EFFECT OF BUILDING STIFFNESS AND STRENGTH ON THE SEISMIC SAFETY OF NONSTRUCTURAL BUILDING COMPONENTS

Abstract

Nonstructural components, services and equipments in a building are sensitive to floor accelerations and/or inter-storey displacements. When a building is subjected to an earthquake ground motion, the building amplifies this motion, resulting in floor accelerations higher than the Peak Ground Accelerations. Further, the frequency content of the motion is also modified, as the building acts as a filter to the ground motion. Nonstructural components are subjected to these amplified accelerations, and if the natural periods of the nonstructural components are close to those of the structure, the components can experience Peak Component Acceleration that is much higher than the Peak Floor Acceleration. This can cause severe damage to nonstructural components and their attachments to the structure. Estimation of floor accelerations and drift demands which lead to better design of acceleration and inter storey drift sensitive components can improve the performance of building-equipments. In this dissertation, the amplification of ground motion along the height of buildings having different heights, time periods and strengths has been studied. Three dimensional models of buildings having four, eight and sixteen stories with similar plan have been considered for the study. The buildings are designed based on appropriate building codes. Linear and nonlinear time history analysis has been carried out to find the floor responses of the buildings. Different levels of earthquakes are taken to study the effect of strength. The floor response and storey drifts in frame buildings subjected to different levels of excitation and the effect of building stiffness on the floor response and inter-storey drift by providing shear walls have also been studied. The amplification of ground motion along the height, and the Component Amplification Factor, near resonance, has been studied. The various results have also been compared to the different codes of practice.