外露型钢锚箱组合索塔锚固区水平传力机理

HORIZONTAL LOAD TRANSFER MECHANISM OF COMPOSITE CABLE TOWER ANCHORAGE ZONE WITH EXPOSED STEEL ANCHOR BOX

  • 摘要: 为揭示外露型钢锚箱组合索塔锚固区水平传力机理,基于弹性介质层法推导钢锚箱壁板-混凝土塔壁结合面滑移的理论计算式,进而得到连接件剪力流、钢与混凝土构件轴力的计算方法。通过平截面假定、理论计算式与锚固区节段模型试验结果的比较,验证理论计算式合理性并进行参数化影响分析。研究结果表明:顺桥向预应力和水平索力同时作用时,钢混结合面最大相对滑移0.055 mm,焊钉连接件最大剪力15.99 kN,钢锚箱侧壁板受拉应力6.55 MPa,混凝土塔壁受压应力−1.07 MPa;钢锚箱侧壁板、混凝土塔壁承担顺桥向预应力的比例为10%和90%,水平索力的比例为26%和74%;锚固区水平传力机理受钢锚箱侧壁板厚度、混凝土塔壁厚度、结合面传力长度、连接件抗剪刚度与顺桥向预应力作用的影响很大。

     

    Abstract: In order to reveal the horizontal load transfer mechanism in the composite cable tower anchorage zone with exposed steel anchor box, a theoretical calculation formula for the relative slip between steel anchor box side plate and concrete tower wall is derived upon the elastic medium layer method, and then the calculation methods of shear flow of connectors and axial forces of steel and concrete members are obtained. Through the comparison of plane section assumptions, theoretical calculation formulae and segment model test results of anchorage zone, the rationality of theoretical calculation formulae proposed is verified, and parametric influence analysis is carried out. The results show that: the maximum relative slip of the steel-concrete interface is 0.055 mm, the maximum shear force of the stud connectors is 15.99 kN, the tensile stress of the steel anchor box side plate is 6.55 MPa, and the compressive stress of the concrete tower wall is −1.07 MPa. The proportion of prestress along the bridge direction between steel anchor box side plate and concrete tower wall is 10% and 90%, and the proportion of horizontal cable force is 26% and 74%. The horizontal force transfer mechanism of anchorage zone is greatly influenced by the thickness of steel anchor box side plate, by the thickness of concrete tower wall, by the force transfer length of steel-concrete interface, by the shear stiffness of connectors and, by the prestress along the bridge direction.

     

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