混凝土收缩徐变效应对曲线钢-混凝土箱形结合梁桥的影响  

Effect of shrinkage and creep of concrete on curved steel-concrete composite box girder bridges

作　　者：雷自学[1] 晏兴威[1] 董三升[1] 

机构地区：[1]长安大学建筑工程学院,陕西西安710061

出　　处：《长安大学学报（自然科学版）》2008年第5期77-80,共4页Journal of Chang’an University(Natural Science Edition)

基　　金：云南省交通科技项目(TST2002204A)

摘　　要：为了研究混凝土收缩徐变效应对曲线钢-混凝土结合箱形梁桥的影响,采用Sap2000商用软件,分析了一实桥结构,在三维建模时分别以壳单元、弹簧单元、梁单元和筋单元等模拟钢箱、钢箱与桥面板之间的剪力连接键、外横隔梁和预应力钢筋等,以多层混凝土壳单元模拟了桥面板,并对施工过程进行了仿真模拟。分析结果表明:混凝土收缩徐变大大增加了桥梁的挠度,不但使跨中正弯矩区混凝板的压应力不断增大,也使负弯矩区混凝土板的压应力不断增大,这一效应对防止负弯矩区混凝土板的开裂是有利的;混凝土桥面板中的普通钢筋对收缩和徐变效应有明显的影响,设计时应认真加以考虑;收缩徐变效应持续时间较长,计算时其作用时间宜取10年以上;另外,曲线梁桥收缩徐变效应也伴随着扭转效应。In order to study the effect of shrinkage and creep of concrete on the curved steel- concrete composite box girder bridges, commercial software Sap2000 was used to analyze a real bridge structure. In three-dimension modeling, elements of shells, springs, beams and tendons were adopted to simulate steel box girders, interfaces between the steel box girders and concrete deck, external diaphragms and prestressing tendons, etc. respectively, and multi-layered concrete shell elements were used to simulate the concrete deck, with the staged construction simulated as well. The analytical results indicate that： the shrinkage and creep of concrete increase the deflection of the bridge significantly, and at the same time lead to a gradual increase not only in the compressive stresses of concrete deck in positive bending moment zones, but also in negative bending moment zones, which is beneficial to the prevention of cracking in the negative bending moment zones; the ordinary reinforcement in the concrete deck has a marked influence on the effect shrinkage and creep, and should be considered carefully in a design; furthermore, the shrinkage and creep has a long lasting effect and their acting time considered in design should be at least ten years. It is further pointed out that the effect of shrinkage and creep is accompanied by torsional effect. 1 tab, 5 figs, 12 refs.

关 键 词：桥梁工程 收缩徐变 结合箱形桥梁 曲线桥 壳单元 普通钢筋 

分 类 号：U444.01[建筑科学—桥梁与隧道工程]