The seismic response of multi-storey buildings

Abstract

The draft loading codes, DZ4203, produced in 1986 and 1988, specified different response spectrum curves for different values of structural ductility factor.  This increased the complexity of the design as an analysis based on an elastic response spectrum, which is required for the serviceability limit state, could not be scaled for the ultimate (severe seismic) limit state.

To reduce this complexity a change in the shape of the response spectra used for modal analysis of ductile structures is proposed.  The effects of changing the spectra style is investigated in analyses of a series of elastic analyses of walls and frames.  The results of these analyses are compared with time history analyses of these structures for a number of different ground motions.

The predictions of the equivalent static, modal response spectrum and modal equivalent static methods of analysis are compared for a series of regular wall and frame structures. From these it was concluded that the equivalent static method of analysis is acceptable for regular structures providing the fundamental period does not exceed 2 seconds. For other structures the modal response spectrum method is recommended.