用于组合梁桥面板湿接缝的弧形钢筋连接构造

发布时间：2018-09-01 10:21

【摘要】：针对组合梁桥中预制桥面板在湿接缝处的受力特点和现有接缝处钢筋的连接形式,提出了一种构造简单、施工方便的新型的弧形钢筋连接构造。为了检验这种连接构造的力学性能,对其进行足尺模型的轴心受拉试验,并与现有的直钢筋连接方式和U形钢筋连接方式的力学性能进行试验对比,分析了3种湿接缝的开裂荷载、极限荷载、裂缝分布等。试验结果表明:弧形钢筋连接方式与直钢筋连接方式以及U形钢筋连接方式的湿接缝破坏形式相同,均是首先在干湿混凝土交界面上出现裂缝,3种钢筋连接方式的湿接缝对应的开裂荷载基本相同;随着荷载增加旧裂缝宽度增加、新裂缝相继出现,最后达到受拉极限状态时3种钢筋连接方式的湿接缝都是干湿混凝土交界面附近的钢筋达到屈服,此时接缝中部钢筋的应变为交界面处钢筋应变的1/2,且弧形钢筋连接方式湿接缝的抗拉极限承载力比其他2种略高;理论上在湿接缝区域中弧形钢筋连接方式的湿接缝其钢筋在厚度方向分布更加均匀,能在一定程度上提高承载力,通过试验也证实了在控制混凝土裂缝宽度和试件的承载力方面弧形钢筋连接方式的湿接缝比其他2种连接方式略优,因此弧形筋连接方式运用于实际工程中是可行和可靠的。
[Abstract]:According to the mechanical characteristics of precast deck slab in composite beam bridge at wet joint and the connection form of steel bar in existing joint, a new type of arc-shaped steel bar connection structure with simple structure and convenient construction is put forward. In order to test the mechanical properties of the connection structure, the axial tensile test of the full-scale model is carried out, and the mechanical properties of the connection mode of the straight steel bar and the U-shaped steel bar are tested and compared with those of the existing straight steel bar connection mode and the U-shaped steel bar connection mode. The cracking load, ultimate load and crack distribution of three kinds of wet joints are analyzed. The test results show that the connection mode of arc steel bar is the same as that of straight steel bar and the wet joint failure mode of U-shaped steel bar. The cracking load of the wet joints corresponding to the three kinds of reinforcing bar connections are basically the same, and with the increase of the width of the old cracks, the new cracks appear one after another. Finally, when the tensile limit state is reached, the wet joints of the three kinds of steel bar connections are all the steel bars near the interface of dry and wet concrete to yield. At this time, the strain of steel bar in the middle of the joint is 1 / 2 of the strain of steel bar at the interface, and the ultimate tensile capacity of the wet joint is slightly higher than that of the other two. In theory, the distribution of steel bar in the thickness direction of the wet joint of arc steel bar in the wet joint region is more uniform, which can improve the bearing capacity to a certain extent. The test also proves that the wet joint of arc-shaped steel bar is better than the other two ways in controlling the crack width of concrete and the bearing capacity of the specimen, so it is feasible and reliable to apply the arc-bar connection mode in practical engineering.
【作者单位】：同济大学土木工程学院;
【基金】：国家重点基础研究发展计划(“九七三”计划)项目(2013CB036303)
【分类号】：U443.31

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