assembled with perforated clay units, and various types of head and bed joints was carried out. Experimental behavior was modeled with four types of nonlinear finite-element models. Both macromodeling and micromodeling strategies, implementing either isotropic or orthotropic material laws, were adopted. Two simplified criteria were proposed for calibrating the models, one for defining orthotropic properties starting from perforated unit geometry and the

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other for defining expanded unit and interface element properties in micromodels. The procedures adopted for model calibration established the reliability of various modeling strategies. Results allow some conclusions to be drawn about the reliability of diagonal compression tests for large unit masonry, the stress distribution and different behaviors of masonry made with different head and bed joints, and the influence of unit strength on the in-plane behavior of masonry.

4.34) Marco Di Ludovico, Claudio DAmbra, Andrea Prota and Gaetano Manfredi, FRP Confinement Of Tuff And Clay Brick Columns:Experimental Study And Assessment Of Analytical Models, Journal of Composites for Construction, 2010, Vol. 14, No. 5, October 1, pp583596

In recent years, fiber-reinforced polymer (FRP) wrapping effectiveness has been clearly confirmed especially with reference to concrete structures. Despite evident advantages of FRP based confinement on members subjected to compressive overloads due to static or seismic actions, the use of such technique in the field of masonry has not been fully explored. Thus, to assess the potential of confinement of masonry columns, the present paper shows the results of an experimental program dealing with 18 square cross sections (listed faced tuff or clay brick) masonry scaled columns subjected to uniaxial compression load. In particular, three different confinement solutions have been experimentally analyzed in order to evaluate and compare the effectiveness of uniaxial glass FRP, carbon FRP, and basalt FRP laminates wrapping. The main experimental outcomes are presented and discussed in the paper considering mechanical behavior of specimens, axial stress-axial strain relationships, and effective strains at failure on the reinforcement. Test results have showed that the investigated confining systems are able to provide significant gains both in terms of compressive strength and ductility of masonry columns. Results of the presented experimental activity along with data available in the literature have been finally used to assess the reliability of the main existing analytical models; refined equations have been then proposed to minimize the scattering between theoretical predictions and experimental available data.

4.35) Daniel V. Oliveira, Ismael Basilio and Paulo B. Loureno, Experimental Behavior Of Frp Strengthened Masonry Arches, Journal of Composites for Construction, 2010, Vol. 14, No. 3, June1, pp312322

This paper deals with the experimental behavior of solid clay brick masonry arches strengthened with glass fiber-reinforced polymer composites. Twelve half-scaled segmental masonry arches subjected to a load applied at the quarter span were tested under displacement control up to failure. The arches were built using handmade low strength bricks and a commercial lime-based mortar, trying to mimic ancient structures. Besides reference unreinforced arches, five different strengthening arrangements, including the use of spike anchors, were studied. The experimental results provide significant information for validation of advanced numerical models and analytical tools and for code drafting. The experimental results also show that (1) only continuous strengthening strategies are able to prevent typical local failure mechanisms of unreinforced arches; (2) strengthening at the intrados is the most effective option to increase strength; and (3) strengthening applied at the extrados provides the higher deformation capacity prior to failure, endowing arches with considerable ductility behavior.

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4.36) Vladimir G. Haach, Graa Vasconcelos and Paulo B. Loureno, Experimental analysis of reinforced concrete block Masonry walls subjected to in-plane cyclic loading, Journal of Structural Engineering, 2010, Vol. 136, No. 4, April 1,.pp452462

An innovative system for reinforced concrete masonry walls based on the combination of vertical and horizontal trussed reinforcement is proposed. The mechanical characterization of the seismic behavior of such reinforced masonry walls is based on static cyclic tests carried out on panels with appropriate geometry. The influence of the factors influencing the in-plane cyclic behavior of concrete masonry walls, such as the horizontal reinforcement, precompression, and masonry bond pattern, is discussed. The results are analyzed in terms of failure modes and force versus displacement diagrams, from which the seismic performance is assessed based on the ductility and energy capacity dissipation. The results stressed that the increase on the precompression level leads to a stiffer and more brittle lateral behavior of the masonry walls. The presence of horizontal reinforcement ensures better control and better distribution of cracking, even if only a marginal increase of lateral strength was found in the particular testing program.

