主缆与鞍座间摩擦抗力评估的混合解析数值法

为保障多塔悬索桥中主塔鞍座的抗滑移安全性，准确评估主缆与鞍座间的摩擦抗力，提出一种适用于鞍座摩擦抗力分析的混合解析数值法。首先，通过分析滑移临界状态下鞍座内索股的受力状态，将主缆与鞍座接触面间摩擦抗力的求解问题逐步分解，最终简化为求解鞍座任意截面处索股与鞍座接触面间压力分布的平面应变问题；其次，沿纵向将鞍座均匀离散化为多个截面，建立相应截面的二维有限元模型，并得出滑移临界状态下各截面处索股与鞍座接触面间的压力分布；采用将各段压力求和再乘以摩擦因数的方式求出主缆与鞍座间的摩擦抗力及其分布，建立适用于主缆与鞍座间摩擦抗力评估的混合解析数值法，并通过模型试验验证其准确性；最后，基于所提出的混合解析数值法对鹦鹉洲长江公路大桥实桥的中主鞍座摩擦抗力进行分析与讨论。研究表明：所提出的混合解析数值法计算结果和试验结果吻合良好，具有计算效率和精度高，评估流程简洁和工程应用便捷等优点，可作为评估主缆与鞍座间摩擦抗力的依据；主缆与鞍座接触面间压力的绝对值和摩擦抗力均呈由上到下、由松边到紧边递增的分布特性；通过设置竖向摩擦板以增加数个竖向摩擦板面，从而有效提高主缆与鞍座间的摩擦抗力，可大幅提高主缆与鞍座间的抗滑移安全性。

Hybrid Analytical-numerical Method for Evaluating the Frictional Resistance Between Main Cable and Saddle

A hybrid analytical-numerical method was proposed to study the characteristic of frictional resistance between main cable and saddle of multi-span suspension bridges, for ensuring their anti-slip safety. Firstly, the problem of analyzing the frictional resistance was decomposed step by step based on the analysis of stress state of the main cable and saddle under critical slipping state; then, it was simplified to a plane strain problem to analyze the pressure distribution between the main cable and saddle in an arbitrary section. Subsequently, the saddle was uniformly divided into several sections along the longitudinal direction, and the corresponding two-dimensional finite element models were established to obtain the normal stress distribution between the main cable and saddle in each chosen section under critical slipping state; then, the frictional resistance and its distribution between the main cable and saddle were obtained by summing the product of the coefficient of friction and the pressure within two adjacent chosen sections. Finally, based on the above evaluation process, a hybrid analytical-numerical method was established to evaluate the characteristic of the frictional resistance between the main cable and saddle; the proposed method was then validated against model experiments. The proposed method possesses high calculation efficiency and accuracy, has a simple evaluation process, and affords engineering application convenience, which can be used to evaluate the frictional resistance between the main cable and saddle. The absolute values of pressure distribution and frictional resistance in the saddle increase gradually from top to bottom and from the loose side to the tight side. The installation of a vertical friction plate can add several vertical friction plate surfaces to improve the frictional resistance between the main cable and saddle effectively, and the anti-slip safety of the saddle can be improved by adding the vertical friction plate.