考虑地震与爆炸组合作用下梁桥减震体系的性能与可靠度研究

In recent years, the transportation of dangerous goods is increasing in our country, which leads to frequent vehicle explosion accidents, and it's a potential threat to the safe operation of bridges. Further study is needed to ensure the safety of bridges, which are designed based on seismic performance, under blast loading. In addition, when an earthquake occurs, it's highly possible that trucks loaded with dangerous goods will explode due to crashes. However, the research of security capability of bridge under the extreme load combination of earthquake and explosion is insufficient, which leads to potential unsafe elements during operation. Because of such problems, the project focuses on the reliability of the girder bridges with seismic isolation system under the combination effect of earthquake and explosion, using the reliability assessment method based on vulnerability analysis. The works mainly include: (1) the vulnerability analysis of girder bridge under seismic load; (2) researches on explosion level of the dangerous goods transport vehicle; (3)the vulnerability analysis of girder bridge under the impact of blast loading; (4) the conduction of a safe and feasible blast impact experiment; (5) the vulnerability analysis of girder bridge under the combination effect of earthquake and explosion, determining the coefficient of load combination factor; (6)researched on the global approach and local protection measures to decrease the impact of earthquake and explosion from structural system perspective. Research results can provide reference for bridge design and disaster protection.

近年来，随着我国危险品运输量的增大，交通运输爆炸事故频发，这对桥梁来说是一种潜在的威胁，现有的基于抗震性能设计的桥梁结构能否抵抗住爆炸荷载的冲击还有待研究，另外，当地震发生时，容易催生危险品运输车发生爆炸，针对地震与爆炸组合作用的极端情况，桥梁结构的安全性能研究目前还基本没有涉足，这些都为桥梁的安全运营留下了隐患。因此本课题以减震体系梁桥为研究对象，采用基于易损性分析的可靠度评估方法，研究桥梁结构在地震与爆炸荷载组合作用下的可靠度问题。主要内容包括：（1）梁桥在地震荷载下的易损性分析；（2）研究危险品运输车的爆炸等级；（3）梁桥在爆炸冲击下的易损性分析；（4）设计安全可行的爆炸冲击试验；（5）梁桥在地震与爆炸组合作用下的易损性分析，确定荷载组合系数；（6）从结构体系上研究适应桥梁减震兼顾防爆的整体方案和局部防护措施。研究成果可为桥梁设计与抗灾防护提供参考依据。

桥梁结构作为重要的交通基础设施，面临着恐怖袭击、交通运输爆炸事故和地震灾害的威胁，而多灾害作用下桥梁结构的易损性与可靠度问题是工程防灾领域近年的研究热点。因此，本项目以减震体系梁桥为研究对象，采用基于易损性分析的可靠度评估方法，对桥梁结构在地震、爆炸荷载单独与组合作用下的可靠度问题进行了深入的研究，发展了能够考虑地震与爆炸组合作用的非线性有限元分析方法，揭示了地震、爆炸荷载单独和组合作用下桥梁结构的动力响应和破坏模式、机理，形成了考虑地震作用影响的梁桥抗震防爆体系，建立了考虑多灾作用效应的桥梁结构的易损性与可靠度分析方法，设计并开展了小比例尺的缩尺模型振动台模拟冲击试验，对结构在地震和爆炸作用下的响应特点与理论分析方法进行了验证，研究成果为我国的桥梁设计与抗灾防护提供了参考依据。