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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。
Aimed at the mechanical characteristics of the prefabricated bridge deck in the composite girder bridge at the wet seams and the connection form of the rebar existing in the seams, a new type of curved steel bar connecting structure with simple structure and convenient construction is proposed. In order to test the mechanical properties of this kind of connection structure, the full-scale tensile test was carried out and compared with the existing mechanical properties of straight bar connection and U-bar connection, Seam cracking load, the ultimate load, crack distribution. The results show that the connection between curved steel bars and straight bars and that of U-shaped bars are the same, the first is that there are cracks on the interface between wet and dry concrete, and the three kinds of wet joints And the corresponding cracking loads are basically the same. With the increase of the load, the new cracks increase one after another, and finally reach the tension limit state, the wet joints near the interface of the three types of steel bars are all yielding near the interface of the wet and dry concrete, At this moment, the strain of the middle part of the joint is 1/2 of the strain at the interface, and the tensile ultimate bearing capacity of the wet joint of the arc-shaped reinforcement is slightly higher than that of the other two. Theoretically, The wet joints in the form of reinforced bars are more evenly distributed in the thickness direction and can increase the bearing capacity to a certain extent. The tests also confirm the wetness of the connection of the curved reinforcing bars in controlling the crack width of the concrete and the bearing capacity of the specimen Seams slightly better than the other two connections, so the connection of curved ribs in the actual project is feasible and reliable.