薄壁空心桥墩的震损机理研究

发布时间：2018-03-09 08:19

本文选题：薄壁空心桥墩　切入点：高阶振型　出处：《中国地震局工程力学研究所》2015年硕士论文　论文类型：学位论文

【摘要】：本文对高墩大跨刚构桥梁的地震损伤机制进行研究,针对钢筋混凝土薄壁空心桥墩这种特殊构件的破坏机理进行了数值模拟与试验,重点考察了高阶振型对薄壁空心墩力学性能的影响。为了模拟整桥地震响应和损伤发展转移过程,发展了可协调多种物理域的子结构混合试验系统,利用界面单元方法,解决不同子域的边界协调问题。本文主要进行了如下的工作:第一,对薄壁空心桥墩进行了数值模拟,用相关试验结果标定数值模型。并进行了参数分析,研究轴压比与壁厚比对桥墩的影响,较大的壁厚比与较小的轴压比是有利的,高轴压比虽然可以抑制裂缝的发展,但是易出现脆性破坏。第二,对整桥进行了有限元建模,分析了桥梁的静力与动力响应,最后提取了子结构边界处的反力,为试验体加载方案的设计提供了依据。第三,制作了桥墩子结构试验体,在子结构边界处考虑三个自由度的协同加载,其中竖向两台作动器为力控制模式,模拟边界弯矩和轴力,水平方向位移控制;为了模拟分布质量,在1层隔板处设置另一个水平加载点,为力控制加载模式。弯矩、轴力、和水平荷载的比例关系是按照桥梁的第一振型比例计算出的。结果表明桥墩具有良好的延性。与不考虑边界弯矩的试验结果相比,归一化骨架曲线基本一致,说明加载方式对破坏模式的影响不大,但是本文的加载模式更加接近桥梁的真实受力状况。第四,针对子结构混合试验中不同物理域之间的边界协调问题,提出了界面单元的方法,利用约束变分原理进行了相关推导,并利用算例验证此种方法的精确性。第五,为在子结构混合试验中使用界面单元,引入静力凝聚与BFGS方法,这样只需要提取边界上的力与位移即可实现多子域不共节点的界面协调。
[Abstract]:In this paper, the seismic damage mechanism of long-span rigid frame bridges with high piers is studied, and the failure mechanism of the special members such as reinforced concrete thin-walled hollow piers is numerically simulated and tested. The influence of high-order modes on the mechanical properties of thin-walled hollow piers is emphatically investigated. In order to simulate the seismic response and damage development transfer process of the whole bridge, a hybrid test system for substructures, which can coordinate various physical domains, is developed, and the interface element method is used. The main work of this paper is as follows: first, numerical simulation of thin-walled hollow bridge pier is carried out, and the numerical model is calibrated with relevant experimental results. The influence of axial compression ratio to wall thickness ratio on bridge piers is studied. The larger wall thickness ratio and the smaller axial pressure ratio are advantageous. Although high axial compression ratio can restrain the development of cracks, it is prone to brittle failure. Secondly, the finite element method is used to model the whole bridge. The static and dynamic responses of the bridge are analyzed. At last, the reaction force at the boundary of the substructure is extracted, which provides the basis for the design of the loading scheme of the test body. Thirdly, the test body of the substructure of the pier is made. Three degrees of freedom co-loading are considered at the boundary of the substructure, in which two vertical actuators are force control mode to simulate boundary moment and axial force, horizontal displacement control, in order to simulate the distributed mass. Set another horizontal loading point at the 1st floor partition to control loading mode for force. Moment, axial force, The results show that the pier has good ductility. Compared with the experimental results without considering the boundary moment, the normalized skeleton curve is basically consistent. It is shown that the loading mode has little effect on the failure mode, but the loading mode in this paper is closer to the real stress condition of the bridge. 4th, aiming at the boundary coordination problem between different physical domains in the substructure mixed test, In this paper, a method of interface element is proposed, and the correlation derivation is carried out by using the constrained variational principle. The accuracy of this method is verified by an example. 5th. In order to use the interface element in the substructure mixing test, the static coacervation and BFGS method are introduced. In this way, only the forces and displacements on the boundary can be extracted to achieve the interface coordination of multi-subdomain non-common nodes.
【学位授予单位】：中国地震局工程力学研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U442.55

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