钢桥面-薄层CRRPC组合结构栓钉连接件抗剪疲劳性能研究

采用推出试验和弯曲疲劳试验，研究钢桥面板与薄层CRRPC铺装层间栓钉连接件抗剪疲劳性能。基于Von Mises材料破坏准则和双线性本构关系，对 推出试验模型进行有限元分析、静力试验和疲劳试验，得到不同加载比和界面联接方式下的滑移-加载循环次数曲线，以及栓钉连接件抗剪承载力；开展足 尺组合梁弯曲疲劳试验，考察组合桥面系统中栓钉整体抗剪疲劳性能。研究结果表明：加载比是影响栓钉抗剪疲劳寿命关键因素之一，对于推出疲劳试验， 加载比建议取0.4；钢板与CRRPC间的黏结效应是影响疲劳寿命另一重要因素，对于存在黏结效应的推出试件，在0.5的加载比下等效疲劳寿命可以达到92.2 万次，但无黏结时，疲劳寿命仅为16.9万次；控制栓钉间距是提高组合桥面抗剪疲劳性能的有效方式，在等效实桥应力幅下，即使钢板-CRRPC间不存在黏结 效应，栓钉布距为125mm×125mm，经过8888.9万次疲劳加载，组合梁界面仍没有发生疲劳破坏。

Research on shear fatigue of studs for composite deck system of steel slab and thin CRRPC layer

In order to study the shear fatigue performance of studs used in the composite deck system of steel slab and thin CRRPC pavement, the push-out test and flexural fatigue test were carried out. Based on the Von Mises failure criterion and the bilinear constitutive relation，the slippage-load cycles curves and the shear capacity of studs under different load ratios and different connection modes of interfaces were obtained from finite element analysis, static test and fatigue test of push-out model. Furthermore, the flexural fatigue tests on full-scale composite beam were designed to investigate the shear fatigue performances of studs in composite deck systems.  Results indicate that load ratio is one of key factors influencing the shear fatigue life, and it is recommended that the load ratio be taken as 0.4 for the push-out fatigue test. On the other hand, the bonding effects between steel slab and CRRPC layer is another key factor influencing the fatigue life. For the specimens with bonding effects, the equivalent fatigue life shall be 922 thousand times at the load ratio of 0.4, while for the specimens without bonding effects, the fatigue life shall only be 169 thousand times. In addition, the control of stud spacing is an effective method to increase shear fatigue life of the composite deck. Under the equivalent stress amplitude of Dongting bridge, fatigue failure didn’t occur in the composite beam even without the bonding effects after 88.889 million times of fatigue loading, provided that studs were arranged to be 125mm×125mm.