柱面网壳地震位移需求计算的迭代等效推覆方法

Iterative Equivalent Modal Pushover Method for Seismic Displacement Demand Calculation of Cylindrical Latticed Shells

摘要:

为提高采用推覆方法计算柱面网壳地震位移需求的效率和精度，提出一种改进的推覆方法。基于能量等效原理，建立不依赖中间参数或增量计算的等效单自由度体系。根据等能量原则，提出确定目标位移的迭代等效方法；采用完全二次项平方根方法(CQC)组合各主振型等效体系目标位移处的振型反应得到结构需求。算例结果表明，相比传统的推覆方法，基于迭代等效的推覆方法得到的柱面网壳最大节点位移、整体位移包络的误差较小。当结构反应由多振型共同主导时，该方法的计算精度稳定。

Abstract:

A modified modal pushover method is proposed to improve the efficiency and accuracy of seismic displacement demand calculation of cylindrical latticed shells. First, based on the energy equivalence rule, an equivalent single-degree-of-freedom (ESDF) system for spatial structures is established, in which the equivalent force and displacement of the ESDF system can be directly calculated without using interim parameters or step-by-step calculation. Then, according to the equal-energy rule, an iterative equivalence method is proposed to calculate the target displacement of the ESDF system. Finally, the overall structural seismic demand is obtained by combining the peak responses of dominant modal ESDF systems using the complete quadratic combination (CQC) rule. The numerical results show that compared to the results obtained by using the traditional pushover method, both the maximum and the envelope nodal displacement obtained by using the proposed method yield less error. The accuracy of the proposed method remains stable when structural response is dominated by multiple modes.