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为了研究体外预应力节段预制桥梁干接缝键齿的抗剪性能,对3组足尺单键齿干接缝试件分别在初始1,1.5,2 MPa的正应力作用下进行了直剪试验。同时应用有限元分析软件ABAQUS对试验进行了仿真,并进一步建模分析键齿尺寸对干接缝键齿强度的影响。试验结果表明,临近键齿根部配置的钢筋能抑制裂缝的发展,进而提高键齿的抗剪承载力,AASHTO公式低估了这种配筋方式下的单键齿干接缝抗剪承载力。随着正应力的增大,单键齿干接缝的极限剪切承载力小幅度提高,其极限剪切竖向相对滑移也增大。有限元分析结果表明,极限剪切荷载模拟值与实测值吻合良好,模拟的键齿裂纹开展情况与试验相吻合。梯形单键齿干接缝的适宜梯形底脚范围是45°~60°,在此范围内其抗剪强度变化不大。
In order to study the shear resistance of pre-stressed dry joints of prestressed bridges in vitro, the specimens of three groups of full-size single-keyed dry joints were subjected to direct shear with initial force of 1,1.5,2 MPa test. At the same time, the finite element analysis software ABAQUS was used to simulate the experiment, and the influence of the size of the key teeth on the strength of the dry joint was further modeled. The test results show that the reinforcement located near the base of the tooth root can inhibit the development of the crack and improve the shear resistance of the key tooth. The AASHTO formula underestimates the shear strength of the single-tooth dry joint under the reinforcement method. With the increase of normal stress, the ultimate shear bearing capacity of single-tooth tooth dry joint increases slightly, and the relative slip of vertical shear increases also. The results of finite element analysis show that the simulated values of ultimate shear load are in good agreement with the measured values. The simulation of the development of key tooth cracks is in good agreement with the experimental results. Trapezoidal single-tooth dry joint suitable trapezoidal foot range is 45 ° ~ 60 °, in this range of shear strength changes little.