悬索桥静载试验主缆索力增量测试方法

发布时间：2019-07-06 11:51

【摘要】：主缆索力增量测试是悬索桥静载试验的主要测试项目之一,但目前悬索桥主缆索力的常用测试方法 (振动法)存在技术要求高、计算复杂等不足,无法较好地应用于桥梁静载试验中的主缆索力增量测试。因此提出一种新的、简便的主缆索力增量间接测试方法。假定主缆、主塔位于同一竖直平面内,通过分析悬索桥塔顶主缆节段受力平衡方程、主塔下横梁以上节段受力平衡方程,可以导出主缆索力与主塔下横梁以上任意截面内力之间的关系,并进一步可得到主缆索力增量与该截面内力增量的关系。根据截面的内力平衡方程及应力应变关系,得到主塔下横梁以上任意截面内力增量与其表面应变增量的关系。再根据塔柱和主缆的几何尺寸、材料特性等其他参数,即可计算出主缆索力的增量。将该方法应用到永康市溪心桥的静载试验中,进行了主缆索力增量的测试,得到了较好的效果。同时结合实例对影响主缆索力增量测试精度的各因素进行了分析,提出应变测试精度、塔柱的材料特性、测试截面面积及塔顶主缆切向与竖直向的夹角对测试结果均有较大的影响,实际使用时应对这些参数做出准确的测量或估计。该方法实施简单、方便,对仪器设备及测试条件要求较低,可为同类桥梁在静载试验中进行主缆索力增量测试提供参考。
文内图片：

图片说明：主缆节段受力分析示意图
[Abstract]:The incremental test of main cable force is one of the main test items of static load test of suspension bridge, but at present, the common testing methods of cable force of suspension bridge (vibration method) have some shortcomings, such as high technical requirements, complex calculation and so on, so they can not be well applied to the incremental test of main cable force in bridge static load test. Therefore, a new and simple indirect test method for the increment of main cable force is proposed. Assuming that the main cable is located in the same vertical plane, the relationship between the cable force of the main cable and the internal force of any section above the beam under the main tower can be derived by analyzing the stress balance equation of the main cable section at the top of the suspension bridge and the stress balance equation above the beam under the main tower, and the relationship between the force increment of the main cable and the internal force increment of the section can be further obtained. According to the internal force balance equation and the stress-strain relationship of the section, the relationship between the internal force increment and the surface strain increment of any section above the beam under the main tower is obtained. According to the geometric size, material characteristics and other parameters of the tower column and the main cable, the increment of the cable force of the main cable can be calculated. This method is applied to the static load test of Xixin Bridge in Yongkang City, and the increment of the cable force of the main cable is tested, and good results are obtained. At the same time, the factors affecting the incremental test accuracy of the main cable force are analyzed with an example, and it is put forward that the strain test accuracy, the material characteristics of the tower column, the test cross section area and the angle between the tangential and vertical directions of the main cable at the top of the tower have great influence on the test results. These parameters should be accurately measured or estimated in practical use. The method is simple and convenient, and the requirements for instruments, equipment and test conditions are low, which can provide a reference for the incremental test of the main cable force of the same kind of bridge in the static load test.
【作者单位】：浙江浙交检测有限公司;
【分类号】：U446;U448.25

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