拉脱法检测夹片锚有效预应力的咬合力模型

拉脱法是检测夹片锚锚下有效预应力的有效方法。为从锚外拉脱曲线获得锚下有效预应力值，首先，分析了桥梁预应力夹片锚固体系的受力特点，探讨了拉脱法曲线产生突降的原因；其次，基于合理的理论假设，通过钢绞线的平衡方程建立了一种通过计算夹片与钢绞线之间摩擦合力的方式获得夹片与锚孔之间咬合力的理论方法；最后，开展了夹片咬合力的室内模型试验，提出了咬合力计算公式，并将理论计算值和试验值进行了对比，结果发现两者结果吻合良好，具有一定的工程应用价值。

Bite Force Model of Effective Prestress of Clip Anchor Detected by Pull-off Method

The pull-off method is an effective method to detect the effective prestress under the clip anchor. In order to obtain the effective prestress value under the anchor from the pull-off curve outside the anchor, the mechanical characteristics of the prestressed clip anchoring system are firstly analyzed, and the causes of the sudden drop of the pull-off curve are discussed. Secondly, based on the reasonable and theoretical assumption and through equilibrium equation, a theoretical method of bite force between the clip and anchor span obtained by calculating the friction force between the clip and the strand is established. Finally, a laboratory model test of the clip bite force is carried out. The calculating formula of the bite force is proposed. The theoretical values are compared with the experimental values. The results show that the both are in good agreement, and have some engineering application values.