Seismic Response of Buildings with Flexible Floors

Abstract

It is shown that for long narrow buildings with identical frames and identical walls, the modes that involve in-plane floor deformations are not excited by earthquake ground motion. Therefore, the floors in such buildings can be treated as rigid in their own plane in earthquake analysis without introducing an additional approximation. However, this result presupposes the acceptability of the lumping of masses of the building at the floor-frame intersections. In addition, the result does not necessarily hold for other types of excitation.