【作者】 吴会军；

【导师】 张哲；

【作者基本信息】 大连理工大学 ， 桥梁与隧道工程， 2005， 硕士

【摘要】 自锚式悬索桥以其优美的造型和对地形地质适应性强等种种优点越来越受到工程界的青睐,尤其是在城市中小跨径桥梁中更是一种极具竞争力的方案。抚顺万新大桥是目前世界上跨径最大的混凝土自锚式悬索桥,并首次采用钢丝绳主缆环形绕过锚固体,故本桥的施工控制存在跨度大、拉力大、变形大、允许误差小等特点和难点。本文结合万新大桥的施工控制,研究了自锚式悬索桥施工控制的理论与方法。主要内容如下: (1) 研究了自锚式悬索桥的计算理论和方法,包括最初的弹性理论到现在的有限位移理论,分析了锚固区环形主缆的平面简化计算。自锚式悬索桥的主缆受力图可简化为承受沿弧长均布荷载加吊索处集中力的柔性索,故主缆视为分段悬链线比抛物线更为精确,采用分段悬链线理论计算了成桥主缆线形,推算了主缆的索股无应力长度、吊索长度、空缆状态线形及索鞍偏移量,确定了索夹的安装位置,采用无猫道架设主缆方案,节省了施工费用且提前了工期,主缆架设过程中考虑了索长变化、温度变化等误差因素对主缆架设线形的影响,施工精度进一步提高。 (2) 由于结构承载力等多种条件限制,自锚式悬索桥的吊索必须经过多次逐步张拉才能达到设计值,本文考虑了吊索张拉过程中混凝土收缩徐变、主缆弹性模量的变化等多种非线性因素的影响,针对吊杆张拉这一复杂的非线性过程,利用有限元程序,研究了在结构承载力和张拉设备能力等约束条件下,吊索反复张拉次数和接长杆数量的计算以及脱模状态的确定方法,理论上可以通过三轮张拉达到满足要求的实际脱模状态,四轮张拉可以达到理想的脱模状态。 (3) 吊杆张拉过程中对塔顶位移、塔底应力、主梁控制截面的内力位移及主缆线形、吊杆力的大小等影响结构安全的因素实施了即时观察测量,每张拉完一遍都及时测量数据并与计算值进行比较分析,调整下一轮的张拉方案并指导下一轮张拉。实际中经过六轮张拉(部分吊索只需张拉两到三轮)达到脱模要求,但索力不太均匀,通过以最小二乘法为基础的有限元程序给出了不均匀索力误差的调整方案,最终成功解决了自锚式悬索桥施工控制中体系转换这一关键问题,本张拉方案只需四台千斤顶同时对称张拉,张拉次数少,且吊索接长杆数量少,张拉效率高,对同类桥型的施工控制有重要的参考价值。更多还原

【Abstract】 Self-anchored suspension bridges are increasingly appreciated by engineers for their merits such as aesthetic appearance and high adaptability to the land form and geology. It has become a more competitive design scheme in middle-, and small-span in cities. Fushun Wanxin Bridge has the largest span in concrete self-anchored suspension bridges in the world at present. It first adopts annular steel rope main cable to wind the anchorage, so the construction control has the following feature and difficulty: large span, large force, large deformation and small permissible error. Based on Wanxin Bridge construction control, this paper studies the theory and method of self-anchored suspension bridge construction control. The main content covers the following aspects:(1) This paper studies the calculation theory and method, including initial elastic theory and finite displacement theory at present. It analyses the plane simplified calculation of the annular main cable anchorage. Main cable force figure can be simplified as flexible cable with even load and focus force at the hanger, so main cable is more precise seen as segmental catenary than seen as parabola. Main cable configuration of completed bridge is calculated by segmental catenary theory, and the free length of each main cable, the hanger length, free main cable configuration, the saddle p re-offset are also calculated, and the position of each rope clip is determined. No passage is adopt in main cable construction. So money and time is in advance. The influence of error factors such as cable length change, temperature change to the main cable erection configuration, so the precision is much higher.(2) Hanger of self-anchored suspension bridges must be stretched many times because of many factors such as load-bearing of structure. For the complicated nonlinear process of tensioning hangers, considering many nonlinear factors, such as the concrete shrinkage and creep, Young’s modulus of main cable ,making use of the finite element program, the method of calculating the times of repetition of tension and the number of extension bars and the method of determining the state of the removing framework are studied under the constraint condition of the bearing c apacity of the structure and the c apacity o f the tensioning machine. Three times can attain the satisfying state of removing framework away and four times of tension can attain the ideal state of removing the framework away in theory.(3) The saddle displacement on the top of the tower, the stress of the tower bottom and the main girder control section, the main cable configuration and the hanger force are observed and measured, and all the data should be analyzed and compared with the calculation data after every tension in order to guide the next tension. Six times later(some hangers only two to three times) the framework can be move away but the hanger force is not homogeneous, the method of nonlinear error adjustment based on the least squares method is presented to adjust the hanger force errors. So the key problem of system transition in construction control of self-anchored suspension bridge is solved. This tension scheme is very efficient because of needing only four jacks to tension in-step at the same time, and needs few extension bar. It has some important reference value to the same bridges.更多还原