基于安全性的路桥过渡段差异沉降控制标准

Control Criterion of Differential Settlement of Bridge Approach Based on Safety

为研究路桥过渡段差异沉降量化指标,对设搭板和不设搭板2种情况下的路桥过渡段差异沉降建立计算模型。引入动荷载系数作为行车安全性评价指标,将车辆系统简化为5自由度半车模型进行垂直振动的力学模拟,求解分析了车辆通过不同台阶高度(不设搭板情况)和不同搭板长度(设搭板情况)的路桥过渡段动荷载和动载系数的变化规律。结果表明:随着台阶高度增加,前后轮受力最大值逐渐增大,受力最小值逐渐减小;当台阶高度为5 cm时,前后轮受力的最小值已逐渐接近于0,当台阶高度为7 cm时,前后轮受力已出现负值;设置搭板后整车动荷载系数有明显减小,且随着搭板长度增加,整车动荷载系数减小。在此基础上,提出了基于安全性的路桥过渡段差异沉降控制标准。

In order to study the differential settlement quantitative index of bridge approach, 2 calculation models of differential settlement on bridge approach （with and without bridge end transition slab ） are established. Introducing dynamic load coefficient as traffic safety evaluation index, vehicle system is simplified to 5 degrees of freedom half vehicle model for vertical vibration mechanical simulation, the variation regularities of dynamic load and dynamic load coefficient of bridge approach in the case of vehicle passing through different step heights （without bridge end transition slab） and different transition slab lengths （ with bridge end transition slab） are discussed. The results show that （ 1 ） with the increase of step height, the maximum forces of front and rear wheels gradually increase, but the minimum forces decrease gradually ; （2） the minimum forces of front and rear wheels gradually close to zero when the step height is 5 cm, and the forces of wheels change to negative value when the step height is 7 cm ; （3） the dynamic load coefficient of vehicle reduces significantly after setting bridge end transition slab, and the dynamic load coefficient decreases slowly with the increase of transition slab length. On this basis, the control criterion of differential settlement on bridge approach based on safety is proposed.