ESTIMATING ROOF-LEVEL ACCELERATION SPECTRA FOR SINGLE STOREY BUILDINGS

Abstract

The performance of both structural and non-structural elements should clearly be considered when assessing the seismic safety and performance of a building. The perfor- mance of non-structural elements tends to be dependent on storey drift demands, acceleration demands or both. However, a simplified reliable means of estimating the acceleration de- mands on non-structural elements appears to be lacking, particularly for non-structural ele- ments characterized by an elastic damping ratio that is not equal to 5% critical damping. As such, this paper presents a simplified means of predicting roof level acceleration spectra for single storey buildings. Such spectra should be useful in assessing the response of parapets or relatively lightweight appendages such as antennae, ceilings or mechanical services attached to the roof of single-storey buildings. As the procedure is formulated using concepts of me- chanics and dynamics it is applicable to single-storey buildings that respond either in the li- near or non-linear range, and is able to be adjusted for a wide range of elastic damping values. To gauge the performance of the procedure, spectra obtained from the approach are compared to those obtained from non-linear time-history analyses of a single storey building subject to ten ground motions scaled to various levels of intensity. The results demonstrate that the simplified approach for estimating roof level acceleration spectra works well and the possibility of extending it to multi-storey buildings should be explored as part of future re- search.