多塔自锚式悬索桥缆索系统施工过程分析研究

发布时间：2018-11-10 11:44

【摘要】：多塔自锚式悬索桥施工控制的核心工序为空缆架设和吊索张拉,空缆架设期间因塔梁系统和缆索系统施工偏差以及施工期环境温度的影响,空缆目标线形发生变化。空缆线形的精确性将直接影响成桥主缆线形,必要时应采用调整索股张力的方法进行空缆线形调整。不同于地锚式悬索桥采用的主梁吊装工艺,自锚式悬索桥吊索张拉过程主梁刚度已经形成,且主梁多支撑于支架上,吊索力不可能一次张拉到设计索力,必须进行往复张拉。吊索张拉过程伴随索鞍顶推,塔梁系统和缆索系统高度耦合,分析控制复杂。在制定合理的张拉方案时,应综合考虑施工安全性和经济性,对张拉过程桥塔、主梁、吊索应力状态及千斤顶数量、接长杆数量等多目标因素进行综合比选。本文采用有限元方法进行自锚式悬索桥合理成桥状态确定,计算结果与设计吻合较好。其中主缆线形最大偏差15mm;吊索力最大偏差3%;主缆无应力长度偏差4cm,为主缆无应力索长的万分之0.8;吊索无应力索长最大偏差11mm。对自锚式悬索桥空缆架设期间缆索系统、支撑系统及环境温度作用下,空缆线形的敏感性进行了细致的分析,结构升降温、主索鞍竖向施工偏差、散索鞍竖向施工偏差、锚面竖向及纵向施工偏差对空缆线形较为敏感。给出了各因素对空缆边中跨垂点变形的影响系数,提出快速查表方法对空缆目标线形的修正计算,并给出算例验证。给出了空缆线形调整时各跨无应力长度调整量,方便空缆线形调整。综合施工期吊索应力状态、桥塔及主梁应力状态,千斤顶数量、接长杆数量及规格、主缆和索鞍的相对几何位置确定采用临时压重从跨中-桥塔张拉吊索为最优张拉方案。针对最优张拉方案,对吊索张拉过程桥塔应力及塔顶偏位、主缆变形、索鞍与主缆接触状态以及施工期吊索力变化进行了细致分析,分析表明本文推荐方案满足各项控制要求。本文研究对于多塔自锚式悬索桥缆索系统施工过程控制分析具有重要的借鉴和参考意义。
[Abstract]:The core process of construction control of multi-tower self-anchored suspension bridge is aerial cable erection and sling tension. During aerial cable erection, the alignment of aerial cable object changes due to the construction deviation of tower and cable system and environmental temperature during construction. The accuracy of the cable shape will directly affect the main cable shape of the bridge. If necessary, the method of adjusting the cable tension should be adopted to adjust the cable shape. Different from the main beam hoisting technology adopted by ground anchor suspension bridge, the stiffness of the main beam has been formed during the stretching process of the suspension cable of the self-anchored suspension bridge, and the main beam is more supported on the support, the sling force cannot be pulled to the design cable force at one time, and the reciprocating tension must be carried out. The cable tension process is accompanied by the saddle pushing, the tower and beam systems are highly coupled with the cable system, and the analysis and control are complicated. When drawing up a reasonable tensioning scheme, the safety and economy of construction should be considered synthetically, and the multi-objective factors such as bridge tower, main beam, slings stress state, the number of Jack and the number of connecting rod should be comprehensively compared and selected. In this paper, the finite element method is used to determine the reasonable state of self-anchored suspension bridge. The calculated results are in good agreement with the design. The maximum deviation of main cable shape is 15mm; the maximum deviation of sling force is 3; the deviation of main cable's unstressed length is 4 cm, and the length of main cable's unstressed cable is 0.8%; the maximum deviation of sling's unstressed cable length is 11mm. In this paper, the sensitivity of cable system, support system and ambient temperature during the erection of aerial cable of self-anchored suspension bridge is analyzed in detail, the structure rises and cools, the vertical construction deviation of main cable saddle and the vertical construction deviation of loose cable saddle are analyzed. The vertical and longitudinal construction deviations of anchor face are sensitive to the aerial cable shape. The influence coefficients of various factors on the vertical deformation of midspan in the side of aerial cable are given, and the modified calculation of aerial cable target alignment by fast table checking method is put forward, and an example is given to verify the effect of these factors on the vertical deformation of aerial cable. The adjustment amount of each span's stress-free length during the adjustment of aerial cable shape is given, which is convenient for the adjustment of aerial cable shape. According to the stress state of sling during construction, the stress state of bridge tower and main beam, the number of Jack, the number and specification of connecting rod, and the relative geometric position of main cable and cable saddle, the optimum tension scheme is determined to be temporary compression weight from the mid-span to the bridge tower. Aiming at the optimal tensioning scheme, the stress of the tower, the deflection of the tower top, the deformation of the main cable, the contact state of the cable saddle with the main cable and the change of the cable force during the construction period are analyzed in detail. The analysis shows that the scheme recommended in this paper meets the control requirements. The research in this paper has important reference and reference significance for the construction process control analysis of cable system of multi-tower self-anchored suspension bridge.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U445.4;U448.25

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