【作者】 张先蓉；

【导师】 杨德灿；

【作者基本信息】 武汉理工大学 ， 结构工程， 2004， 硕士

【摘要】 近几十年来，随着桥梁事业的飞速发展，斜拉桥的出现和设计施工技术的不断提高，斜拉桥跨径越来越大。斜拉桥的设计、结构分析以及施工难度也随之增加。虽然在确定斜拉桥的施工张拉力方面国内外已有不少研究成果，但在实际的应用中仍存在许多问题，缺乏完整求解的方法。 本文提出了以主梁线形为控制目标的斜拉桥施工中张拉索力的确定方法。该方法的思路是：将已知的成桥状态作为倒拆计算的开始，对斜拉桥进行倒拆分析，从而得到一个倒拆计算中的施工张拉索力。再以此索力作为正装计算的控制张拉索力，通过正装计算得到一个成桥状态。调整成桥状态的索力，反复进行倒拆、正装计算，使得成桥后主梁线形达到设计线形。最后采用最小二乘法对正装和倒拆两个步骤中得到的索力进行修正，得到施工中的斜拉索的张拉索力。 本文利用通用有限元软件，采用空间拉索单元，空间梁单元和刚臂单元以及特殊的支承单元，建立了斜拉桥全桥的三维有限元模型。计算过程中计及了拉索的垂度效应，弯矩和轴力对主梁和主塔的组合效应以及结构的大变形效应等几何非线性影响因素，采用Newton-Raphson方法和位移收敛准则进行迭代求解。 通过理论分析和实例计算，本文得到以下结论：1)把空间有限元单元用于斜拉桥的施工中张拉索力的确定中去，可得到与实际值相吻合的结果。2)施工阶段的正装和倒拆分析中考虑斜拉桥的几何非线性因素影响，而且必须经过正装与倒拆的反复迭代才能得到理想的成桥状态，才能将正装倒拆计算中结构的不闭合问题减小到最低限度。更多还原

【Abstract】 In recent decades, with the high-speed development of bridges, the appearance of cable-stayed bridges and the improvement of construction technique, the span of the cable-stayed bridge becomes longer and longer. The difficulty of the cable-stayed bridge design, structure analysis and construction becomes higher and higher accordingly. Though in the aspects of the tensile inclined cable forces solution during the construction states have been studied a lot in foreign country and home, there are also many actual problems and lack of an integrated method to solve.This paper presents a method that the reasonable inclined cable forces during the construction process are determined by the target configuration of girder. The thought of this method is that beginning with the existing finished bridge state, the backward analysis is used to get the tensile cable forces of the construction process. Then the forward calculation is also used to get the tensile cable forces of the construction process to gain a finished bridge state under the control of the former forces. After modulating these two finished bridge state, another new backward analysis and forward analysis are carriedon again and again. The target configuration of girder attains to the designed configuration at last. Using the least squares method to modulate the inclined cable forces both in forward analysis stage and backward analysis stage, the tensile inclined cable forces during construction will be get finally.The usual finite software is used in this paper. The three-dimension cable element, three-dimension girder element, rigid element and special support element are used to build the finite element model of the whole cablestayed bridge. These geometric nonlinear behaviors such as the sag of inclined cables caused by their own dead weight, the interaction of large bending moment and axial forces in girders and towers, and the large displacement effects are considered during calculation. Newton-Raphson method and the displacementconvergence norm are used to approach the solution iteratively.The conclusions are got from the theory analysis and project example calculation in this paper as following: that the three-dimension finite clement model used in calculating the cable forces during the construction will get good results corresponding to the actual solution smoothly. The influence caused by geometric nonlinear behaviors should be considered in forward analysis and backward analysis during construction processes. Only the reasonable finished bridge state should be got by approach iteratively of forward analysis and backward analysis, the non-circled problems of the results between forward analysis and backward analysis will reach to the minimum degree.更多还原