梁桁组合结构高铁斜拉桥的收缩徐变分析——以西十高铁汉江特大桥为例  

Analysis of Shrinkage and Creep on High-speed Railway Cable-stayed Bridge With Beam-truss Composite Structure—Take the Hanjiang River Super Major Bridge of the Xi'an-Shiyan High-speed Railway as an Example

作　　者：徐斌[1] 卢皓[1] 张浩[1] XU Bin;LU Hao;ZHANG Hao(China Railway First Survey and Design Institute Group Co.,Ltd.,Xi'an 710043,China)

机构地区：[1]中铁第一勘察设计院集团有限公司,西安710043

出　　处：《铁道标准设计》2024年第5期60-67,共8页Railway Standard Design

基　　金：中国铁建股份有限公司科技研发项目(2021-C50);中铁第一勘察设计院集团有限公司科研开发项目(20-35,2021KY59YB-13)。

摘　　要：梁桁组合结构高铁斜拉桥中,混凝土收缩徐变对桥面线性的平顺性及行车的舒适性有直接影响,是桥上能够铺设无砟轨道的关键因素。因此,为分析收缩徐变对梁桁组合结构受力和变形的影响,依托新建西安至十堰高铁汉江特大桥工程,采用CEB-FIP90徐变计算模型,通过建立有限元模型分析收缩徐变影响下主要构件的内力和变形,评价各主要受力构件刚度变化对徐变变形的贡献程度,研究改善收缩徐变变形措施。结果表明:(1)收缩徐变引起主梁跨中下挠、桥塔向跨中侧偏移,同时引起主梁和桥塔的压缩变形,5年完成的收缩徐变变形占前10年的70%以上,且主梁产生的收缩徐变贡献超过50%;(2)收缩徐变引起斜拉索索力松弛,运营30年的最大变化率在5%以内;(3)收缩徐变引起主梁应力及上下缘应力差变化,随着运营时间增加主梁跨中区域应力差增大明显,主要表现在下缘压应力储备降低;(4)随着桥塔刚度、主梁刚度、加劲钢桁刚度增大,收缩徐变引起的变形有所减小,而斜拉索刚度则产生相反的趋势。(5)延长铺轨时间、适当增加底板钢束面积、增加斜拉索索力以及在跨中加劲钢桁上弦灌注混凝土可有效降低主梁跨中徐变下挠。The shrinkage and creep of concrete have direct influence on the linear comfort of the bridge deck and the comfort of driving,which is the key factor for laying ballastless track in this structure.Therefore,in order to analyze the influence of shrinkage and creep on Beam-truss composite structure,the CEB-FIP90 creep calculation model is used to calculate force and deformation of main structural members by finite element method based on Hanjiang River Super Major Bridge on Xi'an-Wuhan High-speed Railway.Contribution degree on creep deformation of stiffness variation from different structural member are evaluated.Measures for improving shrinkage and creep deformation are studied.The results show that:(1)Shrinkage and creep causes down deflection of the main beam and the inclination of the tower to the main-span,as well as compression deformation of the main beam and the tower.Five yearsproportion of shrinkage and creep deformation excess over 70%of ten years’,its contribution from the main beam exceeds 50%.(2)Shrinkage and creep causes unloading of the stay cables,the rate of change is within 5%over 30 years.(3)Shrinkage and creep causes variation of the stress and the stress difference between the upper edge and the bottom edge.The stress difference near middle span is increased with time.(4)With the increase of tower stiffness and beam stiffness as well as steel truss stiffness,shrinkage and creep deformation decrease.In contrast,the reverse trend is found for stay cables.(5)By extending the time between closure of the main span and track laying,appropriately increasing the steel beam area of the bottom plate,increasing the cable force of the stay cable or filling concrete to upper chord of steel truss,the shrinkage and creep deformation of the main beam can be reduced.

关 键 词：高速铁路 斜拉桥 梁桁组合结构 有限元分析 收缩徐变 徐变计算模型 刚度 

分 类 号：U238[交通运输工程—道路与铁道工程] U24[建筑科学—桥梁与隧道工程] U448.27