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为分析一座桥梁结构寿命,在现有混凝土桥梁抗力和荷载的时变性研究的基础上,建立桥梁时变可靠度计算模型。将结构抗力等效转换为车辆荷载作用下结构所产生的竖向位移限值,预测远景交通量,反映荷载的时变性;运用非线性有限单元增量分析方法,以递增特定荷载的方式,采用响应面法计算时变可靠度指标及累计失效概率。结果表明:桥梁结构初始阶段具有足够大的可靠性,但其会随时间推移迅速衰减,利用韦伯分布函数和最小二乘法计算桥梁累计失效概率,进而推算桥梁使用寿命。根据桥梁寿命可靠度计算结果,制定出桥梁最佳维修养护策略。
In order to analyze the life span of a bridge structure, a time-dependent reliability model of bridge is established based on the study of the time-variation of the resistance and load of existing concrete bridges. The structure resistance is equivalently converted into the vertical displacement limit generated by the structure under the vehicle load, the long-distance traffic volume is predicted, and the time variation of the load is reflected. By using the nonlinear finite element incremental analysis method, Response surface method to calculate time-varying reliability index and cumulative failure probability. The results show that the bridge structure has sufficient reliability in the initial stage, but it will decay rapidly with the passage of time. The cumulative failure probability of the bridge is calculated by means of Weber distribution function and least square method, and then the service life of the bridge is calculated. According to the reliability of bridge life calculation results, to develop the best bridge maintenance strategy.