节段拼装桥墩撞击试验研究与数值分析  

Experimental Test and Numerical Simulation of Precast Segmental Piers Subjected to Impact

作　　者：方海[1] 陈志跃 刘伟庆[1] 万云磊 祝露[1] FANG Hai;CHEN Zhi-yue;LIU Wei-qing;WAN Yun-lei;ZHU Lu(College of Civil Engineering,Nanjing Tech University,Nanjing 211816,Jiangsu,China)

机构地区：[1]南京工业大学土木工程学院,江苏南京211816

出　　处：《中国公路学报》2021年第7期270-283,共14页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52078248,51778285);江苏省杰出青年基金项目(BK20190034)。

摘　　要：为研究采用节段拼装桥墩与整体现浇桥墩在抗撞击性能方面的差异,探究撞击作用下节段拼装桥墩的撞击响应和破坏模式。采用缩比模型,通过水平撞击试验获得节段拼装桥墩和整体现浇桥墩的动力时程响应曲线,观测不同构造形式桥墩在不同撞击速度下的破坏模式,并对比分析桥墩在撞击荷载作用下的撞击力、位移等动力时程响应;采用非线性有限元模型,对桥墩撞击响应和破坏过程进行仿真模拟,并通过与试验结果进行对比,验证其有限元结果的可靠性;通过参数分析探明了撞击高度、预应力值对拼装式桥墩动力响应的影响规律。研究结果表明:在撞击荷载作用下,整体现浇桥墩主要发生了由受拉弯曲破坏转变为墩底斜向剪切破坏的弯剪破坏,节段拼装桥墩主要发生受撞节段剪切滑移和加载区混凝土压溃;与整体现浇桥墩相比,在撞击作用下节段拼装桥墩撞击力峰值降低21.25%,撞击持续时间相应增加147.62%,同时节段拼装桥墩展现出更强的变形能力和能量耗散能力,但未能展现出良好的自复位能力,增加混凝土局部损伤;有限元模拟与试验结果吻合良好,验证了有限元模型的正确性;基于节段拼装桥墩有限元模型,分析得到撞击高度和预应力值对桥墩撞击力的影响较小,但撞击高度对桥墩变形影响较大,预应力值对桥墩整体刚度也有较大影响;因此,在节段拼装式桥墩抗撞设计时应综合考虑撞击高度和预应力值对桥墩的影响,从而保证结构的可靠安全。This study investigated differences in anti-collision performance between precast segmental piers and overall cast-in-place piers,and explored the impact responses and failure modes of precast segmental piers subjected to impact.A reduced-scale model was used,and the dynamic time history response curves of the precast segmental pier and overall cast-in-place pier were obtained through a horizontal impact test.The failure modes of the piers under different impact velocities were observed.The dynamic responses of piers with different structures under impact,such as impact force and displacement,were compared and analyzed.A nonlinear finite element(FE)model of pier impact was established and a numerical simulation of the impact responses and failure modes of piers was carried out.The reliability of the results was verified by experimental test results.The influence of impact height and prestress value on the dynamic response of segmental piers were analyzed by the parameter analysis method.The research results show that under impact,the failure mode of the overall cast-in-place pier changes from tension bending failure to oblique shear failure at the bottom of the pier,and for the segmental piers,the shear slip and concrete crushing occur mainly in the impact segment.Compared with the overall cast-in-place piers,the peak impact force of the segmental pier decreases by 21.25%and the impact duration increases by 147.62%.At the same time,the segmental pier shows stronger deformation ability and energy dissipation ability,but fails to show good self-reset ability,increasing the local damage of concrete.The FE results are in good agreement with the test results,which verifies the correctness of the FE model.Based on the FE model of the precast segmental pier,the impact height and prestress value have less impact on the impact force,but the prestress value and impact height have a significant impact on the deformation and stiffness of the entire pier,respectively.Therefore,the impact height and prestress value should be c

关 键 词：桥梁工程 拼装式桥墩 水平撞击试验 动力响应 数值分析 

分 类 号：U433.22[交通运输工程—道路与铁道工程]