Pushover analysis of National Swimming Center

A kind of new polyhedron spatial frame structure is used in upper steel structure of National Swimming Center(NSC).The new structure is used in practical engineering for the first time.As its behavior is different from common grid steel structures,the study of seismic performance on this kind of structures has not been carried out by now.This paper investigates its static elasto-plastic behavior in two horizontal directions by pushover analysis in order to estimate the seismic performance of this structure.The elasto-plastic behavior of the members is modeled by setting hinges into members connections with software SAP2000,and the computing time is reduced markedly by reasonable simplification.The walls and the roof of the building are also consisted of a kind of polyhedron,which are similar to one-story spatial frames.Based on dynamical characteristic,the equivalent horizontal seismic force in two directions are simulated by the first modal force.Analysis is carries out for the capacity-demand spectrum and hinge development process;the good seismic performance of this new structure is proved.After part of the members yield,the stiffness of the structure perform a slow degeneration,the internal force of the structure is redistributed.The structure of NSC is able to satisfy the requirements of seismic design.