地震作用下高架桥梁碰撞过程中的波动行为及减震控制

Focused on the inconsistent between the structural acceleration obtained by existing pounding model in analysis and the local acceleration affected by pounding stress wave during test, this project presents the studies on the measurement method of pounding stress wave field and acceleration field. The identification method of accurate pounding force which is based on pounding stress wave and acceleration response of highway bridges is developed. Through finite element analysis (FEA) of structural pounding, the relationship between the local wave propagation and structural vibration of superstructure is investigated. Then, the mechanism of stress wave generation and propagation during pounding and the characteristic of stress wave is revealed. Additionally, the mechanism of difference between the existing pounding model and the real stress state of the bridge is analyzed.A distributed mass pounding model considering the stress wave field effect is proposed and investigated. The parameters of above pounding model reflecting stress wave interaction are also derived and determined. Subsequently, the mechanical behaviors and self-recovery ability of a kind of novel composite materials made of metallic pseudo-rubber and shape memory polymer under impact loading is analyzed. Based on this material, the pounding control method, corresponding mitigation effect and self-recovery properties of highway bridges are also investigated. Through this project, the pounding wave propagation behaviors and the relationship between the structural vibration and local stress wave in highway bridges during earthquake will be revealed in detail. Additionally, bridge pounding theories and analysis methods considering stress wave propagation effect will be further developed and novel self-recovery bridge pounding system will be also presented. It will also make a contribution to the development of bridge engineering. So this project is of great impprtance in the scientific significance and practical value in the safety of urban transport network and post-disaster rescue under earthquakes.

本项目针对现有碰撞分析模型中整体加速度与试验测试的应力波产生的局部加速度之间的巨大差异，研究地震作用下高架桥梁碰撞应力波场和加速度场测试方法，以及基于应力波和加速度试验测试数据的碰撞力识别方法；通过结构碰撞有限元分析，研究桥梁碰撞过程中上部结构波动与整体振动的关系，揭示碰撞过程中应力波生成、传播机制及应力场特征、现有宏观碰撞模型与桥梁实际受力状态差异的机理；研究基于碰撞应力波场的高架桥梁碰撞分布质量分析模型、碰撞模型及其参数计算方法；研究金属橡胶-形状记忆聚合物复合材料在冲击荷载下的力学行为与自恢复特性，以及基于该材料的高架桥梁碰撞控制分析方法、效果与自恢复特性。本项目研究将深刻揭示地震作用下高架桥梁碰撞波动行为及波动与振动的相互关系，发展基于应力波的桥梁碰撞分析理论与方法、以及自恢复桥梁碰撞控制体系，丰富桥梁地震工程科学，对城市交通网络地震安全与灾后应急救援具有重要的科学意义和实用价值。

针对高架桥梁在地震中的碰撞应力波对桥梁结构及测试系统的影响，本项目研究了高架桥梁碰撞过程中的应力波和加速度场的空间分布特征，提出了桥梁地震碰撞自恢复减震设备及方法：（1）测试得到了碰撞过程中的应力波信号和加速度信号，明确了应力波的波速、种类及空间分布特征；（2）建立了高架桥梁碰撞分布质量体系分析模型，得到了一维桥面板在碰撞过程中局部质点振动的解析解，数值得到了加速度在不同位置处的峰值分布规律；（3）结合高精度有限元模型得到了整体振动与刚体振动的关系，提出了局部质点加速度和与刚体振动加速度的换算公式，解释了实际试验中局部振动加速度用于后续计算分析存在局限性的问题，给出了单元网格划分精度要求；（4）基于自恢复形状记忆合金橡胶材料，试验和理论研究了该新型碰撞缓冲器的力学性能及其桥梁碰撞过程中的减震效果和可恢复性，研究结果表明，本项目提出的新型自恢复减震控制装置可以有效降低地震灾害，提高高架桥梁体系在地震中的自恢复能力。