New insights on effects of directionality and duration of near-field ground motions on seismic response of tall buildings

Abstract

Summary The effects of ground motion directionality on seismic response of buildings are at the center of ongoing debate among earthquake engineering professionals and researchers. This has prompted a renewed interest to have a better understanding of directionality effects of near-field pulse-like ground motions on seismic response of tall buildings to further improve seismic design in this respect. In particular the prediction of the maximum displacement response along the structural axis which is called the critical displacement response. This paper presents the results from parametric studies that investigate the directionality effects on nonlinear dynamic response of simple structures and a tall building. The outcome of these analyses was the development of a method, which relies on the maximum velocity to provide a good approximation to the critical displacement response. The method developed is computationally efficient and involves less calculation than other methods. In addition, it was determined that the building responses to records rotated to fault-normal can lead to significant underestimation of the maximum response along the structural axis, using the fault-parallel ground motion also may lead to large response differences and smaller yet significant differences when using the maximum direction ground motion.