考虑构件震害影响的城市桥梁震后通行功能损失评估方法

Post-earthquake urban bridge traffic capacity loss assessment considering effects of structural component damage

摘要:

桥梁作为城市交通网络重要节点,其车辆通行能力在震后救灾和重建过程中起着至关重要的作用。但现有城市桥梁震后损失研究多集中于结构损伤维修成本方面,对桥梁震后车辆通行功能损失研究关注不足,难以为震后紧急救援和桥梁修复决策提供有效指导。因此,本文提出了综合考虑桥梁构件震害破坏及其对车辆通行影响的桥梁震后通行功能损失评估方法。首先,为了更准确地分析地震对桥梁结构整体系统的影响,采用copula函数,开展了考虑桥梁构件破坏相关性的桥梁系统地震易损性分析；其次,提出了地震导致桥梁车辆通行能力损失的评估方法。该方法综合考虑了桥梁结构损伤、承载力下降导致的开放车道减少以及桥梁伸缩缝损坏导致的车辆行驶速度降低等因素影响,因而可以更准确地反映震后桥梁车辆通行能力；最后,通过一个4跨连续梁桥算例发现相较于现有评估方法,本文提出的城市桥梁震后通行功能损失评估方法具有准确度更高、离散程度和不确定性更小的特点。与传统的定性和主观震后桥梁功能损失评估方法相比,本项研究提出的分析方法从物理层面考虑了桥梁构件震害对桥梁车辆通行能力的具体影响,为震后决策过程提供了一个数学模型。

Abstract:

As key components in urban transportation network, bridges play crucial roles in post-earthquake relief and reconstruction efforts. However, existing studies on post-earthquake losses of urban bridges primarily concentrate on repair costs for structural damage, paying less attention to the loss of vehicular traffic capacity, which makes it difficult to provide effective guidance for post-earthquake emergency responses and bridge rehabilitation decisions. Therefore, in this paper a method was proposed to assess the loss of post-earthquake traffic capacity of a bridge by comprehensively considering the seismic damage to bridge components and its impact on vehicular traffic. Firstly, in order to accurately analyze the effect of the earthquake on the bridge structure system, a seismic fragility analysis of the bridge system was conducted using the copula function, considering the interdependence of damage to bridge components. Secondly, an evaluation method was proposed for estimating the loss of traffic capacity in bridges due to earthquakes. Finally, the proposed method for assessing post-earthquake vehicular traffic capacity loss of urban bridges was tested through an example of a 4-span continuous girder bridge, which proves that it is more accurate and has less dispersion and uncertainty compared to existing assessment methods. Compared to traditional qualitative and subjective postearthquake functionality assessment of the damaged bridge, the proposed analytical approach considers the specific impact of seismic damage to bridge components on the traffic capacity of the bridge from a physical perspective, and offers a mathematical model for the decision-making process.