基于LCA和时变可靠度分析的桥梁维护策略优化

Bridge Maintenance Strategies Optimization Based on Life Cycle Assessment and Time-dependent Reliability Analysis

为研究桥梁在生命周期过程中维护对安全性的提升,及桥梁维护过程所带来的环境影响,基于不确定性的思想,将失效概率作为结构安全性的表征指标,分析了桥梁结构有无维护和进行预防性维护、实质性维护的时变可靠度变化;基于考虑终点破坏模型的生态指标法,做出了桥梁的生命周期环境影响评价(Life cycle assessment,LCA);采用帕累托优化方法进行了失效概率与生命周期环境影响值双目标下的桥梁维护策略优化。运用该方法分析了某钢筋混凝土桥梁在有预防性维护和没有预防性维护情景下,以及预防性维护首次实施时间与实施周期的不同所引起的生命周期累积失效概率和环境影响的变化,并对其维护策略进行了优化分析。结论表明合理安排多次预防性维护能够有效延迟实质性维护的发生时间并降低生命周期环境影响,可以根据对结构安全储备要求和环境影响要求选择桥梁最优维护策略。

In order to research on the effect of maintenance on bridge safety in its life time and environment, based on the uncertainty, we analyzed the time-dependent reliability of bridge structures under three maintenance scenarios, namely, no maintenance, preventive maintenance and essential maintenance. Then, we conducted the bridge life time environmental impact assessment by LCA method, namely eco-indicator considering endpoint damage model. At last, we applied Pareto Optimization to optimize the bridge maintenance strategy integrated the probability of failure and LCA. By using this method, we conducted a case study of a reinforced concrete bridge to analyze the life cycle cumulative failure probability and the impact on environment under the conditions of with/without preventive maintenance, different first preventive maintenance time and maintenance cycles, and optimized the maintenance strategy. The results show that （ 1 ） the reasonable arrangement of several preventive maintenances could effectively postpone the occurrence of essential maintenance and reduce the impact on environment in bridge life cycle; （2） it is feasible to choose the optimal maintenance strategy according to structural safety reserve requirements and impact on environment.