Towards displacement-based seismic design of modern unreinforced masonry structures

Unreinforced masonry (URM) structures are known to be rather vulnerable to seismic loading. Modern URM buildings with reinforced concrete (RC) slabs might, however, have an acceptable seismic performance for regions of low to moderate seismicity. In particular in countries of moderate seismicity it is often difficult to demonstrate the seismic safety of modern URM buildings by means of force-based design methods. Displacement-based design methods are known to lead to more realistic and less conservative results, opening up hence new opportunities for the use of structural masonry. An effective implementation of displacement-based design approaches requires reliable estimates of the structure’s force and displacement capacity. This paper contributes to this endeavour by taking a fresh look at the drift capacity of URM walls with hollow clay bricks and mortar joints of normal thickness. It discusses in particular the influence of the size of the test unit and the applied loading history and loading velocity on the drift capacities of URM walls.