Multi-Mode Response of Shear and Flexural Buildings to Pulse-Type Ground Motions in Near-Field Earthquakes

This article presents an investigation of multi-mode effect of tall buildings subjected to near-field pulse-like ground motions. Multi-story buildings are modeled as an equivalent continuum structure consisting of a combination of a flexural cantilever beam and a shear cantilever beam. The simplified model is subjected to near-field ground motions and the representative simplified pulses. The maximum interstory drift spectra and its location along the height are calculated on the basis of modal summation approach. So, the method is largely based upon the assumption of linearity of the system. The effects of shear to flexural deformation ratio, structural to input pulse period ratio, and the velocity pulse shape on the structural response are discussed. The applicability of first-mode estimation is also investigated. In the end, it is shown that the response of structures to near-field pulse-like ground motions can be predicted by the structural response to the simple velocity pulses.