POST CRACKING BEHAVIOUR OF MASONRY SHEAR WALLS

Abstract

A mason r" wall panel is the basic element in the load bearing cons-truction which resists the inplane lateral forces produced by wind or earth-quake along with the gravity load. The behaviour of brick masonry shear walls has been investigated over many years but most of the earlier studies were limited tc firsi. cracking load only. Their strength is usually defined in terms of the average shear and normal stresses on the bed joints, regard-less of the t: sting techniques adopted. No rational method is available to predict the behaviour of shear wall for various types of edge support and openings Df different sizes and locations, upto failure. In the present study an incremental iterative non linear finite element formulation has been developed which takes into account the non linearity caused due tc progressive cracking alone of the material. Material is assumed to fail under any one of the three failure criteria adopted here i .e . princi-pal tension failure criterion, shear failure criterion and biaxial tension compression failure criterion. A suitable computer program NLAM has been developed to facilitate computer aided analysis of masonry shear walls. For experimental investigation of the behaviour of masonry shear walls, a half brick thick masonry wall panel without flange has been chosen as the model . Elastic properties and strength characteristics of the masonry and constituent material have been determined experimentally using suitable control spec imens . Racking test has been performed on two such model wall panels unto failure load. Deflection measurement have been taken at selected poirts . Characteristic stepped diagonal failure has been observed . Theoretical analysis of the panels tested have been done using computer programme developed in the study and the appropriate masonry properties determined ex:;.erimentally . It has been found that deflection characteristics