Nonlinear dynamic analysis of frame-core tube building under seismic sequential ground motions by a supercomputer

Historical records indicate that strong earthquakes are usually accompanied by aftershocks with large peak ground accelerations. Structural damages caused by the mainshock can be further aggravated by aftershocks, which can lead to structural collapse. Current structure seismic design practices generally consider the mainshock effects only. Performance of buildings subjected to mainshock-aftershock sequential ground motions, should always be fully investigated. Previous studies on sequential ground motion focus mainly on frame structures. There is a paucity of publications addressing other type of structures, especially high-rise buildings. The reasons for this omission have been identified as the complexity of high-rise buildings and unaffordable computational costs related to the nonlinear dynamic analysis of long duration sequential ground motions. Thus, the authors used Tianhe-2, once known as the fastest supercomputer in the world, to conduct nonlinear dynamic analysis of a typical 20-story frame-core tube building subjected to sequential mainshock-aftershock ground motions. This study focuses on 104 mainshock and aftershock ground motions from four different sites. Thus, the effects of mainshocks only and sequential ground motions of a frame-core tube structure at four different sites were analyzed in this study's finite element model. The Performance of these structures under mainshocks and sequential ground motions are compared in terms of inter-story displacement ratio, hysteretic energy and damage index based on the Park-Ang model. The results prove that a supercomputer can be used to solve the computational cost issue in structural engineering and emphasize that the effects of sequential earthquakes need to be considered in structural design, even for frame-core tube structures with lateral resisting members.