Nonlinear time history analysis of a super‐tall building with setbacks in elevation

Standing 260 m above the ground, the super‐tall building employs steel reinforced concrete frame and reinforced concrete core wall system strengthened by a belt truss story to resist lateral and vertical loads. It has two setbacks in elevation. One is structurally designed by direct termination of vertical members, and the other is realized by inclining columns. Because of these characteristics, the building is classified as an irregular and complex structure. To investigate the seismic behavior of the structure under rare earthquake action, a refined finite element model was developed by using ABAQUS (Dassault Systèmes Simulia Corp., Providence, RI, USA). Nonlinear time history analyses were conducted using explicit integration method. The results show that the structural system has sufficient seismic capacity and ductility to resist rare earthquake. The plastic deformation capacity of this building can meet the requirement of Chinese code, and seismic performance objective of no collapse under rare earthquake can be reached. However, deformations were found concentrated in members within and adjacent to setback stories, at the bottom strengthening portion of core walls and its upper story where lateral stiffness suddenly changed. It was suggested that transfer stories should be placed above or below these stories to improve the concentration of strain and deformation. Copyright © 2011 John Wiley & Sons, Ltd.