型钢混凝土闸墩的时变可靠度分析

Time-varying reliability analysis of steel reinforced concrete gate piers

型钢混凝土闸墩是一种刚度大、承载力高的新型闸墩结构.为了研究型钢混凝土闸墩的时变可靠度,基于结构可靠度理论,把时间作为变量,将混凝土的抗压强度作为随时间变化的参数,以10年作为一个时间点,利用ANSYS概率设计模块中的响应面法拟合出响应面方程,结合JC法计算出型钢混凝土闸墩的可靠指标,研究其在设计基准期内的可靠指标的变化趋势,通过灵敏度图分析各个参数对闸墩可靠度的影响。结果表明:在设计基准期内,型钢混凝土闸墩在对称和非对称工况荷载作用下的可靠度变化趋势均是先增大再减小,总体变化趋势是减少的。闸墩在对称工况荷载作用下20~30年的可靠指标下降较快,非对称工况荷载下则在10~20年期间下降较快。随着时间和抗力的变化,非对称工况荷载下的闸墩可靠度减小的速度较快,应尽量减少闸墩在非对称工况下运行的时间。

Steel reinforced concrete pier is a new type of pier structure with high stiffness and high bearing capacity.In order to study the time-varying reliability of steel reinforced concrete piers,based on the structural reliability theory,taking time as a variable,the compressive strength of concrete as a parameter with time,and taking 10 years as a time point,the response surface equation is fitted by using the response surface method in the ANSYS probabilistic design module.Combined with JC method,the reliability index of steel reinforced concrete piers is calculated,and the changing trend of reliability index in the design reference period is studied.The influence of various parameters on the reliability of gate pier is analyzed by sensitivity diagram.The results show that during the design reference period,the reliability of SRC piers under symmetrical and asymmetric loads increases at first and then decreases,and the overall change trend decreases.The reliability index of gate pier decreases rapidly in 20-30 years under symmetrical load and decreases rapidly in 10-20 years under asymmetric load.With the change of time and resistance,the reliability of gate pier under asymmetric load decreases faster,so the running time of gate pier under asymmetric working condition should be reduced as much as possible.