【作者】 黄超；

【导师】 肖光宏；

【作者基本信息】 重庆交通大学 ， 结构工程， 2011， 硕士

【摘要】 曲线梁桥是现代道路交通系统中最重要的桥型之一,随着我国基础设施建设大规模展开,越来越多的曲线梁桥被应用于城市高架桥和公路立交桥工程中。国内外学者对曲线梁桥的计算理论作了大量研究工作,计算机技术应用的普及,使得在结构计算中考虑材料非线性和几何非线性的影响成为可能。曲线梁预应力钢束为三维空间曲线,预应力的作用,使曲线梁处于空间受力状态,“弯-扭”耦合效应进一步加强。为了考察各预应力钢束作用下,曲线梁桥的支座反力分布规律与变形情况,为曲线梁桥预应力的设计和张拉施工提供技术参考,本论文以重庆融侨大道螺旋桥工程为依托,分析了预应力钢束的应力损失,并利用有限元软件ANSYS,对不同张拉方式进行数值模拟,比较内外侧支座反力与梁体位移的变化,另外,通过建立不同曲率半径的曲线箱梁桥模型,探究了半径对支反力分布和位移的影响。通过进行有限元模型计算,得出如下结论:①在自重作用下,连续曲线箱梁桥起终点处支座将产生横桥向支反力,内外侧支座的竖向反力不相等,起终点支座承受的竖向反力小于中间各墩。张拉预应力钢束将引起较大的横桥向、顺桥向支反力,内外侧支座竖向反力差值也将大幅度增加。②张拉单侧腹板中的预应力钢束将引起的支座反力分布严重不均,对称张拉、交错张拉预应力钢束引起的支反力分布较合理,有利于对预应力钢束张拉施工进行控制。内侧支座利用率不高,中间墩支座横向约束对桥梁的径向变形影响显著,边墩支座承受大部分横桥向反力。③连续曲线箱梁桥在自重和预应力作用下,将发生竖向、径向及顺桥向变形,竖向变形为主要变形,箱梁截面发生扭转和畸变,梁体向外侧翻。钢束张拉方式对变形影响较大,对称张拉和交错张拉时,径向变形较小,而当仅张拉单侧钢束时,梁体将发生较大的向内或向外径向位移。④横桥向、顺桥向支反力与桥梁曲率半径不成单调性变化规律,当曲率半径R = 150m时,横桥向支反力值达到峰值,内外侧支座竖向反力差随曲率半径增大而减小,当R > 150m时,差值曲线渐趋于水平,箱梁竖向位移随曲率半径增大而增大,当R > 200m时,这种影响变得不明显,箱梁横截面扭转和畸变变形随曲率半径增大而显著减弱。在进行曲线梁桥设计时,有条件的情况宜避免将半径设计在150 ~200m范围内。更多还原

【Abstract】 The curved beam bridge is one of the most important bridge forms in model road traffic system, with China’s large-scale infrastructure construction, more and more curved girder Bridges are applied to fly-over bridge in city and highway grade-separated interchange. Domestic and foreign scholars have researched a lot on computational theories about curved beam Bridges. And the popularization of computer technology’s application makes it possible to consider the influence of material nonlinearity and geometric nonlinearity in structural calculation. The prestressed steel is three-dimensional space curves, and the effect of prestressing force makes curved beam in a state of spatial stress which enhances the "bend - twist" coupling effect. In order to investigate the reaction regulation and deformation of curved beam under the effect of prestressing force, and provide technology references for curved beam prestress force’s design and construction, this paper rely on Chongqing Rong qiao avenue spiral bridge and has analyzed the loss of prestressing force. Meanwhile, the finite element software ANSYS has been applied to do numerical simulation for different tension ways. Inner and outer reaction and beam position changes also have been compared. After these, different curved girder bridges models in curvature radius were established to explore the influence radius gave to reaction and deformation changes. Through calculating finite element models, we get some conclusions below.①Under the dead weight, bearings will be counterproductive to the beginning and end of continuous curved girder bridge, the inner and outer vertical reaction is not equal, and which in the beginning and end is less than that in each pier in the middle. Prestressed steels will cause larger reaction in transverse and longitudinal, and longitudinal counterforce D-value inside and outside will increase greatly.②Prestressed steels in unilateral webs will cause serious uneven distribution of reaction, and whose distribution in symmetrical tension prestressed steels and staggered tension prestressed steels is reasonable, it’s conducive to control the construction of prestressed steels. The utilization rate of medial bearings is not high, and the middle piers’transverse constraint affects bridge’s deformation significantly. Side piers mostly bear transverse counterforce.③The continuous curved girder bridge will happen transverse, vertical and radial deformation under gravity and prestressing force. And vertical deformation as the main deformation, box girder section will happen torsion and distortion, beam body will turn outside. Steel beam tension will greatly affect deformation, and less vertical deformation in symmetrical tension and staggered tension. When steel beam tense from unilateral side, large inner or outer displacement will occur on beam body.④Transverse and vertical reactions don’t have monotonicity change rule with bridge curvature radius. When curvature radius R=150m, the transverse reaction reaches to peak. The inner and outer vertical reactions decrease with the increase of curvature radius; When R>200m, this influence is not obvious, box girder cross-sectional torsion and distortion deformation weaken obviously with the increase of curvature radius. Radius should be within 150-200m during designing curved girder bridges when the constructional condition is allowed.更多还原