4.37) Khaled Galal and Munir Alp Enginsal, Flexural Behavior Of Gfrp-Reinforced Concrete Masonry Beams, Journal of Composites for Construction, 2011, Vol. 15, No. 1, February 1, pp2131

An experimental and analytical study is conducted in order to investigate the flexural behavior of masonry beams that are internally reinforced using glass fiber-reinforced polymers _GFRP_ rebars. Seven reinforced masonry beams with 4.0- and 2.4-m spans were tested under four-point bending setup. The beams were loaded monotonically up to failure. One had two courses of hollow concrete masonry units and the remaining six beams had three courses. Two masonry beams were reinforced using conventional steel rebars and were considered as the control specimens. The remaining five beams were internally reinforced using GFRP rods with different reinforcement ratios. Beams were detailed to have sufficient shear reinforcement such that they do not fail in shear. Flexural capacity, deformation, curvature, and strains of the tested GFRP-reinforced and steel-reinforced masonry beams were compared and discussed. Using the acquired data from the experimental and analytical studies, effectiveness of GFRP rods as internal reinforcement for concrete masonry beams is demonstrated.

4.38) N. Augenti, F. Parisi, A. Prota and G. Manfredi, In-Plane Lateral Response Of A Full-Scale Masonry Sub Assemblage With And Without An Inorganic Matrix-Grid Strengthening System, Journal of Composites for Construction, 2011, Vol. 15, No. 4, August 1, pp578590

A full-scale unreinforced masonry (URM) wall with an opening was tested under in-plane lateral loading. The wall was first subjected to monotonically increasing displacements until a moderate damage level was reached. The damaged specimen was then cyclically tested up to almost the same maximum drift attained during the monotonic test to investigate the effects of previous damage on its nonlinear response. Finally, the masonry wall was repaired with inorganic matrix-grid (IMG) composites and subjected to a cyclic displacement controlled test up to a near-collapse state. Most

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of the observed damage developed in the spandrel panel affecting both lateral resistance and strength degradation. Rocking of piers governed lateral stiffness and hysteretic response, which was characterized by low residual displacements and re-centering behavior. The comparison between the experimental force-displacement curves demonstrated that the IMG strengthening system was able to provide energy dissipation capacity to the spandrel panel, restoring load-bearing capacity of the as-built wall, and delaying strength degradation that was indeed observed at larger displacements. Bilinear idealizations of force-displacement curves allowed the identification of displacement ductility, global over strength, and strength reduction factor of the tested wall systems.

5.0 ANALYSIS AND DESIGN

5.1) Vermeltfroot, A.T., Groot, W.P., Wijen, E., Strains in Re-pointed Masonry Under Compression: Preliminary Investigation Using ESPI, Tech. Report, Eindhoven University of Technology, The Netherlands, 1985, pp.138-147.

This paper reports the results of preliminary investigations on the mechanical behaviour under compressive load of two combinations of re-pointing and bedding mortars used in combination with two types of bricks. The mechanical behaviour is studied using ESPI (Electronic Speckle Pattern Inter-ferometry ). Special attention is paid to stress concentrations due to the mechanical incompatibility of the bedding and pointing mortar. In particular, hard re-pointing material applied on :soft bedding mortar shows a high degree of mechanical incompatibility.

5.2 Cavaiheiro, O.P., Pozzobon, A.N and Santos, M.D.F., Diagonal Tensile and Compressive Strength of Hollow Clay and Concrete Block Specimens, Tech. Report, Federal University of Santa maria, Brazil, 1987, pp.157-163.

The paper presents some experimental results of diagonal tensile strength of hollow clay and concrete blocks specimens with filled and unfilled head (vertical) joints as well as results of compressive strength of blocks and stack bounded prisms of two and three units for both types of block. Three types of mortar mixes (low, medium and high) were used in the investigation. It appears that the diagonal tensile strength is significantly lower for specimen with unfilled head joints compared to specimen with filled head joints: and the ratio of compressive strength of the block unit is considerably higher for concrete block than for clay block.

5.3) Guha, A.L., An Isotropic Elasto Plastic Model for Masonry Wall Subjected to Biaxial In-plane Loading, Tech. Report, Bengal Eng College., Howrah., India., 1987, pp.171-186.

