混凝土桥面板湿接缝纯弯破坏行为试验研究

为了解不同钢筋连接形式下混凝土桥面板湿接缝的抗弯性能,以某高速公路连续梁桥为背景进行研究。设计制作带湿接缝的桥面板试件(1组直钢筋焊接试件、1组直钢筋搭接试件、5组环形钢筋搭接试件),通过纯弯试验研究其裂缝发展、破坏形态、开裂荷载、破坏荷载及混凝土与钢筋应变的变化规律。结果表明:新旧混凝土结合面最先开裂,是整个试件的薄弱面,设计中应加强;不同钢筋连接方式试件的破坏荷载从大到小依次为环形钢筋搭接>直钢筋搭接>直钢筋焊接;环形钢筋搭接试件的承载力随着搭接长度的增加逐渐增加;对于两端有水平约束的桥面板结构,在临界破坏状态时呈现板结构+膜结构的两体系受力状态。

Experimental Study on Pure Bending Failure Behavior of Wet Joint of Concrete Bridge Deck

To compare the flexural behavior of wet joint of concrete bridge deck with different steel bar connections, the research was conducted based on a continuous girder bridge in highway. A series of bridge deck specimens (1 set of specimens with welded straight steel bar, 1 set of specimens with lapped straight steel bar, and 5sets of specimens with lapped ring steel bar) were designed and prepared to perform pure bending tests so as to study the cracking development, failure mode, cracking load, failure load, and change law of strain of concrete and steel bar. The results show that the new-old concrete interface, as a weak site of entire specimen, cracks firstly, thus should be strengthened in design. The failure load of specimens with different steel bar connections varies significantly, and is sequentially in following order: the specimens with lapped ring steel bar > specimens with lapped straight steel bar > specimens with welded straight steel bar. In addition, the loading capacity of the specimen will increase as the lapped length of ring steel bar increases. For concrete bridge deck with horizontal restrains at both ends, two internal forces of slab and membrane structures will occur in a critical failure state.