A macro-scale truss model for nonlinear analysis of masonry walls

In this research, a truss model is introduced to simulate the in-plane behavior of masonry walls in different failure modes. In the proposed model, the structural members are divided into smaller two-dimensional panels and then a truss system is used to model each panel. How to determine the geometry, dimensions and behavioral model of these truss elements are introduced according to the behavioral mechanism and failure modes of the masonry wall. The dimensions of the truss members are determined in such a way that the stiffness of the truss model is the same as the stiffness of the initial panel, under different loads. In this regard, the computational method introduced by Aghababaei is used. The elasto-plastic-fracture model developed at the University of Tokyo is used for compressive behavior of elements. Barimani et al. evaluated and verified the accuracy of this model. Also for tensile and post cracking behavior of masonry, the tension softening model of Maekawa et al. is used. In order to apply the effects of cracking on the compressive behavior of the diagonal elements, a softening model dependent on the crack width is introduced. The idea used is generally based on the smeared crack approach. In this model, after identifying the pair of each diagonal element and as soon as a crack occurs in one diagonal element, the behavior of the other diagonal element is modified by multiplying the force values ​​in a proposed function. Then, the results of the analysis are evaluated based on ASCE41 code in different failure modes. Also, for verification, two I-shaped masonry walls, three masonry walls with rectangular cross-section and an arched walls are numerically analyzed using the proposed model and the results of numerical and experimental tests are compared. The results show that the proposed model, while simple, has a good ability to estimate the nonlinear behavior of masonry wall.