15 th International Brick and Block Masonry Conference Florianópolis – Brazil – 2012 NUMERICAL SIMULATION OF CONCRETE BLOCK MASONRY UNDER COMPRESSION Mohamad, Gihad 1 ; Lourenço, Paulo Brandão 2 ; Roman, Humberto Ramos 3 ; Rizzatti, Eduardo 1 ; Sartori, Tatiane 4 1 Dr. Federal University of Santa Maria, Civil Engineering Department, gihad.civil@gmail.com ; edu_rizzatti@yahoo.com.br ; 2 PhD, Professor, University of Minho, Civil Engineering Department, pbl@civil.uminho.pt 3 PhD, Professor, Federal University of Santa Catarina, Civil Engineering Department, humberto@ecv.ufsc.br 4 Federal University of Santa Maria, Master Science Student on Production Engineering Department, tatianesartori@yahoo.com.br The main goal of this work is evaluate numerical model to reproduce the compression test of concrete block prisms, through a constitutive model of materials using the theory of plasticity and compare its results with experimental tests to preview the stress, strain and failure mode of the masonry. The post peak behavior of the material under tensile followed an exponential law and, under compression, a parabolic criterion was specified for the ascendant and descendent parts of the stress diagram and the hardening parameter. The mortar was connected to the block by the interface, for which the discrete model was employed, where the cracking occurred when the normal stress exceeded the tensile strength of the material. Keywords: Non-linear Behavior, Concrete Block Masonry, Interface Elements; INTRODUCTION The main deformation modes of an interface are related to kinematic phenomena, such as: localized deformation, sliding, opening and dilatance. Therefore, studies of failure mechanisms of masonry under loading are required, considering a cohesive interface (before the strength peak) and a single friction model (post peak). Martins (2001) carried out shear tests on hollow concrete block prisms with two levels of strength for the block and three for the bedding mortar. The concrete block prisms have a space between the middle blocks so that, during the tests, the blocks could slide and cause shearing at the contact between the mortar and the block. Figure 1 shows the prisms and the set up of the tests. Figure 1: Block prisms for the shear tests with and without lateral by Martins (2001).