在役钢筋混凝土渡槽多失效模式时变可靠度分析

Time⁃Varying Reliability Analysis of Multi⁃Failure Modes of Reinforced Concrete Aqueducts in Service

传统渡槽可靠度分析大多只考虑失效模式的单一性,为此,基于混凝土碳化模型与钢筋锈蚀模型提出了在役钢筋混凝土渡槽多失效模式的时变可靠度计算方法。利用Monte-Carlo法建立了单一失效模式的时变可靠度与失效概率计算方法,在单一失效模式的基础上采用PNET算法给出了多失效模式时变可靠度模型,运用Matlab软件编写了程序,对某在役钢筋混凝土渡槽结构在单一失效模式与多失效模式下的时变可靠度与失效概率进行了计算分析,结果表明:考虑多失效模式的渡槽可靠度小于单一失效模式的可靠度,计算结果更加合理;考虑渡槽多失效模式的时变性,能更好地掌握结构可靠度随时间的变化情况,给渡槽结构的耐久性做出合理的评价;采用多失效模式时变可靠度对渡槽的可靠度进行计算,与单一失效模式计算结果相比更符合渡槽实际。

Traditional reliability analysis of aqueducts only considers the singularity and time⁃invariance of failure modes.Therefore,based on concrete carbonation model and steel corrosion model,a time⁃varying reliability calculation method for multiple failure modes of in⁃service reinforced concrete aqueducts was proposed.Monte⁃Carlo method was used to calculate the time⁃varying reliability and failure probability of a single failure mode.On the basis of a single failure mode,a time⁃varying reliability model of multiple failure modes was presented by using PNET algorithm.The corresponding program was compiled by using Matlab and the time⁃varying reliability and failure probability of in⁃service reinforced concrete aqueduct structures under single failure mode and multi⁃failure mode were calculated and analyzed.The calculation results show that the reliability value of aqueduct considering multi⁃failure mode is less than that of single failure mode and the calculation results are more reasonable.Considering the time⁃varying of multiple failure modes of aqueduct,the variation of aqueduct structur⁃al reliability with time can be better grasped and the durability of aqueduct structure can be reasonably evaluated.The reliability of aqueduct can be calculated by using time⁃varying reliability of multiple failure modes,which is more in line with the actual situation of aqueduct com⁃pared with single failure mode.