新型柔性桥台整体桥梁结构与受力性能研究  

Research on Structural Configuration and Mechanical Property of Flexible Abutment Integral Bridge

作　　者：黄福云[1] 李岚 陈治雄 俞登敏 刘帆 HUANG Fuyun;LI Lan;CHEN Zhixiong;YU Dengmin;LIU Fan(College of Civil Engineering,Fuzhou University,Fuzhou 350108,China;Fujian Rongsheng Municipal Engineering Co.,Ltd.,Fuzhou 350116,China)

机构地区：[1]福州大学土木工程学院,福建福州350108 [2]福建省榕圣市政工程股份有限公司,福建福州350116

出　　处：《桥梁建设》2023年第5期58-65,共8页Bridge Construction

基　　金：国家自然科学基金项目(51578161);四川省交通科技项目(2020-A-05);天津大学-福州大学自主创新基金合作项目(TF2022-8)。

摘　　要：为增强整体桥的桥台适应主梁温度胀缩变形的能力,减小台后土压力、降低台后填土对全桥结构的约束作用,提出一种新型柔性桥台整体桥梁结构,即在薄壁整体式桥台后设置弹性可压缩材料(EPS)与轻质泡沫混凝土,代替部分台后填土。为研究该新型柔性桥台整体桥的受力性能,以深圳马峦山桥(原型桥)为背景,进行新型柔性桥台整体桥的试设计(试设计桥),建立原型桥与试设计桥有限元模型,进行设计计算和结构验算,比较试设计桥与原型桥在荷载作用下的受力性能和自振特性。结果表明:由于全桥结构的边界约束作用下降,试设计桥的0、3号桥台梁端恒载负弯矩分别比原型桥下降了21.94%、26.28%,活载负弯矩分别下降了16.54%、17.26%,可以有效缓解梁端负弯矩引起的混凝土开裂问题;整体升温或整体降温作用下,试设计桥桥台纵向位移增大了59.85%~63.12%,弯矩与应力分别降低了66.18%~66.73%、31.18%~32.11%;恒、活载作用下,试设计桥跨中和墩顶的弯矩变化并不显著,变化幅度均未超过6%;试设计桥的前10阶自振频率均小于原型桥,可明显减小地震荷载作用下产生的结构内力。A new type of integral bridge with flexible abutments is proposed,which can better accommodate the thermal expansion and contraction deformation of main girder,reduce soil pressure behind the thin-walled integral abutments and mitigate the restraint of backfill to the overall bridge.In this type of the bridge,part of backfill behind the wing walls is replaced by expanded polystyrene(EPS)geofoam and lightweight foam concrete.The Maluanshan Bridge in Shenzhen is taken as the prototype bridge to study the mechanical property of the flexible abutment integral bridge,and based on which a trial-design bridge was designed.The finite element models of the prototype and trial bridges were built up to verify the design calculation and bridge structures,and compare the mechanical properties and natural vibration characteristics of the prototype and trial bridges under loads.It is shown that due to the weakening of the boundary constraints of the overall bridge structures,in the trial-design bridge,the absolute values of hogging moments at the two girder ends under dead loads are reduced by 21.94% and 26.28%,respectively,while the absolute values of hogging moments at the two girder ends under live loads are reduced by 16.54%and 17.26%,respectively,on the basis of the original bridge,which means the bridge is more capable of addressing the concrete cracking induced by girder-end hogging moments.Under the action of overall temperature rise and fall,the longitudinal displacement of the main girder at the abutments of the trial bridge is intensified by 59.85%to 63.12%,and the bending moment and stress have been reduced by 66.18%to 66.73% and 31.18%to 32.11%,respectively.Under both live and dead loads,no significant variation of midspan and pier-top bending moments was observed,with a fluctuation less than 6%.The natural vibration frequencies of first 10 modes of the trial bridge are smaller than those of the original bridge,which is favorable to accommodate the internal forces imposed on the bridge under seismic and other loads

关 键 词：整体桥 柔性桥台 试设计 受力性能 弯矩 应力 变形 自振特性 

分 类 号：U441.5[建筑科学—桥梁与隧道工程]