Seismic and collapse behavior of existing high-rise steel buildings under long-period earthquakes

This work presented the experimental and numerical evaluation of the seismic and collapse behavior of Japanese existing high-rise steel buildings subjected to long-period ground motions (LPGMs). Initially, the experiment (E-Defense, 2008) was performed by the full-scale shaking table tests on a typical 21-story steel frame substructure. Accordingly, a nonlinear rotational spring model was used in the numerical modeling. In consideration of the stiffness/strength deterioration and fatigue fracture of beam-column connections, the cyclic pushover analysis was utilized to account for such effect using seismic response data from system-level testing. Subsequently, the numerical model parameters were derived and validated with the initial experiment on the high-rise steel frame substructure. Herein, a well agreement on the seismic failure behavior between simulation and experiment was found in this situation. Furthermore, both field-welded and shop-welded connections on the seismic performance were included for comparison. For the 21-story prototype steel building (built before 1970s), a series of numerical collapse analyses were performed. The above revised model using nonlinear static pushover analysis and time history analysis were conducted to simulate and compare the effects of connection details and composite slabs on the 21-story prototype building. Finally, a cyclic loading protocol for simulating LPGMs was proposed, and the related ultimate failure behavior of the high-rise building was analytically discussed. Critically, this work should provide a viable strategy to numerically simulate the seismic and collapse behavior of high-rise steel buildings in this progressing construction field.