大宁河特大桥钢-混组合连续梁负弯矩区受力特性模型试验研究

大宁河特大桥桥面系采用16×27m钢-混组合连续梁,由工字钢梁、预制混凝土板、现浇剪力连接键湿接缝和现浇整体化层组成。为研究钢-混组合连续梁负弯矩区的受力特性,进行焊钉和开孔板2种剪力键类型的1∶2大比例模型试验研究。试验结果表明,开孔板连接件能参与结构受力因而具有较高的整体刚度、较大的初裂荷载;焊钉连接件延性较好;2种连接件均有效且试验梁具有相近的极限荷载。综合比选,该桥桥面系采用焊钉连接件方案。

Model Test Study of Mechanical Behavior of Negative Moment Area of Steel and Concrete Continuous Composite Girder of Daning River Bridge

The floor system of Daning River Bridge employs the 16×27 m steel and concrete continuous composite girder made up of the steel I-girders,precast concrete slabs,cast-in-situ wet joints for welded shear studs and cast-in-situ integral floor layer.To study the mechanical behavior of the negative moment area of the composite girder,the 1∶2 large scale model test for two kinds of the shear connectors of the welded studs and perforated plates was carried out.The results of the test show that the perforated plate connectors have high integral rigidity and great initial cracking load because the connectors can participate in the structural load bearing while the shear stud connectors have good ductility.Both the two kinds of the connectors can work well and the tested girder used with the two kinds of the connectors has similar ultimate load capacity,anyhow after comprehensive comparison,the welded shear stud connectors are eventually selected for the floor system of the bridge.