Floor acceleration response spectra of elastic reinforced concrete frames

Abstract

Nonstructural components are the members attached to building structures to realize and maintain the building functionality. Although they are not intended to bear loads, nonstructural components could be subjected to earthquake loading that may lead to failures. The floor acceleration response spectrum is used as the input for the seismic design of acceleration-sensitive nonstructural components. However, it is time-consuming to conduct time-history analyses to generate accurate floor response spectrum for a typical building, and it is therefore not convenient for seismic design. To avoid the computational cost of time history analyses, this study proposes a simplified method based on the modification of an existing methodology for the generation of floor acceleration response spectrum. The first step is to conduct a modal analysis to determine the modal properties of the supporting structure. Then, the floor response spectrum of each mode of the supporting structure is generated and combined based on modal combination rules to obtain the floor response spectrum of the supporting structure. The component dynamic amplification factors that reflect the amplification effects of the nonstructural components on the floor acceleration responses are important for the generation of floor response spectra. Three reinforced concrete moment-resisting frames are designed to evaluate the component dynamic amplification factors for which an empirical fitted formula is proposed to generate more accurate floor response spectrum for structures designed in accordance with Chinese seismic design codes. The results calculated by time history analyses are used to validate the proposed amplification factors and demonstrate the feasibility and effectiveness of the newly modified method.