Collapsing Response of a Nonlinear Shear-Beam Building Model Excited by Horizontal and Vertical Strong-Motion Pulses at Its Base

The sequence of collapsing stages of buildings during strong earthquake shaking is still a poorly understood phenomenon. This study aims to use numerical simulations to improve our understanding of the sequence of phenomena that accompany the collapse of buildings during damaging earthquakes. For that purpose, we use a nonlinear shear-beam model of a building that is excited by a sequence of large horizontal and vertical displacement pulses at its base. The propagation of the input pulses through the structure is simulated by a finite difference scheme. We select the properties of our model to be similar to those of a seven-story hotel in San Fernando Valley of the Los Angeles metropolitan area, which was damaged during the 1994 Northridge, California earthquake. We present results of one example of collapsing response of the model to hypothetical but plausible ground motion close to an earthquake fault. We illustrate the response only for a sequence of horizontal and vertical pulses. We show the differences in the nature of the collapsing sequence for vertical upward and downward pulses of ground motion. Rocking input motions will be added in our future work. Improved understanding of the stages of collapse of buildings will be useful for the development of design strategies to prevent it.