灵敏度分析在空间钢结构抗连续倒塌控制中的应用

SENSITIVITY ANALYSIS APPLIED ON CONTROL PROGRESSIVE COLLAPSE IN SPECIAL STEEL STRUCTURE

Pandey的灵敏度方法分析结构的冗余度是基于线弹性结构,通过结构中各杆件的应力变化程度来判断结构的冗余度。Pandey的灵敏度方法能一定程度上反映结构的冗余度和鲁棒性,但从抗连续倒塌的角度,该方法具有一定的不足。利用拉、压杆的应力、应变曲线,结合两个计算实例,模拟结构的抗倒塌过程,分析和比较Pandey的灵敏度方法分析空间结构的冗余度在抗连续倒塌方面的不足,说明压杆的屈曲和卸载对抗连续倒塌性能的影响。并在Pandey等提出的基于敏感性分析方法的基础上,根据大跨空间钢结构的结构特性和荷载特点,提出基于频率的敏感性分析方法来判断大跨空间钢结构的关键构件。该方法不仅概念清晰,而且简单易行。

Pandey’s sensitivity analysis on redundancy of the structure is on the basis of linearity and elasticity,and redundancy is estimated by degree of stress variety of all components. The results obtained by the method could reflect redundancy and robustness at a certain extent, but some deficiencies were found from the view of progressive collapse control. Progressive collapse was simulated with stree-strain curve of struts and tie rods through two examples, the analysis and comparision were conducted with the results by Pandey’s sensitivity analysis,and the impacts produced by bucking and uninstall of compression members on progressive collapse were illustrated. On the basis of Pandey’s sensitivity analysis, the method based on frequency sensitivity analysis to judge key member of long-span special steel structure was put forward according to characteristics of structure and load, which is not only distinct on concept, but also easy to practice.