国家体育场大跨度钢结构罕遇地震性能分析

采用杆端塑性铰模型、动力弹塑性分析法和静力弹塑性分析法对国家体育场大跨度钢结构罕遇地震作用下的性能进行了分析。三维动力弹塑性分析的输入包括4组地震记录和1组人工地震波;静力弹塑性分析包括单向、双向和三向推覆共12种工况。结果表明,罕遇地震作用下,国家体育场大跨度钢结构最大位移小于其限值;主结构的塑性铰主要出现在桁架柱,数量很少,且屈服程度较轻;次结构的塑性铰数量少,极少数铰的强度下降至残余强度;结构的整体刚度没有下降,承载能力未达到最大。国家体育场大跨度钢结构设计达到了预定的抗震设防性能目标。对静力和动力弹塑性分析两种方法的结果进行了比较,探讨了静力弹塑性分析合适的加载模式,为大跨度钢结构的静力弹塑性分析提供了参考。

Seismic behavior analysis of large-span steel structure of the National Stadium under severe earthquake

Study of seismic behavior of large-span steel structure of the National Stadium was performed by dynamic elasto-plastic analysis method and static elasto-plastic analysis and capacity spectrum method under severe earthquake excitation.Elements with concentrated plastic hinge were adopted for the analytical model.The input motion for the dynamic elasto-plastic analyses included 4 earthquake records and 1 artificial wave.Static elasto-plastic analyses included 12 loading cases.Results of both dynamic analysis method and capacity spectrum method indicate that under severe earthquake the maximum displacement is much less than the limit value,few members of the main structure yield slightly,a few plastic hinges are formed in the secondary structural members and the load-carrying capacity of few of them is lost,but the stiffness and the load-carrying capacity of the structure is not decreased.The analytical results indicate that the design of the steel structure of the National Stadium achieves the earthquake performance objectives.Loading pattern of pushover analysis is discussed by evaluating dynamic analysis results and static analysis results,which may be a reference for future seismic behavior study of large span steel structures.