15 th International Conference on Experimental Mechanics ICEM15 1 PAPER REF: 3023 EXPERIMENTAL EVALUATION OF THE SHEAR STRENGTH OF MASONRY WALLS Jelena Milosevic 1 (*) , António Sousa Gago 2 , Rita Bento 3 , Mário Lopes 4 1, 2, 3, 4 ICIST, IST; Technical University of Lisbon, Portugal (*) Email: jelena@civil.ist.utl.pt ABSTRACT In this work diagonal compression tests and triplet tests on rubble stone masonry specimens are described and the results obtained presented. For the tests carried out different dimensions of masonry specimens were adopted and two different types of mortar were used in the specimen’s construction, namely hydraulic and air lime mortar. The general objectives of the work presented herein are to determine: i) initial shear strength (cohesion) of masonry via diagonal compression test and ii) initial shear strength, or cohesion and coefficient of friction by triplet test. This study was developed within the scope of the national research project SEVERES (www.severes.org). Keywords: masonry, diagonal compression tests, triplet tests, shear strength, cohesion INTRODUCTION Old masonry buildings are integral and very important parts in most of the European cities. These buildings are still being used, for housing and services, as their main function. In Lisbon and other Mediterranean cities, old masonry buildings with rubble stone masonry walls are generally exposed to a very high seismic risk due to high probability of earthquake occurrence. In urban areas, the percentage of these buildings, their heritage value and the increasing concern about people’s safety led to several studies aiming the structural characterization of old masonry buildings. In order to support simulation of building structural behaviour, for any numerical analysis, it is important to know the mechanical characteristics of the materials. However, until now, there are not many studies where values for shear strength parameters of old masonry buildings can be found, which otherwise is a very relevant parameter for the evaluation of seismic behavior of masonry buildings. The main goal of the project is to characterize the seismic behavior of traditional rubble stone masonry walls, including experimental tests for characterization of the shear strength of rubble stone masonry. These tests involves of diagonal compression and triplet tests (described in this paper) and cyclic shear test. To characterize the initial shear strength (cohesion), diagonal compression tests were performed on four big rubble masonry specimens, two with hydraulic (W1 and W4) and two with air lime mortar (W2 and W3), with dimension 120  120  70cm. The test setup and procedure for diagonal compression test followed the ASTM E519-02 standard [ASTM, 2002] and what is suggested in recent research works [Corradi, 2003, Brignola, 2008]. Other nine wall prototypes (60  40  40cm) were subjected to triplet tests following the major lines of EN 1052-3 standard [BS EN, 2002] and of the other works [Prota, 2006, Oliveira, 2002], since they oriented to brick masonry. Until now triplet tests on rubble stone masonry specimens are not describe in any standard or performed in other experimental campaign. It