斜拉桥桥塔钢-混凝土结合段传力机理试验研究

绵阳城南新区一号桥斜拉桥采用钢-混凝土组合索塔,上钢塔与下混凝土塔之间的内力传递主要是通过承压板、PBL剪力键实现。介绍了钢-混凝土组合索塔在斜拉桥中的应用,分析主塔钢混结合段的受力及构造特点的基础上,采用1∶3缩尺比例,按照几何条件、物理条件以及边界条件相似原则对结合段进行了模型试验。考虑承载能力极限状态荷载组合对试验模型进行加载,测试了试验模型的控制断面和控制构件的应力、变形随加载历程的变化形态,得到了结合段的应力状态、钢与混凝土的相对滑移等性能参数;将模型试验与有限元分析相结合,分析了结合段的传力机理及传力性能,得到结合段PBL剪力键及承压板荷载分配关系。

SPECIMEN TEST FOR MECHANICS BEHAVIOR OF STEEL-CONCRETE COMPOSITE JOINT IN PYLON OF CABLE-STAYED BRIDGE

With a steel-concrete composite joint in pylon,No.1 Bridge is located at the new district south of Mianyang City.Load is transferred between steel and concrete pylon by bearing plate and PBL shear connector.The application of steel-concrete composite pylon in cable-stayed bridge was introduced.The structure characteristics and mechanics behavior of steel-concrete composite pylon were investigated.Based on analogical principle in geometry physics and restriction condition,specimen test of steel-concrete composite joint of the pylon was carried out.With loads exerted according to the ultimate limit state,the stress and deformation of some members of the steel-concrete composite joint were tested.The stress state of steel-concrete composite joint and the slippage between steel and concrete member were obtained.Combining theoretical analysis with the result obtained from the model test,the mechanics behavior of the steel-concrete composite joint was analyzed and the load distribution between PBL shear connector and bearing plate were obtained.