基于NSGA-II的城市桥梁系统震后可恢复性分析与优化

STUDY ON EARTHQUAKE RESILIENCE ANALYSIS AND OPTIMIZATION FOR URBAN BRIDGE NETWORK SYSTEM BASED ON NSGA-II ALGORITHM

  • 摘要: 城市桥梁是经济和社会发展的重要基础设施,特别是重要桥梁以及由其构成的网络在灾难发生后如何快速恢复,对社会安定和地区发展十分重要。近年来抗震韧性倍受关注,如何考虑结构可恢复性并将韧性纳入桥梁系统抗震性能综合评估和优化,还存在很多问题尚待研究。该文定量分析桥梁震后恢复过程、剩余功能和修复时间与韧性指标间的联系,建立城市桥梁系统性能评估方法。由桥梁不同损伤状态计算不同恢复过程的剩余功能、修复时间、可恢复性和震后经济损失;对震后恢复过程的功能函数模型给出建议,量化不同震后恢复策略的影响;将韧性纳入城市桥梁系统抗震性能框架中,提出城市桥梁系统震后可恢复性评估框架,对风险高低不同采用不同的修复过程;对震后经济损失、可恢复性和震前修/改造成本采用多目标优化算法NSGA-II求解震前提升韧性优化策略,用于抗震加固措施的选取。通过案例给出了方法流程,也为城市桥梁系统地震韧性提升提供了新思路。

     

    Abstract: Urban bridges are important infrastructure that affects regional economy and social community. When subjected to strong earthquakes and other disasters, the seismic performance of urban bridge structures, especially the resilience of the transportation system composed with key bridges, are very important to social stability and regional economy development. In recent years, the seismic resilience had attracted the attention of researchers. To incorporate the recoverable performance and the resiliency measurement into the evaluation and optimization of the seismic performance of a bridge system, there are still many issues to be studied. This paper further quantitatively analyzes the post-earthquake recovery process, residual function, idle time and repair time, and their influence on the resilience index. And the performance assessment process of urban bridge system was developed. According to the different damage states of the bridge, the resiliency indexes, the repair time, the economic loss after the earthquake and the recoverability of different recovery strategies are calculated. The model of the post-earthquake recovery process is proposed for quantitatively evaluating the recovery stratigies. The resilience is included in the evaluation framework of the seismic performance of the urban bridge system, and the post-earthquake recoverability evaluation framework of the urban bridge system is proposed so that decision makers with different risk-bearing capabilities can make decisions on different recovery processes. The post-earthquake economic loss, resiliency and pre-earthquake repair/reconstruction cost are used in conjunction with the multi-objective optimization algorithm, NSGA-II, to seek a pre-earthquake resilience improvement strategy for the help of selecting maintenance or resilience improvement measures. The calculation of the proposed method is given as an example, which provides new ideas for improving the seismic resiliency of urban bridge system.

     

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