Vertical acceleration demands on column lines of steel moment-resisting frames

In this paper, vertical peak floor acceleration (PFA(v)) demands on elastic multistory buildings are statistically evaluated using recorded ground motions. These demands are applicable to the assessment of nonstructural components that are rigid in the vertical direction and located at column lines or next to columns. Hence, PFA(v) demands of the floor system away from column lines and their effects on nonstructural components are not addressed. This study is motivated by the questionable general assumption that typical buildings are considered to be relatively flexible in the horizontal (lateral) direction but relatively rigid in the vertical (longitudinal) direction. Consequently, only few papers address the evaluation of vertical component acceleration demands throughout a building, and there is no consensus on the relevance of vertical accelerations in buildings. The results presented in this study show that the vertical ground acceleration demands are amplified throughout the column line of a steel frame structure. This amplification is in many cases significant, depending on the vertical stiffness of the load-bearing system, damping ratio, and the location of the nonstructural component in the building. From these outcomes it can be concluded that the perception of a rigid-body response of the column lines in the vertical direction is highly questionable, and further research on this topic is required. Copyright (c) 2016 John Wiley & Sons, Ltd.