基于渐进地震失效模式的高层结构抗罕遇地震设计方法研究

Study on seismic design method of high-rise structures resistant to rare earthquakes on basis of progressive seismic failure mode

针对高层结构罕遇地震作用下局部集中损伤破坏易导致整体倒塌的问题,及超静定次数消耗集中且不充分的结构地震失效本质,确定了高层结构耗能构件分批次充分消耗超静定次数的多阶段塑性发展路径,提出了高层结构塑性发展充分、失效方向可控、失效路径延长的渐进地震失效模式。同时,考虑结构多阶段塑性发展过程中地震作用的往复特性、高阶振型影响和非线性内力重分布特点,建立基于多阶段振型组合的标准地震作用,给出了多阶段塑性发展的抗震性能量化需求,建立了基于渐进地震失效模式的高层结构抗罕遇地震设计方法。该方法将高层结构渐进地震失效全过程的复杂设计简化为有限塑性阶段的分段抗罕遇地震设计,解决了高层结构难于抗罕遇地震量化设计的难题。为验证该设计方法的有效性,对一幢10层高层结构进行了抗罕遇地震设计,通过非线性时程分析方法验证了按所提方法设计的结构能够实现结构渐进地震失效模式以及结构抗震性能目标,并对比分析了按所提方法设计的结构与按现行规范方法设计的结构的抗震性能,得到按所提方法设计的结构在地震动峰值加速度为0.22g作用下耗能提高了57%,在非线性静力推覆作用下非线性抗力(基底剪力)最大值提高了15.59%。

Aiming at the problem that the local concentrated damage of high-rise structures under rare earthquakes are easy to lead to structural overall collapse, and the essence of structural seismic failure with concentrated and insufficient consumption of static indeterminate times, this paper determines a multi-stage plastic development path with classified alternating gradual yield of members and fully consuming statically indeterminate times of energy dissipation members in batches for high-rise structures, and the progressive seismic failure mode of high-rise structure is proposed, which is characterized by controllable failure direction, extended failure path of structure, full plastic development.Considering the reciprocating characteristics of earthquake action, the influence of high-order vibration modes and the redistribution of nonlinear internal forces in the process during the multi-stage plastic development of structure, a standard earthquake action based on multi-stage mode combination is established, the quantitative requirements for seismic performance of multi-stage plastic development are given, and the seismic design of high-rise structures against rare earthquakes based on progressive seismic failure mode is proposed, which improves the energy dissipation capacity and nonlinear resistance of structures. In this method, the complex design of the high-rise structure based on the whole process of progressive seismic failure mode is simplified to the piecewise seismic design in the finite plastic stage, which solves the difficult problem of quantitative seismic design of the high-rise structure against rare earthquakes. To verify the effectiveness of this proposed seismic design method, a 10-story high-rise structure against rare earthquakes was designed by the proposed seismic design method. The achievements of structural progressive seismic failure mode and the seismic performance goal were verified by the nonlinear time history analysis method. The seismic performance of the structure designed by the proposed seismic design method and the structure designed by current codes were compared and analyzed. The energy dissipation capacity of the structure designed by the proposed seismic design method is increased by 57% under the action of seismic peak acceleration of 0.22 g, and the maximum nonlinear resistance(base shear) is increased by 15.59% under the action of nonlinear static pushover.