Facade isolation in seismic design of tall buildings

Abstract

Vulnerability of non-structural components in buildings subjected to earthquake incidents has caused human and financial losses in recent years. A part of such losses is related to the facade of buildings. In typical structures, facade assembly is directly connected to the structural system and is subjected to large lateral deformation during seismic actions. To reduce the level of earthquake-induced damage to the facade and the main structural system, the method of Facade Isolation (FI) is introduced. In this approach, facade frame is isolated from the main structural system using high damping flexible isolators. Numerical studies on the role of FI in a typical 15-story building with different facade configurations have been carried out in this work. According to the results of this study during seismic actions lateral drift response of facade frame in the isolated building is reduced to about 1/3 of that in the non-isolated one. This has happened while lateral force and drift ratio for the main structural system has also been reduced. In this approach facade frame serves as an integrated part of the structural system; to not only improve seismic performances of the building but to diminish the possibility of breakage and falloff for cladding materials during seismic actions.