大跨移动式风雨棚基于性能的概率地震易损性分析

Performance-based probabilistic seismic vulnerability analysis of a large-span mobile storm shed

大跨移动式风雨棚是应用于船厂、工矿、军工等为克服恶劣天气而在场地不同位置设置的可移动棚式特种机械设备。由于该结构多在近海地区投入使用,且近海地区多是地震频发地带,所以对大跨移动式风雨棚进行基于性能的概率地震易损性分析是非常有必要的。以地震峰值加速度(PGA)作为地震动强度指标,以顶点最大位移角和位移延性比作为地震需求指标,并基于文献和文中定义的界限值法对结构进行易损性分析,最终得到结构在不同极限状态下的易损性曲线。通过模拟研究得出:该定义界限值法的结构失效概率大于基于文献界限值的结构失效概率。对于大跨移动式风雨棚可以参考该界限值法对结构进行地震易损性分析。不同地震需求指标和相同PGA下,以顶点最大位移角为指标的结构倒塌概率(78.19%)略小于以位移延性比为指标的结构倒塌概率(78.59%),因此可以以位移延性比为首要考虑的指标,以顶点最大位移角作为对比指标为结构提供今后的震害预测参考数据。

Large-span mobile wind and rain shed is used in shipyards,mining,military industry and other portable shed special mechanical equipment set up in different positions of the site to overcome the bad weather.Since the structure is mostly put into use in the offshore areas,and the offshore areas are mostly seismic frequent areas,it is very necessary to conduct performance-based probability seismic vulnerability analysis on the large-span mobile storm shed.The seismic peak acceleration(PGA)is taken as the ground motion strength index,the maximum displacement angle and displacement ductility ratio are taken as the seismic demand index,and the vulnerability is analyzed based on the boundary value method defined in this paper,and the vulnerability curve of the structure in different limit states is obtained.Through simulation research,it is concluded that the structure failure probability of the defined boundary value method is greater than the structure failure probability based on the limit value of the literature.For the large-span mobile storm canopy,the structure can be analyzed by using the boundary value method defined in this paper.The collapse probability of maximum displacement angle of vertex(78.19%)is slightly less than that of displacement delay ratio under the same PGA(78.59%),therefore,the displacement ductility ratio can be considered as the primary index,with the maximum displacement angle of the vertex as the comparison index to provide future reference data for earthquake damage prediction for this structure.