宽幅拱形独塔PC斜拉桥力学行为分析

发布时间：2018-08-02 09:46

【摘要】：为探究宽幅拱形独塔PC斜拉桥的力学行为特征,本文针对宽幅拱形独塔双索面PC斜拉桥的结构特点,基于梁格法进行了PC箱梁空间分析、无端锚索独塔体系的整体刚度及稳定性分析。针对背景工程主梁采用的逐段支架现浇施工法,分析了整体支架现浇、悬臂挂篮现浇施工及逐段支架现浇三者之间在施工过程及成桥状态的主梁线形及受力状态,对成桥状态还进行了结构动力分析。主要研究内容如下:(1)针对宽幅PC箱梁,研究不同截面划分方式对纵梁计算结果的影响,并以相同的简化结构,对比分析梁格法与实体单元法在应力、挠度、轴向压缩计算结果的区别,证明了应以各纵梁中性轴高度一致为原则根据箱梁腹板进行划分,且梁格法对于纵梁挠度计算的准确性高于应力计算;宽幅PC箱梁的横梁受到不可忽略的面外弯矩的影响,受力情况复杂,设计时因注重预应力在横向布置的均匀性,减小横梁受到的面外弯矩作用。(2)在不改变施工初张拉力的前提下,从拉索索力、主梁应力及施工预拱度设置方面进行了分析研究。证明了在不改变施工初张拉力的前提下,将逐段支架现浇施工变更为整体支架现浇施工具备可行性,在受力及变形方面受到影响较小,可以忽略;将逐段支架现浇施工变更为悬臂挂篮现浇施工具备可行性,但需要改变预拱度设置及成桥后调索方案。(3)研究活载作用下塔顶偏位及主梁最大挠度对塔柱刚度、拉索刚度、主梁刚度的敏感性,以及对不同位置拉索刚度的敏感性。证明了改变主梁截面腹板高度的优化设计方案为改善整体刚度的最佳方案。(4)结构动力分析。通过成桥后的结构动力特性分析,论证其抗风、抗震能力。(5)对研究内容进行了总结,并对后续研究进行了展望。
[Abstract]:In order to investigate the mechanical behavior characteristics of wide arch PC cable-stayed bridge with single tower, the space analysis of PC box girder is carried out based on the beam lattice method in view of the structural characteristics of PC cable-stayed bridge with wide arch single tower and double cable plane. Analysis of the overall stiffness and stability of the single tower system with no end Anchorage cable. In view of the construction method of stage by section support cast-in-place for the main beam of background engineering, the line shape and force state of the main beam in the construction process and the state of the bridge are analyzed, including the integral support cast-in-situ construction, the cantilever hanging basket cast-in-situ construction and the in-situ casting construction of the cantilever scaffold. The structural dynamic analysis of the bridge is also carried out. The main research contents are as follows: (1) for wide PC box girder, the influence of different cross sections on the calculation results of longitudinal beam is studied, and with the same simplified structure, the stress and deflection of beam lattice method and solid element method are compared and analyzed. The difference of axial compression calculation results proves that the box girder web should be divided according to the principle of uniform height of neutral axis of each longitudinal beam, and the accuracy of beam lattice method for calculating longitudinal beam deflection is higher than that of stress calculation. The cross beam of wide PC box girder is affected by the out-of-plane bending moment which can not be ignored, so the stress is complicated, so it is necessary to pay attention to the uniformity of the prestressing force in the transverse arrangement. (2) on the premise of not changing the initial tensile force, the cable force, the stress of the main beam and the setting of the pre-camber of the construction are analyzed and studied in terms of the cable force, the stress of the main beam and the pre-camber of the construction. It is proved that it is feasible to change the cast-in-place construction of step by step support to integral support without changing the initial tensile force of construction, and the influence on stress and deformation is small, which can be ignored. It is feasible to change the cast-in-place construction of step by section support into cantilever hanging basket cast-in-situ construction, but it is necessary to change the setting of pre-arch degree and the scheme of cable adjustment after completion of the bridge. (3) the study of tower top deflection and maximum deflection of main beam to column stiffness and cable stiffness under live load, The sensitivity of the stiffness of the main beam and the stiffness of the cable at different positions. It is proved that the optimum design scheme of changing the height of the web plate of the main beam section is the best scheme to improve the overall stiffness. (4) dynamic analysis of the structure. Through the analysis of the dynamic characteristics of the bridge, the wind-resistant and anti-seismic capacity of the bridge is demonstrated. (5) the contents of the study are summarized, and the future research is prospected.
【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】：U448.27

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