基于LHS-Kriging法的正交异性钢桥面板疲劳可靠度分析

Fatigue reliability analysis of orthotropic steel bridge deck based on LHS-Kriging method

为解决随机车载下正交异性钢桥面板疲劳应力谱有限元求解耗时问题,采用拉丁超立方抽样(LHS)与Kriging方法,建立了快速获取随机车流作用下细节疲劳应力谱的LHS-Kriging有限元替代模型,并将此模型应用于南溪长江大桥正交异性钢桥面板疲劳可靠度计算。结果表明,基于LHS-Kriging方法的有限元替代模型,不需要经过大量车辆荷载的有限元加载,可直接快速获取细节疲劳应力谱;与传统的响应面法(RSM)相比,Kriging法预测的细节等效疲劳应力更符合有限元计算结果;随着交通量增长率的增大,桥梁的疲劳可靠度显著减少;100年后,当交通量增长率为3%和5%时,正交异性桥面板与纵肋焊接处的细节疲劳可靠度小于2。

In order to solve the time-consuming problem of finite element solution of fatigue stress spectrum of orthotropic steel bridge under random vehicles,Latin Hypercube Sampling（LHS）and Kriging method were used to establish a LHS-Kriging finite element replacement model for quickly obtaining the detailed fatigue stress spectrum under random traffic flow.And the proposed replacement model was applied to fatigue reliability calculation of orthotropic steel bridge decks of Nanxi Yangtze River Bridge.The results show：the detailed fatigue stress spectrum can be rapidly obtained by the LHS-Kriging finite element replacement model without large number of finite element analyses;compared with the RSM method,the predicted value of the Kriging method is more consistent with finite element calculation;with the increase of traffic growth rate,the fatigue reliability of bridge is significantly reduced;after 100 years,the fatigue reliability between the orthotropic bridge deck and longitudinal rib welding is less than 2 when the traffic growth rate is 3% and 5%.