钢管混凝土拱桥施工全过程受力行为及稳定性  

Mechanical Behavior and Stability of Concrete⁃filled Steel Tubular Arch Bridge During Whole Construction Process

作　　者：田康 TIAN Kang(Railway Engineering Research Institute,CARS,Beijing 100081,China)

机构地区：[1]中国铁道科学研究院集团有限公司铁道建筑研究所,北京100081

出　　处：《铁道建筑》2023年第10期75-80,共6页Railway Engineering

摘　　要：为探求钢管混凝土拱桥施工过程中需要重点关注的关键环节和部位,分析扣索索力对累计变形的影响,以及钢管和混凝土两种材料各自承担的应力比例和应力变化幅度。以一座中承式钢管混凝土系杆拱桥为例,针对各个施工阶段,采用有限元软件MIDAS/Civil进行结构变形、应力计算及稳定性分析。结果表明:该桥应力及稳定性满足JTG/T D65-06—2015《公路钢管混凝土拱桥设计规范》要求;钢管拱肋的吊装阶段和核心混凝土的灌注阶段,受力复杂,须要严格监测和控制;在拱肋吊装阶段,拱肋的竖向位移随施工推进而逐渐增大,施工过程中应实时监测拱肋线形并适时调整扣索索力,避免累计变形过大(可达到L/800以上,L为跨度);在施工过程中,拱脚截面为较薄弱截面,往往出现最大内力和压应力;钢管应力约为混凝土应力的6倍,且钢管应力变化幅度大于混凝土;各工况下稳定系数均大于规范值4.0,拱肋上弦管混凝土灌注(联合前)阶段更易发生失稳,其一阶模态稳定系数为29.33。In order to find out the key points in the construction process of concrete-filled steel tubular(CFST)arch bridge,the influence of stayed-buckle cable force on cumulative deformation,as well as the stress ratio and stress variation amplitude of steel tubular and concrete were analyzed.Taking a half-through CFST tied arch bridge as an example,the deformation calculation,stress calculation and stability analysis of the structure were carried out by using the finite element software MIDAS/Civil for each construction stage.The results show that the stress and stability of the bridge meet the requirements of JTG/T D65-06—2015 Specifications for Design of Highway Concrete-filled Steel Tubular Arch Bridges.The hoisting stage of steel tubular arch rib and the pouring stage of core concrete are subjected to complex forces and require strict monitoring and control.In the stage of arch rib hoisting,the vertical displacement of arch rib increases gradually with the advance of construction sequence.In the construction process,the arch rib alignment should be monitored in real time and the stayed-buckle cable force should be adjusted in time,otherwise the cumulative deformation will be too large,which can reach more than L/800(L is the span).The arch foot section is weak section,which often appears the maximum internal force and compressive stress.The stress of steel tube is about 6 times that of concrete,and the stress variation amplitude of steel tube is larger than that of concrete.The stability coefficients under different working conditions are all higher than the standard value 4.0,among which the stage of pouring concrete in arch rib upper chord tubes(before working together)is more prone to instability,and its first-order modal stability coefficient is 29.33.

关 键 词：公路桥梁 钢管混凝土拱桥 有限元分析 静力计算 累计变形 稳定性分析 拱肋吊装 

分 类 号：U448.22[建筑科学—桥梁与隧道工程]