自锚式悬索桥受力性能研究

【作者】 武隽；

【导师】 周绪红；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2007， 硕士

【摘要】 自锚式悬索桥以其新颖美观,经济效益较好,对地形地质适应性强等优点,在国内得到了快速的发展,成为100～400m跨径范围内极具竞争力的桥梁方案。本文以主跨为328m的三汊矶大桥为工程背景,对自锚式悬索桥的受力性能进行研究。首先,论文对自锚式悬索桥缆索系统计算进行了研究。计算方法主要有不考虑加劲梁的数值计算方法,包括抛物线法和分段悬链线法,以及可以计入加劲梁影响的有限元法。本文对各种方法的理论进行了详细的阐述、推导和比较。根据自锚式悬索桥的特点,应该采用有限元法进行计算以得到理想的结果。然后,本文利用ANSYS的二次开发语言APDL编制了程序SASB,采用有限元法计算三汊矶自锚式悬索桥的缆索系统。通过对大桥的施工过程进行正装迭代计算,考虑了加劲梁刚度对自锚式悬索桥的贡献以及施工工序对线形的影响,计算得到主缆成桥线形、空缆线形、索鞍预偏量和索夹安装位置。结果表明,有限元法和不考虑加劲梁刚度的数值法计算的无应力索长和成桥时主缆水平分力的最大相对误差分别为0.53%和1.96%。其次,本文通过静、动力计算和参数分析对自锚式悬索桥受力性能进行进一步研究。参数分析表明,与地锚式相反,自锚式悬索桥的刚度随矢跨比的减小而减小;自锚式悬索桥吊杆间距与桥梁刚度成非线性关系,偏大或偏小都会使加劲梁刚度降低,应通过比较采用合理的间距;预拱度的设置可以提高结构的刚度。自锚式悬索桥的塔梁纵向阻尼大小对基频有较大的影响,基频随着塔梁间纵向阻尼值的增加而变大。更多还原

【Abstract】 As a novel bridge type, self-anchored suspension bridge develops quickly in China for its advantages in asesthetics, economics and adaptability of geology and topography. It has been a competitive plan for bridge with span from 100m to 400m. Taking Sanchaji Bridge as background, the thesis carried out research on self-anchored suspension bridge.Firstly, it studied computation methods of cable system of self-anchored suspension bridge. The methods can be divided by two categories. One is without considering the girder’s effects on cable system, including parabolic method and segmental cateneries method, and another is finite element method which could consider the girder’s effect. The thesis expounded those methods, deduced a series of formulae and compared them. According to the feature of self-anchored suspension bridge, it is recommended to apply finite element methos to obtain exact results.Next, it calculated the cable system of Sanchaji Bridge through finite element method by compiling SASB program using APDL, parametric language of finite element program ANSYS. Through iteration computing of orderly-erecting analysis, it calculated cable in bridge completion stage, cable finished stage, excursion of saddles and the installing position of hangers considering the influence of girder and construction process. The result showed that there were about 0.53% and 1.96% deviations in zero-stress length and horizontal force of cable between method without considering girder’s stiffness and finite element method.Finally, it carried out static and dynamic computation and parametric analysis to research mechanical behavior of self-anchored suspension bridge. The results showed that the stiffness of self-anchored suspension bridge would decrease with the decreasement of rise-span ratio while earth-anchored suspension bridge has the opposite behavior. And the distance between hangers had nonlinear effect on bridge’s stiffness as being too long or too short would reduce structure’s rigidity, so it need comparation to determine the optimal distance between hangers. In addition, the set of girder camber could increase structure’s rigidity. Besides, the longitudinal damping has great influence on self-anchored suspension bridge’s fundamental frequency. With the increasement of damping, the fundamental frequence would increase.更多还原