BAKHSHI, ALI1; SOLEIMANZADEH, AMIR2; YEKRANHNIA, MOHAMMAD3

1) Associate Professor, Department of Civil Engineering, Sharif University of Technology, Tehran 1458889694, Iran, bakhshi@sharif.edu

2) M.Sc Graduate, Dept. of Civil Eng., Sharif University of Technology, Tehran 1458889694, Iran, amir soleimanzadeh@ yahoo.com

3) PhD Candidate, Dept. of Civil Eng., Sharif University of Technology, Tehran 1458889694, Iran, yekrangnia@mehr.sharif.ir

Although Unreinforced Masonry (URM) is one of the most vulnerable structural types against earthquakes, they constitute the most abundant building systems throughout the world. Considering inherent complexity in URM walls seismic performance and their rather unknown response, there is a need in understanding their true nature. Speaking of URM walls response direction, there are two district in-plane (IP) and Out-of-plane (OP) modes on which many researches have been made. However, since the multidirectional nature of any seismic actions, these modes experience interaction and this phenomenon results in weakening in each mode.

In this paper, IP-OP interaction of several URM walls having various aspect ratios is studies by FEM analyses making use of micro modelling approach. Sensitivity of parameters including compressive strength of brick and mortar and surcharges are also taken into account. The results indicate that great dependency of OP strength to IP damages which should be considered in relations for determination of OP strength.

Keywords: URM walls, IP-OP interaction. FEM analysis, Micro modelling