曲线箱梁桥整体稳定性设计研究

发布时间：2019-01-24 14:51

【摘要】：由于曲线梁桥能够很好的适应地形环境、实现各向交通的互通互达,同时线条流畅、明快,具有律动感,因此在城市立体交通和高等级公路中得到了广泛的应用,且以箱梁桥为主。由于曲线梁桥的受力和变形特点与直线梁桥相差较大,但设计和施工中对此认识不到位,以致全国各地曲线梁桥出现了一些病害,归结起来有:梁体整体的平面位移;梁体外侧翻转倾覆;下部墩柱失稳造成的上部梁体坍塌,这些事故给社会造成了不良的影响和经济损失。这些现象均属于曲线梁桥的整体稳定性问题,因此设计中如何提高曲线梁桥的整体稳定性,避免桥梁结构稳定性的先天不足,则显得至关重要。论文从曲线梁桥的稳定性几何设计、抗倾覆设计、支承体系设计等方面进行了探讨,尤其是对支承体系设计问题,论文运用MIDAS计算软件进行数值建模分析,从梁体平面约束支承、梁体抗扭支承、墩梁固结设计三个方面分三个专章进行了研究,即论文的第四、五、六章内容。曲线梁桥径向位移的产生一部是由于纯平面力(整体温度、混凝土收缩、离心力、制动力)的作用;另一部分则是由于梁体扭矩变形而引起的径向位移。梁体受到的横向约束刚度越大,梁体在平面作用力下产生的径向位移值越小,但同时约束支座的径向支反力也越大,因此设计中应根据具体的情况综合考虑,一般而言墩梁固结的横向刚度大于固定支座的横向刚度。曲线梁桥切向位移约束不宜太强,否则梁体在整体温度、混凝土收缩等作用下,将产生平面反拱,增大径向位移。设置抗扭支座的位置将产生很大的扭矩内力,从而调整梁体的扭矩分布,墩梁固结较抗扭双支座调整扭矩的作用明显。对于独柱墩采用预设支点偏心方式可调整扭矩分布,附加反向扭矩与偏心值成线性关系,在中、边墩同时进行偏心,将加强扭矩调整的程度,基本上是仅偏心中墩时调整扭矩值的2倍。当曲率较大时,预设支承偏心不能完全消除内侧支座受拉的状态,此时则应调整抗扭支座间距,避免脱空。采用墩梁固结方式可以调节梁体扭矩分布,避免出现支座脱空。但是墩梁固结使曲线梁桥形成了一个小刚构结构体系,墩和梁协同受力和变形。随着墩高的降低,线刚度的增加,除制动力和离心力外,墩顶其余荷载效应也在增加,特别是墩顶纵桥向弯矩My值影响较大,轴向力N影响可忽略不计。当墩高不变,随着固结墩个数的增加,墩顶轴力和横桥向弯矩变化不大,纵桥向弯矩的增加较多,除制动力荷载外,其他荷载产生的My值随着固结个数的增加而增加。因此在墩梁固结设计时,应综合曲线桥梁上下部结构受力综合考虑,权衡利弊。当墩高矮小于5-10m,线刚度较大时,固结的墩应越少,同时避免对联长较长的边墩进行对称性固结。
[Abstract]:Because the curved girder bridge can adapt to the terrain environment very well, realize the intercommunication and mutual access of the various directions traffic, at the same time the lines are smooth, bright and quick, have the rhythm sense, so it has been widely used in the city three-dimensional traffic and the high-grade highway. And the main box girder bridge. Because the stress and deformation characteristics of curved girder bridge are quite different from that of straight beam bridge, but in the design and construction of the curved girder bridge, there are some diseases in the design and construction, which can be summed up as follows: the plane displacement of the whole beam body; The overturning and overturning of the outside of the beam and the collapse of the upper beam caused by the instability of the lower pier have caused adverse effects and economic losses to the society. These phenomena all belong to the whole stability problem of curved girder bridge, so how to improve the overall stability of curved girder bridge and avoid the inherent shortage of bridge structure stability is very important in the design. In this paper, the stability geometric design, anti-overturning design and support system design of curved girder bridge are discussed. Especially, the design of supporting system is discussed, and the numerical modeling analysis is carried out by using MIDAS software. There are three chapters in this paper, namely, the fourth, fifth and sixth chapters, from three aspects: plane constrained support, torsional support and consolidation design of pier beam. The radial displacement of curved girder bridge is partly caused by the pure plane force (integral temperature, concrete shrinkage, centrifugal force, braking force) and partly by the radial displacement caused by the torsional deformation of the beam body. The larger the transverse restraint stiffness of the beam is, the smaller the radial displacement of the beam is under the plane force, but at the same time, the larger the radial support reaction force of the restrained support is, so the design should be considered comprehensively according to the concrete situation. Generally speaking, the transverse stiffness of pier beam consolidation is greater than that of fixed support. The tangential displacement constraint of curved girder bridge should not be too strong, otherwise the beam body will produce plane reverse arch and increase radial displacement under the action of integral temperature and concrete shrinkage. Setting the position of torsional bearing will produce great internal force of torque, thus adjust the distribution of torque of beam body, and the effect of adjusting torque of pier beam consolidation is more obvious than that of anti-torsion double support. The torque distribution can be adjusted by preset pivot eccentricity for the single column pier, and the additional reverse torque is linearly related to the eccentricity value. In the middle and side pier, the degree of torque adjustment will be strengthened if the eccentric is carried out at the same time. Basically is only the eccentric middle pier when adjusts the torque value 2 times. When the curvature is large, the eccentricity of the preset bearing can not completely eliminate the tension state of the inner bearing, and the distance between the torsion bearing should be adjusted to avoid the void. The torque distribution of the beam can be adjusted by means of the consolidation of piers and beams, and the pedestal detachment can be avoided. However, the consolidation of pier and beam makes the curved beam bridge form a small rigid frame structure system. With the decrease of pier height and the increase of linear stiffness, the load effect on the pier top is also increasing except for the braking force and centrifugal force, especially the My value of the longitudinal bridge bending moment at the top of the pier is greatly affected, but the influence of the axial force N is negligible. When the pier height is constant, with the increase of the number of consolidation piers, the axial force at the top of the pier and the bending moment of the transverse bridge do not change much, but the bending moment of the longitudinal bridge increases more. The My value generated by other loads increases with the increase of the number of consolidation loads except for the braking force. Therefore, in the design of pier and beam consolidation, comprehensive consideration should be given to the stress of the upper and lower parts of the curved bridge, weighing the advantages and disadvantages. When the height of the pier is less than 5-10m and the linear stiffness is larger, the less the piers should be consolidated, and the more symmetrical consolidation of the long side piers is avoided at the same time.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U442.5;U448.213

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