大跨上承式拱桥拱上建筑碰撞效应多尺度模拟研究  

Multi-scale simulation study on pounding effects of spandrel structures in long-span deck-type arch bridges

作　　者：沈正璇 徐略勤[1,2] 史俊 徐粒寒 SHEN Zhengxuan;XU Lueqin;SHI Jun;XU Lihan(School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区：[1]重庆交通大学土木工程学院,重庆400074 [2]重庆交通大学,省部共建山区桥梁及隧道工程国家重点实验室,重庆400074

出　　处：《自然灾害学报》2024年第2期175-186,共12页Journal of Natural Disasters

基　　金：重庆市教委科学技术研究项目(KJQN201900737);重庆市英才计划项目(cstc2022ycjh-bgzxm0133);重庆交通大学研究生科研创新项目(2022S0008)。

摘　　要：大跨上承式拱桥的拱上建筑属于高度非规则梁式桥跨结构,在地震作用下的碰撞效应不仅有别于普通规则梁桥,而且还会受到拱圈变形的影响。为了探明大跨上承式拱桥拱上建筑在地震作用下的碰撞效应,基于三维碰撞-摩擦分析方法和材料塑性损伤本构关系,采用多尺度模拟研究了某大跨拱桥拱上建筑相邻主梁在伸缩缝处以及主梁与限位挡块之间的碰撞行为与局部损伤特征,并进一步探讨了拱上建筑分联方式对碰撞效应和拱上立柱剪力响应的影响规律。研究表明:全简支的拱上建筑易在1/4跨附近的伸缩缝处产生最大碰撞力,而且由于受主拱空间变形的影响,主梁在伸缩缝处易发生局部偏心碰撞,严重损伤集中于外侧小箱梁;无论拱上建筑采用哪种分联方式,主梁与限位挡块之间最强烈的碰撞效应都发生在拱顶附近;分联方式对碰撞效应有重要影响,采用全连续或分联连续的拱上建筑可大幅降低伸缩缝和挡块2个部位的碰撞力,避免1/4跨附近发生最大碰撞效应。因此,拱上建筑的合理布跨和分联是减轻大跨拱桥碰撞效应的有效途径。The spandrel structures of long-span deck-type arch bridges are highly irregular girder-span structures,in which the pounding effects under earthquakes are not only different from ordinary regular girder bridges,but also affected by the deformation of the arch ring.To explore such pounding effects,the multi-scale simulation was carried out to incorporate the three-dimensional pounding-friction model and the plastic damage constitutive relationships of materials.A long-span arch bridge was selected as an example to investigate the pounding behavior and local damage characteristics of adjacent girders at the expansion joints and also between the girder and retainers.Furthermore,the influences of spandrel structure configurations were discussed on the pounding behaviors and the shear response of columns.The results showed that the simply-supported spandrel structure is prone to produce the maximum pounding forces at the expansion joints near the 1/4 spans.The spandrel girders tend to collide eccentrically due to the influence of the spatial deformation developed in the main arch,which causes serious damage to the exterior box girders.Whichever the spandrel structure configuration is adopted,the strongest pounding effect between the girder and retainers is mainly found near the arch apex.The spandrel structure configuration has a significant impact on the pounding behaviors.When the spandrel structure is continuous or piecewise continuous,the pounding forces generated both at the expansions and retainers can be significantly reduced,and the strongest pounding effect near the 1/4 spans can also be avoided.Therefore,the reasonable span distribution and separation of spandrel structures is an effective way to reduce the pounding effects of long-span arch bridges.

关 键 词：上承式拱桥 碰撞效应 多尺度模拟 拱上建筑 地震响应 

分 类 号：U442.5+5[建筑科学—桥梁与隧道工程]