COLLAPSE MODES OF CONFINED MASONRY BUILDINGS IN THE WENCHUAN EARTHQUAKE

Confined masonry structures are a widely applied structural system in China. During the Wenchuan Earthquake numerous confined masonry buildings collapsed, while many others suffered damage. This study proposes simple hand calculations for quantifying the tearing failure of diaphragms, the tensile failure of tie-columns and the soft-storey failure of masonry buildings. The results indicate very good agreement with the recorded destruction of buildings in the Wenchuan Earthquake. For those buildings that survived the earthquake, strength rather than ductility protected the confined masonry from collapse or serious damage.