A DESIGN APPROACH FOR COMPOSITE FRAMED STRUCTURES USING THE HYBRID FORCE/DISPLACEMENT (HFD) SEISMIC METHOD

摘要

A family of regular planar composite steel/concrete MRFs consisting of I steel beams and concrete filled steel tube (CFT) columns are subject to an ensemble of ordinary (far-field type) ground motions scaled to different intensities in order to accommodate different performance levels. On the basis of thousands of non-linear dynamic analysis results, simplified formulae which offer a direct estimation of seismic displacement, drift and ductility demands are presented. Furthermore, a simple expression to estimate the strength reduction factor q, which describes the seismic strength requirements in order to restrict maximum roof ductility demand to a predefined value, is also presented. Emphasis is given to the ability of the proposed formulae to be adjusted to the framework of the hybrid force/displacement (HFD) seismic design method which utilizes response spectrum analysis. A design example reveals the efficiency of the HFD method in comparison with the procedures adopted in current seismic design codes.