脱黏对桁架式钢管混凝土拱桥受力性能的影响

Influences of Debonding on Mechanical Behavior of Trussed Concrete-filled Steel Tubular Arch Bridge

采用平面应变理论推导了轴向压力、温度荷载、收缩应变作用下钢管和核心混凝土界面拉应力的计算公式;提出了钢管混凝土拱桥完全脱黏的计算模型,分析了脱黏对桁架式钢管混凝土拱桥内力、刚度和面内极限承载力的影响;提出了采用内法兰构造在有限点限制钢管与核心混凝土相对滑移的脱黏对策,并以茅草街大桥实测数据对内法兰构造的有效性进行了验证。结果表明:脱黏使桁架式钢管混凝土拱桥钢管内力增大,结构刚度降低,面内极限承载力下降;在有限点设置内法兰构造使得脱黏之后桁架式钢管混凝土拱桥的受力性能与黏结良好时比较接近。

Authors deduced formulas for calculating the interface tensile stress between steel tube and core concrete under axial pressure, temperature load and shrinkage strain; proposed complete debonding calculation model of CFST arch bridge; analyzed influences of debonding on internal force, stiffness and ultimate bearing capacity in plane of trussed CFST arch bridge. Authors also proposed debonding countermeasure of adopting inner flange structure to limit the relative slide between the steel tube and core concrete in some points; verified effectiveness of inner flange structure by actual measure data of Maocaojie Bridge. The results show that by occasion of debonding, internal force of steel tube increases; structure stiffness and ultimate bearing capacity decrease; mechanical behavior of trussed CFST bridge with debonding countermeasure is close to that without debonding countermeasure.