桥梁结构抗震挡块的研究现状与展望

综述了桥梁抗震挡块的几类典型结构形式,对常见挡块的实际震害形式、破坏机理以及力学分析模型的研究现状进行了分析,归纳总结了不同规范中桥梁抗震挡块的设计方法。对当前挡块抗震研究和设计中存在的问题进行了分析和讨论,并提出了一种新型的预应力装配式超高性能混凝土(UHPC)挡块形式。研究结果表明:传统整体式混凝土挡块的主要破坏模式为斜剪和平剪破坏,既有试验中已对两种模式的破坏机理进行了较深入的研究;相比传统整体式混凝土挡块,滑移型混凝土挡块和弹塑性钢挡块在抗震设计中更具可控性,值得进一步在国内推广和应用;美国规范按挡块类型分别给出了不同的设计策略,并对挡块的承载力计算方法和配筋形式进行了说明,值得我国桥梁抗震设计规范借鉴;提出的装配式UHPC挡块具有传力简单明确、自复位和震后修复更换方便等特点,可作为我国中小跨径桥梁结构抗震挡块设计及加固的一种有益补充,值得进一步展开深入的研究。

Research review and prospect of the anti-seismic retaining block for the bridge structures

This study reviewed the typical structural forms of the anti-seismic retaining blocks for the bridges.The seismic failure modes,damage mechanisms and mechanical models of the common used retaining blocks were analyzed.The seismic design methods of the retaining blocks in different seismic design specifications were summarized.The existing problems in the seismic research and the seismic design of the retaining blocks of the bridge structures were analyzed and discussed.Then,a new type of prestressed prefabricated ultra-high performance concrete(UHPC)retaining block was proposed in this paper.The results show that the main failure modes of the traditional integral concrete retaining blocks are the diagonal shear failure and the sliding shear failure.Previous experimental research has investigated the failure mechanism of the above two failure modes.Compared with the integral concrete retaining blocks,the sliding concrete retaining block and the elastoplastic steel retaining block are more controllable in seismic design of the bridge.Therefore,it is worthy of popularization and application in China.The America’s seismic design criteria provides different design strategies according to the types of retaining blocks.Moreover,the calculation method of the bearing capacity and the reinforcement form of the retaining blocks are described in detail.It is worthy of reference for China’s seismic design criteria.The proposed prefabricated UHPC retainer has the advantages of load path clearly,self-centering and easy repairing after the earthquake,etc.Therefore,it can be used as a beneficial supplement to the seismic design and retrofitting of the anti-seismic retaining block of the media-small span bridges in China,and is worth further research.