考虑索夹影响的悬索桥主缆线形精细化分析

发布时间：2018-04-11 09:35

本文选题：悬索桥 + 索夹　；参考：《西南交通大学》2017年硕士论文

【摘要】：主缆作为悬索桥结构的重要承力构件,随着悬索桥跨径的增大,其弯曲刚度对主缆线形的影响将愈发凸显;索夹作为悬索桥主缆与吊索的连接及传力构件,现代悬索桥中"销接式"索夹可以将吊索索力分散为索夹长度范围内的分布力。目前,在悬索桥结构的整体计算理论及分析方法中,均将主缆简化为分段悬链线、将吊索与主缆的连接简化为集中力形式,对于主缆直径较大、索夹长度较长的悬索桥结构,上述简化方式可能引起主缆线形及吊索力的计算值偏离结构真实值,可行的优化方法是在有限元计算中考虑主缆弯曲刚度及索夹构件对结构的影响。本文主要通过以下几个方面对主缆线形的计算模式进行分析研究:(1)基于多尺度有限元计算方法,综合考虑索夹螺杆的张拉、索夹与主缆间的界面接触,研究了索夹构件的传力机理,对比分析了索夹长度、索夹倾角、主缆弯曲刚度等对索夹传力机理的影响,并在此基础上提出了 3种可行的索夹传力简化模式。(2)在索夹传力简化模式的基础上总结了 4种主缆线形计算模式,分别以一座主跨218m的自锚式悬索桥和一座主跨600m的地锚式悬索桥为工程依托,详细分析了不同主缆线形计算模式对主缆线形、吊索力及吊索无应力长度的影响。(3)在算例结构的基础上,通过结构再设计,分别拟定7种跨径布置的自锚及地锚式悬索桥结构,重点讨论了主缆弯曲刚度、索夹传力简化模式对不同跨度悬索桥主缆线形及吊索力的影响及影响程度,提出了不同跨度悬索桥的精细化计算模型建议。研究结果表明,索夹范围内的主缆竖向力呈凹抛物线形式分布,主缆弯曲刚度的形成会促进索夹传力路径向索夹端部移动。采用"均布力形式"得到的主缆成桥线形更接近于实际线形,采用"二力杆形式"得到的主缆成桥线形整体高于实际线形。对于自锚式悬索桥,当主缆跨度小于150m时,桥塔至1/4跨范围内的主缆线形计算需要考虑索夹的影响;当主缆跨度在[150m,250m]范围内时,吊索力的计算需要考虑主缆弯曲刚度的影响,且靠近桥塔的主缆线形计算需要考虑索夹的影响;当主缆跨度在[250m,350m]范围内时,主缆线形及吊索力的计算均需要考虑主缆弯曲刚度的影响,且靠近桥塔的主缆线形计算需要考虑索夹的影响;当主缆跨度大于350m时,主缆线形及吊索力的计算仅需考虑主缆弯曲刚度的影响。对于地锚式悬索桥,当主缆跨度小于250m时,靠近桥塔的主缆线形计算需要考虑索夹的影响;当主缆跨度在[250m,500m]范围内时,无需考虑主缆弯曲刚度及索夹的影响;当主缆跨度大于500m时,主缆线形计算需要考虑主缆弯曲刚度的影响。
[Abstract]:As an important bearing member of suspension bridge structure, as the span of suspension bridge increases, the influence of its bending stiffness on the main cable shape will become more prominent, and the cable clip will be used as the connection and force transfer member between the main cable and the slings of the suspension bridge.In the modern suspension bridge, the "pin type" cable clamp can spread the cable force into the distributed force in the cable clip length range.At present, in the whole calculation theory and analysis method of suspension bridge structure, the main cable is simplified as a segmented catenary, and the connection between the sling and the main cable is simplified as a concentrated force form. For the suspension bridge structure with larger main cable diameter and longer cable clip length,The simplified method may cause the calculation value of the main cable shape and the slings force to deviate from the real value of the structure. The feasible optimization method is to consider the influence of the bending stiffness of the main cable and the cable clamping member on the structure in the finite element calculation.In this paper, the calculation model of the main cable shape is analyzed and studied in the following aspects: 1) based on the multi-scale finite element method, the tension of the cable clip screw and the interface contact between the cable clip and the main cable are considered synthetically.The force transfer mechanism of cable clamp member is studied, and the effects of cable clip length, cable inclination angle and bending stiffness of main cable on the mechanism of cable clamp force transfer are compared and analyzed.On the basis of this, three feasible simplified modes of cable transmission force are put forward. Based on the simplified mode of cable clamp force transfer, four kinds of main cable shape calculation modes are summarized.Based on a self-anchored suspension bridge with a main span of 218m and a ground anchor suspension bridge with a main span of 600m, this paper analyzes in detail the different calculation modes of the main cable line.On the basis of example structure design, seven kinds of self-anchored and ground-anchored suspension bridge structures with span arrangement are worked out, and the bending stiffness of main cable is discussed emphatically.The influence and degree of the simplified mode of cable transfer force on the main cable shape and slings force of different span suspension bridges are discussed. The detailed calculation model of different span suspension bridges is proposed.The results show that the vertical force of the main cable is distributed in the form of concave parabola and the bending stiffness of the main cable will promote the path of the cable to move to the end of the cable clip.The main cable formed by "uniform force distribution" is closer to the actual alignment, and the main cable by "two-force bar" is higher than the actual one.For self-anchored suspension bridges, when the main cable span is less than 150m, the influence of cable clamps should be considered in the calculation of the main cable shape from the tower to 1 / 4 span, and when the main cable span is in the range of [150m ~ 250m], the influence of the bending stiffness of the main cable should be taken into account in the calculation of the sling force.The influence of cable clamp should be considered in the calculation of the main cable shape near the bridge tower, and when the span of the main cable is in the range of [250m ~ 350m], the influence of the bending stiffness of the main cable should be taken into account in the calculation of the main cable shape and the slings force.When the span of the main cable is more than 350 m, the influence of the bending stiffness of the main cable should only be taken into account in the calculation of the main cable shape and slings force.For the ground anchor suspension bridge, when the main cable span is less than 250 m, the influence of cable clip should be considered in the calculation of the main cable shape near the bridge tower, and when the main cable span is in the range of [250 m ~ 500m], the influence of the main cable bending stiffness and cable clamp should not be considered.When the span of the main cable is more than 500 m, the influence of the bending stiffness of the main cable should be considered in the calculation of the main cable shape.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.25

【参考文献】