A material model suitable for finite element analysis subjected to in-plane loading is presented. To account for the directional strength properties at failure a generalized anisotropic quadratic failure criterion has been used to model the non-linear behaviour of masonry. The magnitude of the interaction term is restrained in such a way that the shape of the failure surface is ellipsoidal. Sensitivity and analysis has been carried out to select the type of test results to be used for the determination of the interaction strength parameter. The failure criterion agrees well with the experimental failure envelope for uni-axial and biaxial compressive loading. Smeared crack approach with

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fixed crack angle is adopted for modeling of the cracking behaviour of masonry. Maximum stress criterion for anisotropic material has been used for initiation and propagation of cracks. Tensile strain softening is employed for gradual release of tensile stress after cracking. Closing and reopening of cracks are allowed in this model following the secant path.The finite element method of analysis incorporating the proposed material model has been employed to study the in plane behaviour of the masonry shear walls to demonstrate the suitability of the material model, structural idealization and numerical techniques by comparing the computed behaviour with the experimental results. The predicted behaviour is in good agreement with the experimental results.

5.4) Neto, J.A.D.N., Correa, M.R.S and Ramalho, M.A Analysis of Torsion Effects on the Bracing Systems of Masonry Buildings, Tech. Report, USP-University of Sao Paulo, Brazil, 1990, pp.193-201.

The brazing system of a masonry building is usually designed as a plane association if isolated walls. Although simple to use this model fails to allow for the simulation of important aspects of bracing system behaviour, such as those related to the overall torsion of the building. The proposed numerical modeling using beam elements allow for a three dimensional consideration of the structural system, including bending and shear effects on displacements, as well as the interaction of bonded walls. A numerical example of a multistory building loaded horizontally is discussed. Bending moments and shear force distribution are shown, including the displacements on each storey level. The analysis is developed based on the linear elastic behaviour of the masonry, although the proposed modeling can easily be extended to the non linear behaviour of the material.

5.5) Weerapun Sriboonlue and John H. Matthys, Torsional Behavior Of Reinforced Brick Beams, Journal of Structural Engineering, 1990, Vol. 116, No. 6, pp1626-1647.

Laboratory tests of 21 reinforced brick masonry beams under pure torsion are described. Also, an ultimate torsional strength theory for brick masonry beams subjected to pure torsion is developed. The study described has been undertaken to obtain information about the behavior of reinforced brick masonry beams subjected to pure torsion. Beam specimens are rectangular in cross section and composed of two wythes of brick facings with a grout core reinforced with varying percentages of steel. Three types of brick are used with type S Portland cement lime mortar to provide different ranges of the ultimate compressive strength of masonry. Specimens are grouped into four series of tests in which the reinforcement patterns were different between each series. An ultimate strength theory is developed based on the failure mechanism using elastic bending theory and transformation of the cross section. Although comparison of the predicted ultimate strength theory of beams under pure torsion to actual beam test values show appreciable scatter, the results are predictable to an acceptable degree of confidence.

5.6) Capozucca, R., Analysis of Pre-stressed Brickwork Masonry Column under Shear Force, Tech. Report, I.S.T.C. University of Ancona, Italy, 1991, pp. 215-227.

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In seismic areas the behaviour of masonry buildings is greatly influenced by the presence of slender elements, like brick work masonry columns, which reduce the bearing capacity to shear force. Masonry buildings, in fact as typical shear wall structures linked by floors, may even resist to elevated horizontal seismic actions. The weakness of masonry column is often the cause collapse under horizontal force. The stability of a brickwork masonry column is due to the vertical load, but during the seismic action an elevated value of load may cause an increase of bending as consequence of P-d effect. In seismic area the pre-stressed technique is suitable and the bending capacity column is increased. In this paper, the theoretical behaviour of pre-stressed brickwork masonry columns was analyzed by means of resistant bending moment-normal force diagrams for reinforced section. Shear resistance and decreasing of resistance due to P-d effect were also considered. Results obtained by experimental tests on a full-scale brickwork pre-stressed column were shown.

5.7) Anon., Standard Specification and Analysis for Masonry with Rat-Trap Bond, Proceedings, South Zone Training Centre, Chennai, India, 1992, pp.1-7.

Specifications for brick work in Rat-Trap for masonry structures and its Labour and material analysis of cost-effective construction techniques have been discussed in this report.

5.8) Andreaus, U., Failure Criteria for Masonry Panels under In-plane Loading, Journal of Structural Engineering, 1996, Vol.122, No.1, pp.37-46.

