斜交宽梁桥地震效应及减震策略研究

发布时间：2018-02-13 05:13

本文关键词： 斜交宽梁桥 LS-DYNA显式动力学台后填土速度脉冲地震动碰撞约束橡胶缓冲材料弹性拉索粘滞阻尼器　出处：《山东建筑大学》2015年硕士论文　论文类型：学位论文

【摘要】：斜交宽梁桥在公路和城市道路中广泛应用,与正交梁桥相比,斜交宽梁桥不对称的平面布置以及特殊的旋转趋势使其在地震中更容易遭到破坏,斜交宽梁桥的破坏的形式主要有：主梁与桥台背墙、挡块间的碰撞破坏,主梁在平面内的旋转导致位移过大甚至落梁,桥墩弯曲、扭转、剪切耦合破坏。现阶段对于斜交宽梁桥的减隔震方法的研究很少,本文以单跨斜交简支宽梁桥和三跨斜交连续宽梁桥为工程背景,采用LS-DYNA显式动力学分析方法,研究斜交宽梁桥在三向地震动作用下的动力效应和连续梁桥的减震措施,具体研究成果如下：1.在考虑台后填土约束的情况下,选择两条反应谱相同的速度脉冲地震动和人工拟合地震动,研究简支斜交宽梁桥的的平面旋转效应,结果发现：地震碰撞是桥台背墙和挡块对主梁的“碰撞约束”,是桥梁内部时有时无的动态约束。简支斜交宽梁桥主梁的旋转方向无统一的规律性：速度脉冲地震动不会加重主梁与桥台的碰撞。2.分析了连续斜交宽梁桥在两条频谱不同的地震动作用下的动力响应,从主梁平面旋转、支座屈服、墩底反力等方面分析桥梁的地震效应,然后在主梁与背墙之间以及主梁与挡块之间添加了橡胶缓冲材料,研究其减震减碰效果。结果发现：连续斜交宽梁桥的主梁旋转方向无单一的规律性,是不规则斜交梁桥在地震作用下的固有响应,梁端碰撞会改变旋转程度：中震作用下墩顶支座在水平约束方向易于屈服：橡胶缓材料对斜交宽梁桥梁端碰撞具有显著的减缓效果,且能有效减轻桥墩的弯扭耦合效应,但对支座没有起到很好的保护作用,对墩底的弯矩基本无减轻效果。3.研究了橡胶缓冲材料与弹性拉索组合,以及橡胶缓冲材料与线性粘滞阻尼器组合对连续斜交宽梁桥地震效应的减震效果。研究发现：在不同地震动作用下,橡胶缓冲材料与弹性拉索的组合能有效防止落梁,显著减小梁体旋转位移和墩底扭矩。橡胶缓冲材料与粘滞阻尼器组合能够非常有效地减小主梁的绝对位移和加速度,另外能有效的减小主梁与背墙和挡块的碰撞力；对墩底剪力和弯矩都有很好的减小效果,说明粘滞阻尼器的减震效果比较理想,并且支座屈服不会影响粘滞阻尼器的减震效果。
[Abstract]:Skew and wide beam bridges are widely used in highway and urban roads. Compared with orthogonal girder bridges, skew and wide beam bridges are more vulnerable to earthquake damage due to their asymmetrical plane arrangement and special rotation trend. The main failure forms of skew wide beam bridge include: main beam and abutment back wall, collision damage between the block, the rotation of the main beam in the plane leads to excessive displacement or even falling beam, pier bending, torsion, Shear coupling failure. At present, there is little research on the isolation method of skew wide beam bridge. In this paper, the single span skew beam bridge and three span skew continuous wide beam bridge are used as the engineering background, and the LS-DYNA explicit dynamic analysis method is adopted. This paper studies the dynamic effect of skew wide beam bridge under the action of three direction ground motion and the measures to reduce the vibration of continuous beam bridge. The concrete research results are as follows: 1. Under the condition of considering the constraint of the earth filling behind the platform, The plane rotation effect of simply supported skew wide beam bridge is studied by selecting two velocity pulse ground motions with the same response spectrum and artificially fitting ground motion. The results show that earthquake collision is a "collision constraint" between abutment wall and retaining block on the main beam, and is a dynamic constraint in the bridge from time to time. There is no uniform regularity of the rotation direction of the main beam of the simply supported skew beam bridge: velocity pulse earthquake. 2. The dynamic response of the continuous skew beam bridge under the action of two ground motions with different frequency spectrum is analyzed, which does not aggravate the collision between the main beam and the abutment. The seismic effect of the bridge is analyzed from the aspects of plane rotation of the main beam, bearing yield and reaction force at the bottom of the pier. Then the rubber buffer material is added between the main beam and the back wall and between the main beam and the block. The results show that the rotation direction of the main beam of the continuous skew beam bridge has no single regularity, which is the inherent response of the irregular skew beam bridge under earthquake. The beam-end impact will change the degree of rotation: under the action of moderate earthquake, the pier top bearing is prone to yield in the direction of horizontal constraint, and the rubber buffer material has a significant mitigation effect on the end-impact of skew wide beam bridge, and it can effectively reduce the coupling effect of bending and torsion of bridge piers. However, it has no protective effect on the bearing and has no effect on the bending moment at the bottom of the pier. 3. The combination of rubber buffer material and elastic cable is studied. And the effect of the combination of rubber buffer material and linear viscous damper on the seismic effect of continuous skew wide beam bridge is studied. It is found that the combination of rubber buffer material and elastic cable can effectively prevent the fall of beam under different ground motion. The combination of rubber buffer material and viscous damper can effectively reduce the absolute displacement and acceleration of the main beam, in addition, it can effectively reduce the collision force between the main beam and the back wall and block. The shear force and bending moment at the bottom of the pier are well reduced, which shows that the damping effect of the viscous damper is ideal, and the bearing yield will not affect the damping effect of the viscous damper.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U442.55

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