公铁合建斜拉桥钢桁-混凝土板组合梁受力特性  

Mechanical characteristics of steel truss-concrete slab composite girder of a railway-cum-road cable-stayed bridge

作　　者：施洲[1] 赵旭泼 刘振标[2] 夏正春[2] 印涛[2] SHI Zhou;ZHAO Xupo;LIU Zhenbiao;XIA Zhengchun;YIN Tao(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Bridge Design&Research Department,China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]中铁第四勘察设计院集团有限公司桥梁设计院,湖北武汉430063

出　　处：《铁道科学与工程学报》2024年第7期2778-2789,共12页Journal of Railway Science and Engineering

基　　金：国铁集团科技研发项目(N2021G034);中铁第四勘察设计院集团有限公司科技研发项目(2021K015)。

摘　　要：以某主跨808 m的公铁合建新型钢桁-混凝土板组合梁斜拉桥为背景,采用ANSYS软件建立局部组合梁细化的全桥多尺度有限元模型,分析其在不同工况下双层组合梁的受力传力特性和混凝土桥面板荷载分配比,并讨论混凝土桥面板厚度t_(b)、横梁刚度变化系数λ_(K)和钢与混凝土弹性模量比λ_(E)对组合梁受力传力的影响规律。结果表明:最不利组合工况下,钢桁架最不利Von Mises应力为183.6 MPa,混凝土桥面板最大拉应力为5.3 MPa,均满足结构受力要求;沿纵向路径,钢桁架和混凝土桥面应力在节间横梁间均呈“波形”分布;上下层混凝土桥面板顶、底面应力沿横向近似呈“W”和“M”状分布,表明桥面板承受一定沿横向不均匀分布弯矩;公路及铁路混凝土桥面最大剪力滞系数分别为1.45、1.36,更宽的公路混凝土桥面剪力滞效应更显著;公路及铁路混凝土桥面分别承担上、下层结构57.46%~79.99%和33.21%~62.81%的轴向荷载,为组合梁的主要传力构件;混凝土桥面板的应力随t_(b)及λ_(K)的增大而增大,随λ_(E)的增大而逐渐减小;混凝土桥面每层平均荷载分配比ξ与t_(b)成正比,与λ_(K)及λ_(E)成反比;当t_(b)、λ_(K)和λ_(E)参数的取值范围分别为0.8~1.4、0.4~1.6以及4~10时,组合梁混凝土桥面应力及荷载分配比ξ较为合理。Taking the rail-cum-road new type steel truss-concrete slab composite girder cable-stayed bridge with a main span of 808 m,Hongqili Grand Bridge,as the background,the multi-scale whole bridge finite element model with fine local composite girder segments was established using ANSYS software.The mechanical properties,force transmission characteristics and load distribution ratio of the double-layer composite girder under different working conditions were analyzed.The influence of the thickness of the concrete bridge deck t_(b),the stiffness variation coefficient of the crossbeamλ_(K) and the elastic modulus ratio of steel and concreteλ_(E) on the stress of the composite girder was discussed.The results show that the most unfavorable Von Mises stress of steel truss is 183.6 MPa and the maximum tensile stress of concrete deck is 5.3 MPa under the most unfavorable working condition.The results can meet the requirements of structural force.Along the longitudinal path,the stresses of steel truss and concrete both wave between the inter-section crossbeams.The stresses on the top and bottom surfaces of both upper and lower concrete decks approximately illustrate the‘W’and‘M’shapes along the transverse direction,indicating that the concrete decks bear a certain un-uniform bending moment along the transverse direction.The maximum shear lag coefficients of highway and railway concrete decks are 1.45 and 1.36,respectively.The shear lag effect of wider highway concrete decks is more significant.The concrete decks of highway and railway bear 57.46%~79.99%and 33.21%~62.81%axial loads of the upper and lower structures respectively,which are the main force transfer components of the composite girder.The stress of the concrete deck increases with the increase of t_(b) andλ_(K) and decreases with the increase ofλ_(E).The average load distribution ratioξof each layer of the concrete deck is proportional to t_(b),and inversely proportional toλ_(K) andλ_(E).When the parameters of t_(b),λ_(K) andλ_(E) are in the range

关 键 词：大跨度公铁合建斜拉桥 钢桁-混凝土板组合梁 受力特性 传力特性 参数分析 

分 类 号：TU398.9[建筑科学—结构工程]