空心薄壁矩形桥墩的抗震性能分析

发布时间：2018-05-28 20:42

本文选题：空心薄壁墩 + ABAQUS　；参考：《南华大学》2015年硕士论文

【摘要】：在地震作用下,常常发生桥墩破坏使整座桥梁发生倒塌的工程事故。桥墩地震响应的研究,对整个桥梁工程抗震研究起关键作用。西部地区地势险要、深山沟壑,需要修建较高的桥墩才能跨越山区。桥墩越高,需要的截面尺寸越大,为了节约成本、减轻自重、增强柔性,一般情况下采取空心截面形式。在大震作用下,大部分桥墩进入弹塑性变形阶段,采用完全弹性理论进行结构分析和设计已经难以满足实际需要,因此,对桥墩结构进行弹塑性地震分析就显得越来越重要。本文采用大型有限元软件ABAQUS,对空心薄壁桥墩的地震反应进行研究,为完善我国桥梁抗震设计规范具有非常重要的意义。本文通过理论分析与数值模拟相结合的方法,对典型空心薄壁桥墩的抗震性能进行研究,主要研究内容为:(1)本文对6个大比例空心薄壁桥墩在低周反复水平荷载作用下进行仿真分析,探讨桥墩在复合受力下的滞回特性、骨架曲线、位移延性和耗能能力,并分析纵向配筋率、配箍率、轴压比对桥墩承载能力和延性性能的影响。结果表明:1)位移延性系数介于1.99-4.42之间;影响空心薄壁桥墩抗震性能的主要因素是体积配箍率,随其值的增加,承载力略微提高,但延性显著增大;2)随着轴压比的提高,其承载力提高,延性下降,对高配筋率影响较大;3)配筋率能够提高结构的承载能力,但变形能力降低;在较大轴向压力作用下,配筋率对空心薄壁桥墩的影响较为明显;4)空心薄壁墩抗震性能符合一般钢筋混凝土构件,但能节省材料,降低成本。(2)建立4个大比例有限元模型,研究在相同配箍率(不计重叠部分箍筋体积)情况下,不同箍筋配置形式下的延性和强度,得出结论:在钢筋混凝土中配置一定数量的箍筋,有利于提高混凝土的强度和延性,增加耗能能力;当配置复合(重叠)箍时,产生较大的塑形变形,延性最好,混凝土极限应变达到0.00871,相比不配置箍筋情况下提高5.29倍,相比配置直拉结箍筋情况下提高了0.482倍;增加对角拉结箍筋时,延性略微提高,但不便于施工;空心薄壁墩的四个内外角受力较大,在施工条件允许情况下,角部应做成一定形式的倒角。(3)运用静力弹塑性分析(Push-over)方法的原理和实现方法,建立能力谱和地震需求谱曲线,评估空心薄壁矩形桥墩在不同地震作用下的反应。
[Abstract]:Under the action of earthquake, the failure of pier often results in the collapse of the whole bridge. The research on the seismic response of pier plays a key role in the seismic research of the whole bridge project. The western region has a dangerous terrain and deep mountains and gullies, so it is necessary to build high piers to cross the mountains. The higher the pier is, the larger the section size is. In order to save cost, reduce weight and enhance flexibility, hollow section is adopted in general. Under the action of large earthquakes, most piers have entered the stage of elastoplastic deformation, and it is difficult to use the theory of complete elasticity to analyze and design the structure. Therefore, it is more and more important to carry out the elastoplastic seismic analysis of the pier structure. In this paper, the seismic response of hollow thin-walled piers is studied by using the finite element software Abaqus, which is of great significance to improve the seismic design code of bridges in China. In this paper, the seismic behavior of typical hollow thin-walled bridge piers is studied by combining theoretical analysis with numerical simulation. The main research content is: (1) in this paper, six large proportion hollow thin-walled bridge piers are simulated and analyzed under low cyclic and horizontal loads, and the hysteretic characteristics, skeleton curves, displacement ductility and energy dissipation capacity of the pier under composite loading are discussed. The effects of longitudinal reinforcement ratio, hoop ratio and axial compression ratio on the bearing capacity and ductility of piers are analyzed. The results show that the displacement ductility coefficient is between 1.99-4.42. The main factor affecting the seismic performance of hollow thin-walled bridge piers is the volumetric hoop ratio. With the increase of the ratio, the bearing capacity increases slightly, but the ductility increases significantly with the increase of axial compression ratio. The bearing capacity is increased, the ductility is decreased, and the reinforcement ratio can increase the bearing capacity of the structure, but the deformation ability is decreased, and under the action of large axial pressure, the reinforcement ratio can increase the bearing capacity of the structure. The effect of reinforcement ratio on hollow thin-walled bridge piers is obvious. 4) the seismic behavior of hollow thin-walled piers conforms to the general reinforced concrete members, but it can save materials and reduce the cost. 4 large scale finite element models are established. The ductility and strength of different stirrups are studied under the same ratio of stirrups (excluding the volume of overlapping stirrups). It is concluded that a certain number of stirrups in reinforced concrete can improve the strength and ductility of concrete. The maximum strain of concrete is 0.00871, which is 5.29 times higher than that without stirrups, and 0.482 times higher than that in the case of Czochralski stirrups. The ductility of hollow thin-walled piers is increased slightly, but it is not convenient for construction. The four inner and outer angles of hollow thin-walled piers are subjected to greater forces, and if the construction conditions permit, the ductility of the hollow thin-walled piers is very large. The angle should be made into a certain form of chamfer. 3) the principle and realization method of static elastic-plastic analysis (Push-over) method is used to establish the capacity spectrum and seismic demand spectrum curve to evaluate the response of hollow thin-walled rectangular pier under different earthquakes.
【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U442.55;U443.22

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