Failure of masonry panels under in-plane loading can be attributed to three simple modes: slipping of mortar joints, cracking of clay bricks and splitting of mortar joints, and middle plane spalling. In this paper a suitable strength criterion is connected to each collapse mode. In more detail, a frictional law is associated with the slipping, which accounts for the shear strength depending nonlinearly on normal stress ( modified Mohr-coulomb criterion of intrinsic curve). Splitting can be expected by the maximum tensile strain criterion (Saint venant), orthotropic non symmetric elasticity being assumed for the material. Eventually panels exhibit spalling when the maximum compressive stress (Navier criterion) is attained under biaxial loading, Strength parameters are then identified on the basis of experimental results and a comparison with the reliable criteria found in the literature is carried out. The validity of the proposed failure criteria to predict the experimental failure modes in a non-dimensional stress space, normalized with respect to the normal stress, has been tested in a qualitative manner for the three fundamental failure modes. A quantitative comparison between experimental and analytical results has been carried out for the cases where significant scatters are concerned. The proposed failure criteria seem to be in good agreement with experimental results, within the limits of: small size panels, single withes, solid units, regular mortar joints, and in-plane loads. Further, these criteria can be used together with a suitable two dimensional finite element model, and then directly used to carry out the limit analysis of masonry walls, modeled by a discrete number of panels of finite size. The potential application of the proposed criteria to actual cases is also illustrated. In fact, a specific example is worked out to show how to apply these criteria to predict the failure load failure mode of a particular masonry panel.

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5.9) S. Briccoli Bati, G. Ranocchiai and L. Rovero, Suitability of micromechanical model for elastic analysis Of masonry, Journal of Engineering Mechanics, 1999, Vol. 125, No. 8, August, pp 09220929

A micromechanical model is proposed for determining the overall linear elastic mechanical properties of simple-texture brick masonry. The model, originally developed for long-fiber composites, relies on the exact solution due to Eshelby and describes brickwork as a mortar matrix with insertions of elliptical cylindershaped bricks. Macroscopic elastic constants are derived from the mechanical properties of the constituent materials and phase volume ratios. Conformity of the suggested model to real brickwork behavior has been verified by performing uniaxial compression tests on masonry panels composed of fired bricks and mud mortar. Composite masonry panels of varying phase percentages were then constructed and tested by replacing several of the fired bricks with mud bricks. Comparison of experimental results with theoretical predictions demonstrates that the model is suitable even in the presence of strongly differentiated phases, and is moreover able to predict different behavior as a function of phase concentration. The model fits experimental results more closely than the micromechanical models previously reported in the literature.

5.10) Vafai, A., Hamadi, M and Ahmadi, G., Numerical Modeling of MDOF Structures with Sliding Supports Using Rigid-Plastic Link, Earthquake Engineering and Structural Dynamics, 2001, Vol.30, pp.27-42.

In this paper the responses of multi-degree-of-freedom (MDOF) structures on sliding supports subjected to harmonic or random base motions are investigated. Modeling of the friction force under the foundation raft is accomplished by using a fractious rigid link which has a rigid-perfectly plastic material. This will results in identical equations of motions for the sliding structure, both in the sliding and non- sliding (stick) phase which greatly simplifies the implementation of the method in to a numerical algorithm. In this model the phase transition times are determined with high accuracy. This has two advantages: first, it prevents the so-called high frequency oscillation of the relative velocity at the end of the sliding phase and second, the time steps can be selected so that each falls exactly within one phase of motion. In this case, the stiffness matrix of the structure remains constant throughout each phase and thus any method for solving the nonlinear differential equations of motion (e.g : Network method ) can be used without iteration. The proposed method, besides its simplicity, is numerically very efficient and considerably reduces the required analysis time compared with most of the other methods.

5.11) Zhang, X., Singh, S.S., Bull, D.K and Cooke, N., Out-of-plane Performance of Reinforced Masonry Walls with Openings, Journal of structural engineering, 2001, Vol.127, No.1, pp.51-57.

The Out-Of-Plane performance of partially grouted, reinforced concrete masonry walls subjected to simulated seismic loading is investigated. The three full scale walls, with and without openings, were constructed from 190 mm thick concrete blocks and were 9.00 m long and 2.40 m with two 2.50 m long return wa