装配式桥梁板玻璃纤维混凝土-U形钢筋湿接缝受力与变形分析

Analysis of Load Bearing Behavior and Deformation of Cast-in-Situ Stitches with Glass Fiber Reinforced Concrete and U Reinforcement Among Deck Panels of Precast Segmental Bridge

为解决装配式桥梁板体系湿接缝处力学性能不稳定、易变形的问题,提出采用玻璃纤维混凝土-U形钢筋加强方案优化湿接缝性能,以雄安新区荣乌高速荣乌主线桥为背景进行研究。选取主线桥2个试验段(试验段A湿接缝采用普通混凝土-U形钢筋方案,钢筋点焊;试验段B湿接缝采用玻璃纤维混凝土-U形钢筋加强方案,钢筋满焊)进行梁板体系湿接缝性能试验,监测湿接缝处搭接钢筋力学响应及混凝土接触面变形特征,同时对长期运载及强降雨影响下的钢筋受力与混凝土变形进行监测。结果表明:长期运载下,试验段B横筋受力约为试验段A的一半,其中部纵筋承受外力远大于试验段A,边缘纵筋承受外力较少,试验段B稳定性更优;试验段B较试验段A在湿接缝部位变形量小,其稳定性及耐久性更优;强降雨阶段,试验段B较试验段A变形及力学响应波动程度更低,其抗渗能力、耐久性更优。由此可知基于玻璃纤维混凝土-U形钢筋加强方案的湿接缝构造在外力传导、抵抗变形方面具有较强稳定性,不易受恶劣环境影响。

A method of using glass fiber reinforced concrete and U reinforcement to optimize the cast-in-situ stitches among deck panels of the precast segmental bridge is proposed,aiming to ensure the load bearing stability and reduce deformation of the stitches.A mainline viaduct of Rongcheng-Wuhai Expressway in Xiong′an New Area is used as a case for the study.Two test sections were taken from the viaduct to investigate the performance of the cast-in-situ stitches among deck panels,test section A contains cast-in-situ stitches with normal concrete and spot-welded reinforcement,and test section B incorporates cast-in-situ stitches of glass fiber reinforced concrete and all-welded U reinforcement.The monitoring focuses included the mechanical responses of the lapped reinforcement in cast-in-situ stitches and deformation characteristics of concrete contacting faces,as well as the load bearing capacity of reinforcement and concrete deformation under long-term vehicle loads and heavy rains.It is shown that under long-term vehicle loads,the load bearing behaviors of transverse reinforcement in test section B is half of that of the section A,and the reinforcement in the central zone bears greater loads than the edge reinforcement,and also greater loads than that in the central zone of test section A,indicating the stability of test section B is superior to test section A.In addition,the deformation of cast-in-situ stitches in test section B is smaller,indicating better stability and durability.Under heavy rains,the deformation and fluctuation of mechanical responses of test section B are lower,displaying better impermeability and durability.It is proved that the cast-in-situ stitches with glass fiber reinforced concrete and U reinforcement own sound external force transfer and deformation resistant stability,and are not sensitive to harsh environments.