Post-earthquake Damage Simulation of Two Colonial Unreinforced Clay Brick Masonry Buildings Using the Equivalent Frame Approach

In New World colonial countries and territories such as Australia, New Zealand, and the West Coast of North America, the predominant form of unreinforced masonry (URM) construction is relatively modest one or two storey buildings composed of clay brick masonry. While the equivalent frame (EF) approach for modelling the in-plane seismic response of URM buildings is gaining popularity, particularly in Mediterranean countries, the procedure is currently relatively unknown elsewhere and the validity of the procedure when applied to simple and prevalent New World clay brick URM construction has not yet been demonstrated in a meaningful way. To address this deficiency and provide a novel evidence base for use of the procedure by the professional structural engineering community, modelling of the seismic response of two unreinforced clay brick masonry buildings that were damaged during the 2010/2011 Canterbury earthquake sequence is reported. Static and dynamic nonlinear analyses were undertaken by applying the equivalent frame (EF) approach, and time-history records attained during the Canterbury earthquake sequence were used to conduct dynamic analyses and facilitate direct comparison to observed building damage. The effect of diaphragm stiffness on the global response of the two case-study buildings was also studied. It is shown that use of the EF method enabled prediction of the seismic response of the two case-study clay brick URM buildings with a high level of accuracy.