钢板梁桥U形钢筋湿接缝力学性能试验研究

Experimental Study on Mechanical Properties of U-Shaped Steel Bar Wet Joint of Steel Plate Girder Bridge

U形钢筋湿接缝是一种具有良好受力并能适应桥梁快速施工的接缝形式。针对中小跨径钢混组合梁桥墩顶负弯矩区域处横向U形湿接缝处于受拉状态,混凝土可能开裂的特点,设计制作3组U形钢筋湿接缝拉伸试件,通过静力拉伸试验分析不同钢筋搭接长度、搭接形式对接缝受力性能及抗裂性能的影响。结果表明:3个试件混凝土开裂区域均在接缝范围内,最先开裂及最大裂缝的位置位于湿接缝与桥面板的施工缝处,设计或施工时应予以关注;U形钢筋采用焊接或增加搭接长度可减小钢筋平均应力,U形钢筋采用交错形式时钢筋平均应力增加约16.8%。

U-shaped steel bar wet joint is a kind of joint with good force and can be suitable to the rapid construction of bridges. In view of the fact that the transverse U-shaped wet joint at the negative moment area of pier top of small and medium span steel-concrete composite girder bridge is in tension state and concrete may crack, three groups of U-shaped steel bar wet joint tensile specimens are designed and manufactured. The effects of different overlap length and overlap form of steel bar on the mechanical properties and crack resistance of the joint are analyzed by static tensile test. The results show that the cracking areas of the three specimens are all within the joint range, the location of the first crack and the largest crack is at the construction joint of wet joint and bridge deck, which should be paid attention to in design or construction;the average stress of the U-shaped steel bar can be reduced by welding or increasing overlap length, and the average stress of the U-shaped steel bar increases by about 16.8% when the U-shaped steel bar is staggered.