【作者】 高鸽子；

【导师】 赵人达；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2012， 硕士

【摘要】 斜拉桥由于其桥型美观、跨越能力强以及施工方便在近年来得到了快速发展。作为一种高次超静定柔性受力体系,与连续梁和桁架梁相比较,斜拉桥特别是大跨度斜拉桥,几何非线性影响较为突出,而且影响因素也较多。主要表现在：首先,随着斜拉索长度的增加,垂度效应渐渐明显,即索的伸长量与索拉力不成正比关系,这主要是由斜拉索自重引起的。其次,由于结构本身为柔性体系,承受外荷载时整个结构的变形较大,大位移问题突出。这种影响改变了荷载对结构上其它节点产生的弯矩。如果位移量过大,则会严重影响荷载对结构的效应。最后,由于轴力与弯矩的相互作用,斜拉桥特别是大跨度斜拉桥几何非线性的分析非常复杂。可以说,几何非线性对斜拉桥受力性能带来的影响已成为目前斜拉桥发展的重要制约因素。目前认为,影响斜拉桥几何非线性的因素主要包括三个方面：垂度效应、大变形效应、弯矩—轴力组合效应。本文首先介绍了斜拉桥的起源及发展历史,然后对斜拉桥的几何非线性研究方法进行了全面评述。最后以重庆丰都长江二桥设计方案为依托进行了实例分析。具体的研究内容和取得的成果如下：(1)介绍斜拉桥几何非线性分析理论及其在实际计算中的应用,分析斜拉桥各种非线性因素产生的原因及其影响。(2)针对丰都长江二桥设计方案建立有限元模型,模拟丰都长江二桥的施工过程,对其进行施工过程和成桥后的几何非线性分析。(3)几何非线性对主梁弯矩的影响以斜拉索垂度的影响最大,大位移影响次之,弯矩与轴力组合效应影响最小,而且不同的施工阶段影响程度也不同。(4)考虑温度荷载时,车辆荷载作用下,斜拉桥几何非线性较为明显,不可忽略。更多还原

【Abstract】 Recently, Cable-stayed bridge has been rapidly developed because of beautiful appearance, long-span capacity and convenient construction. As a kind of flexible structure with high static indetermination, compared with continuous beam and truss beam bridges, the effect of geometrical nonlinearity of cable-stayed bridge is more outstanding and the influence factors are also more, especially for long-span cable-stayed bridge. These factors mainly manifested in the following aspects:Firstly, with the increase of the length of the cable, the sag generated by self-weight of the structure increase also, at the same time, the elongation and the tension of the cable is not in proportional relation. Secondly, the geometric deformation of the whole structure is larger, performed as a notable large displacement, that is when the load in cable-stayed bridge structure effect just for a node, the node will occur displacement, the load will also move. This displacement will change the bending moment on the other node produced by the load. If the displacement amount is large, it will seriously affect the effects of the load on the structure. Coupled with the axial force and bending moment interaction effects, it will make the geometrical nonlinear of long span cable-stayed bridge analysis more and more complex. Geometric nonlinearity of cable-stayed bridge has become the important restriction factor to the development of cable-stayed bridge.The effect of geometrical nonlinearity of cable-stayed bridge includes three aspects:, cable-sage effects,combined effects of bending moment and axial force and large displacement.First, this dissertation introduces the history and development of cable-stayed bridge, and then describes the research status of the theory of geometric nonlinearity for cable-stayed bridge. Lastly, taking the2th changjiang river bridge of chongqing fengdu as research background the author did some instance. The main contents and conclusions of the research are listed as follows:Firstly, there is a introduction of the geometrical nonlinear analysis of cable-stayed bridge and its application in actual calculation, then, the author analysis the reasons and effects which caused by various nonlinear factors.(1) Based on the design scheme of the2th fengdu changjiang river, we established a finite element model to simulate the actual construction process, and then analysis the geometric nonlinearity of construction stage and completed stage.(2) Geometrical nonlinearity which affect the bending moment of the main girder, cable-sag has the most obvious effect and nonlinear of large displacement has greater effect, while the combined effect of moment and axial force has the least influence. Further, the effect degree is different in different construction phase.(3) Taking account of the temperature load, geometric nonlinear of vehicle load is obvious, so it can not be ignored.更多还原