薄壁拉筋矩形钢管混凝土墩柱抗震性能研究  

Research on seismic performance of thin-walled stirrup-confined rectangular concrete filled steel tube piers

作　　者：孙浩 吕飞 丁发兴[1] 李彪[1,2] SUN Hao;LÜFei;DING Faxing;LI Biao(School of Civil Engineering,Central South University,Changsha 410075,China;China Railway Third Engineering Group Co.,Ltd.,Taiyuan 030001,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中铁三局集团有限公司,山西太原030001

出　　处：《铁道科学与工程学报》2024年第4期1495-1508,共14页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51978664,52008400);湖南省自然科学基金资助项目(2022JJ40609)。

摘　　要：相比圆钢管混凝土墩柱,矩形钢管混凝土墩柱的惯性矩大、稳定性强,但其对填充混凝土的约束较差。为探究端部拉筋和加载方向对矩形钢管混凝土墩柱抗震性能的影响,开展2根方形和2根矩形钢管混凝土墩柱的拟静力试验,分析比较端部拉筋以及加载方向对桥墩的刚度、承载力、耗能、刚度退化以及残余变形的影响规律。并采用ABAQUS有限元软件建立拉筋钢管混凝土桥墩精细三维实体-壳单元模型,有限元模型中混凝土单元引入裂缝,钢材引入韧性损伤以考虑更准确的拉筋钢管混凝土桥墩的抗震性能退化规律。研究结果表明:与传统钢管混凝土桥墩相比,端部拉筋约束钢管混凝土墩柱的屈服荷载、水平峰值荷载、累计耗能和弹性刚度分别提高49.3%、42.8%、24.1%和15.1%,抗震性能优于传统钢管混凝土桥墩。与弱轴加载相比,强轴加载时桥墩的屈服荷载、峰值荷载累积耗能和弹性刚度分别提高了45.1%、44.9%、51.7%和7.1%,表明强轴加载时更易发挥抗震性能。采用有限元软件建立的钢管混凝土桥墩精细三维实体-壳单元模型与试验结果吻合良好,反映了循环荷载下拉筋钢管混凝土桥墩的塑性大变形阶段承载力退化现象和滞回曲线“捏拢”效应。有限元模型计算的裂缝高度位置与试验结果基本一致。研究结果可为进一步优化钢管混凝土墩柱的设计提供参考。Compared to circular concrete filled steel tube(CFST)piers,rectangular CFST piers have a larger moment of inertia and stronger stability but have poor constraints on filling concrete.To investigate the influences of end stirrup and loading direction on improving the seismic performance of rectangular CFST piers,quasi-static tests were conducted on two square and two rectangular CFST piers.The study analyzed and compared the effects of end stirrup and loading direction on the bridge piers’stiffness,bearing capacity,energy dissipation,stiffness degradation,and residual deformation.Additionally,a refined three-dimensional solid-shell finite element model of the stirrup CFST piers was established using ABAQUS software,where cracks were introduced in the concrete elements,and ductile damage was introduced in the steel tube elements to consider more accurate degradation patterns of the seismic performance of CFST piers.The research results showed that compared to traditional CFST piers,end stirrup increased the yield load,horizontal peak load,cumulative energy dissipation,and elastic stiffness of restrained steel tube concrete piers by 49.3%,42.8%,24.1%,and 15.1%,respectively,indicating better seismic performance than traditional CFST piers.Compared to weak axis loading,strong axis loading increased the yield load,peak load,cumulative energy dissipation,and elastic stiffness of the piers by 45.1%,44.9%,51.7%,and 7.1%,respectively,indicating that the seismic performance is more effectively utilized under strong axis loading.The refined three-dimensional solid-shell finite element model of the CFST piers established using ABAQUS software showed good agreement with the experimental results and reasonably reflected the“pinching”effect of the hysteresis curve and the degradation of load-carrying capacity during the plastic large deformation stage of the stirrup steel tube concrete piers under cyclic loading.The crack height positions calculated by the finite element model were consistent with the experimental results.

关 键 词：拉筋 钢管混凝土 墩柱 抗震性能 有限元 

分 类 号：U433.22[交通运输工程—道路与铁道工程]