确定桥梁评估目标可靠指标的费用效益分析法

结构可靠度理论越来越多地被用到桥梁设计、评估与管理领域。其中一个重要的参数——目标可靠指标的取值直接影响评估结果的合理性。全面考虑了结构在剩余服务期内的结构失效费用、结构养护维修与加固费用和因功能不足引起的附加用户费用,对既有桥梁进行剩余服务期内的费用效益分析,以总费用最小为目标确定可接受的最小结构参数值。通过结构时变可靠度分析方法确定相应于该结构参数的最小目标可靠指标,即为桥梁评估的目标可靠指标值。最后以某钢筋混凝土简支梁桥例证了此方法的可行性与有效性。

Cost-benefit Analysis Method to Determine Target Reliability Index for Assessment of Highway Bridges

Structural reliability analysis has been applied to the design,assessment and management of bridges.The assessment results are dependent on an important parameter,i.e.the target reliability index used in the reliability analysis.A cost-benefit-analysis is conducted aiming at determining the target reliability index for assessment of highway bridge.Three cost components of the total costs during the remaining service life of existing bridge are considered,i.e.the expected cost arising from structural failure,maintenance and intervention,and inadequate serviceability.The optimal structural parameters are deduced from the target function minimizing the total costs.A time-variant probabilistic analysis is conducted to determine the target reliability index.An example of simple beam bridge in the road network of China is analyzed to demonstrate the feasibility and effectiveness of the analysis method.