DERAKHSHAN, HOSSEIN1; GRIFFITH, MICHAEL2; INGHAM, JASON3

1) Post-Doctoral Research Fellow, School of Civil, Environmental, and Mining Engineering, The University of Adelaide, hossein.derakhshan@adelaide.edu.au

2) Professor, School of Civil, Environmental, and Mining Engineering, The University of Adelaide, michael.griffith@adelaide

A simplified numerical model was used to investigate the out-of-plane seismic behaviour of unreinforced masonry (URM) walls. The URM walls were assumed to span vertically between the ground and a flexible diaphragm or between two flexible diaphragms and to have developed a horizontal crack above the wall mid-height. Three degrees of freedom were used to accommodate the wall displacement at the lower diaphragm, at the crack height, and at the top diaphragm connection, and the wall dynamic stability when subjected to different ground motion records was studied. The equations of dynamic motion were obtained using principles of rocking mechanics of rigid bodies and the formulae were next modified to include semi-rigid wall behaviour. The suitability of the model for calculation of the maximum wall displacement response was verified using existing pool of experimental data.

Keywords: Flexible diaphragms, stability, unreinforced masonry wall, out-of-plane, earthquake