装配式UHPC桥梁湿接缝模型试验及受弯性能研究

为了改善装配式UHPC(超高性能混凝土)桥梁接缝处由于钢纤维不连续易开裂受损的问题,提出UHPC湿接缝方案并进行优化及受力性能研究。完成了6个试验模型,即直接缝、菱形接缝、上下条带接缝、未焊接及焊接的上下条带菱形接缝5种UHPC接缝梁及UHPC完整梁。对模型的受弯裂缝破坏形式、试验梁的荷载-位移曲线、极限抗弯承载能力、搭接钢筋是否焊接的影响等方面开展相关研究。研究表明:接缝梁的受弯性能均低于完整梁,接缝梁中,焊接的上下条带菱形接缝梁的刚度最高,抗裂缝发展性能最强,综合受弯性能最优,其次是未焊接上下条带菱形接缝梁、上下条带接缝梁、菱形接缝梁和直接缝梁。

Experimental Model Test and Flexural Performance of Wet Joints in Prefabricated UHPC Bridges

In order to improve the performance of the joints in prefabricated UHPC(Ultra-high performance concrete)bridges,several UHPC wet joint structures are proposed for an optimization study on their mechanical performances.In this paper,six experimental models,including vertical joint,rhombus joint,vertical joint with upper and lower strips,unwelded rhombus joint with upper and lower strips and welded rhombus joint with upper and lower strips,and a complete beam,are proposed.Their failure modes,welding effects,ultimate flexural capacities,and the load-displacement curves of the test beams are investigated.The test results show that the mechanical performance of the joint beams is lower than that of the complete beam.Among the four joint wet structures,welded rhombus joint with upper and lower strips has the highest stiffness,the strongest cracking resistance capacity,and the best comprehensive flexural performance.The next followed is the unwelded rhombus joint with upper and lower strips,vertical joint with upper and lower strips,rhombus joint,and vertical joint..