Vertical acceleration demands on nonstructural components in buildings

Abstract

This paper addresses the statistical evaluation of vertical peak floor acceleration (PFAv) demands on elastic multistory buildings using recorded ground motions. Typical buildings are considered to be relatively flexible in the horizontal (lateral) direction and relatively rigid in the vertical (longitudinal) direction. The vast majority of studies conducted on the quantification of component acceleration demands have considered the flexibility of the nonstructural component (NSC) and its supporting structure primarily in the lateral direction. Studies on the evaluation of vertical component acceleration demands throughout a building are scarce and different opinions exist on the relevance of vertical accelerations in buildings. This paper focuses on the quantification of PFAv, which implies that NSCs are assumed to be rigid in the vertical direction. Only rigid NSCs located close to columns of moment-resisting frames are considered. Thus, the influence of vertical floor vibrations and their dependence on the properties of the floor system is not addressed. The results demonstrate that the amplification of vertical ground acceleration demands throughout a building depends on the vertical stiffness of the load bearing structure, and hence, the common assumption of rigid-body responses in the vertical direction is highly questionable.