| nreinforced masonry (URM) infill walls are widely used in structures in North America. In several “pre-code” hospital buildings constructed before the 1970s, terra cotta masonry blocks have been used extensively. Although unreinforced terra cotta infill walls play a structural role, interior partitions are generally considered as non-structural components (NSCs) and their stiffness effects on the structure are often ignored in seismic analysis and design, while their weight/mass is included as uniformly distributed load/inertia. Terra cotta infill walls interact with their bounding frame during earthquakes and increase the lateral stiffness and strength of the structure, which in turn influences the dynamic response of the building. Of course, as they get damaged in strong earthquakes, their stiffness is degrading and they either become locally detached from the frame or they simply collapse. In situ vibration measurements and observations of past earthquake-induced damage clearly demonstrate the necessity of considering the effect of infill walls on structural response, particularly for post-critical buildings such as hospitals which have to remain functional after severe design-level seismic shaking.;To illustrate the structural contribution of infill terra cotta walls, two eleven-storey buildings have been selected which are two wings (Blocks ;Finally, the lateral stiffness of the rehabilitated block... |
