基于失效前可检概率及全寿命成本的桥梁检测制度优化

Optimization of Bridge Inspection Based on Probability of Detection Before Failure and Life-cycle Cost

现阐述桥梁检测制度的优化目标,即构件功能失效前,检测到相关退化信息的概率较大,且检测成本期望值较低。两组目标分别采用失效前可检概率PDBF和全寿命检测成本表示,并建立了由事件树方法计算PDBF的理论模型。全寿命检测成本则通过折现率转换为现值。针对上述优化目标,分别建立了双目标和单目标优化模型。通过算例描述了理论模型的实际应用过程。双目标优化结果显示,随着失效前可检概率的提高,继续增加检测频率的效果较差。但通过Pareto最优解集,可获得PDBF的优化极限,从而对单目标优化时约束条件的选取提供参考。单目标优化模型操作简单,计算耗时较少,可以获得一组最优检测制度,具有更好的实用性。

The objectives of bridge inspection are to achieve two goals.The probability to detect the deteriorative information before structural failure should be high enough,while the inspection cost should be as low as possible.The former was quantified by PDBF(Probability of Detection Before Failure)and the latter was evaluated on the basis of lifecycle concept.Event tree model was utilized to calculate PDBF and annul discount rate was considered to obtain the current value of lifecycle cost.Bi-objective and single-objective optimization models were established respectively.A working example was introduced to illustrate the application of the theoretical framework.The results of bi-objective optimization showed that along with the enhancement of PDBF,increasing of inspection frequency became less efficient.The limit of PDBF could be obtained by the Pareto optimization and then served as a reference to set the threshold of single-objective model.Single-objective optimization was simple and less time-consuming,while the result could provide a definite solution,which was thus more practical.