大跨度张弦梁结构易损性及评估分析

Fragility analysis and assessment of large-span beam string-structures

由于超越荷载和罕遇地震的作用,大跨度张弦梁结构可能由此而发生整体或连续倒塌。考虑结构和抗力的不确定性,分析了在超越荷载和罕遇地震下结构的易损性。首先,基于蒙特卡洛法和拉丁超立方抽样法,研究活荷载的超越幅度与结构失效概率之间的关系,绘制其静力易损性曲线;其次,基于增量动力时程分析方法,研究不同地震波作用与结构失效概率之间的关系,绘制结构倒塌易损性曲线;最后,研究不同预应力水平对其易损性的影响。结果表明,基于易损性曲线可预测结构在超越荷载和罕遇地震下的失效概率;大跨度张弦梁结构易损性较低;适当提高预应力水平,可以改善结构易损性。

Due to beyond loads and rare earthquakes,full failure and progressive collapse may be happened on large-span beam string-structures.Considering the uncertainty of structure and resistance,fragility analysis on beam string-structures has been finished under beyond loads and rare earthquakes.At first,employing Monte Carlo and Latin hypercube sampling methods,the relationship between alive load amplitude and the failure probability was studied,the static fragility curves were drawn.Secondly,based on time-history method,the relationship of seismic intensity and the failure probability of structural collapse was considered,the seismic fragility curves were gotten too.The influence of different pre-stress distribution on structural fragility was also discussed and the following results were obtained.Fragility curve can predict the failure probability of structure under beyond loads and rare earchtuqkes,large-span beam string-structures have lower fragility,and as the pre-stress increases,the performances of structure are improved.