连续梁桥多阶段适时控制连接体系减震机理及关键技术研究

The fixed-pier of continuous beam bridges almost bear all the longitudinal seismic load of superstructure under strong earthquakes, which can cause the damage of the fixed-pier and the expansion joint , and even result into falling beam. In order to solve the shortcoming of the continuous beam bridges, one idea using anti-seismic potential of sliding piers to bear the longitudinal seismic force together with fixed-pier was came up. But if the connection between the beams and sliding piers was a rigid connection, the natural vibration period of continuous beam bridges would be shortened, then increase the whole seismic response of continuous beam bridges. For this reason, the concept of “multi-stage timely control connection(MTC)” was proposed and the MTC connection devices is developed. The device is designed to be installed between sliding piers and beams, when the device plays the role, the connection stiffness between the beams and sliding piers is changing according the working environment, which can prohibit the relative displacement in a multi-stage timely control connection manner between sliding piers and beams once the earthquake occurs and help the fixed-pier to collaboratively bear the longitudinal seismic force, thus reduce the seismic response of fixed-pier and improve the seismic performance of continuous beam bridge. The constitutive relation of the MTC was studied base on the force, time and displacement with the multi-stage connection status, then the mechanical model of the MTC was researched. The seismic response, damping mechanism, the capacity protected measure of sliding piers, effect parameters of MTC devices and other key technologies of MTC system for continuous beam bridges were studied. On the base, the method of seismic control was conducted for analysis of continuous beam bridge by considering displacement response, internal forces response, and pounding response. The research can provide the theoretical support and technical reference for the seismic design of new continuous beam bridge and the seismic strengthening of existing continuous beam bridge, which not only has theoretical significance, but also has practical application value.

为解决地震作用下连续梁桥上部结构纵向地震荷载只由固定墩承担，易引发固定墩和伸缩缝破坏，甚至造成落梁的问题，提出利用滑动墩抗震潜能，协同固定墩共同承受纵向地震作用的思想。为避免梁体和滑动墩刚性连接导致桥梁自振周期缩短，继而引发整体地震响应增大问题，提出了“多阶段适时控制连接（MTC）”的概念，针对连续梁桥地震损伤特征，通过MTC装置将梁体和滑动墩分阶段按需连接，建立多墩协同抗震的连续梁桥MTC减震体系，提高连续梁桥抗震性能。基于多阶段连接状态的力、时间和位移关系，推导MTC装置力学本构，建立MTC单元力学模型，针对不同场地类型、不同结构参数的连续梁桥，研究MTC体系的地震响应特征、减震机理、滑动墩能力保护及MTC装置参数影响等减震关键技术，基于连续梁桥位移响应、内力响应和梁间碰撞目标要求，提出连续梁桥MTC体系减震控制策略，为新建连续梁桥抗震设计及既有连续梁桥抗震加固提供理论支撑和技术参考。

为解决地震作用下连续梁桥上部结构纵向地震荷载只由固定墩承担，易引发固定墩和伸缩缝破坏，甚至造成落梁的问题，提出利用活动墩抗震潜能，协同固定墩共同承受纵向地震作用的思想。为避免连接刚度固定导致不同地震动作用下梁体和活动墩连接刚度过大或过小，继而引发中小地震作用下整体地震响应大幅增加或大震作用下减震效果不佳问题，采用理论分析、数值模拟和试验相结合方法，研发了多阶段适时控制连接减震（MTC）装置，基于力、位移和时间关系构建了MTC装置力学本构，建立了考虑“动态刚度”的MTC装置力学模型，提出了一种连续梁桥MTC减震体系，研究其减震机理和减震效果，研究结果表明MTC分区设置可实现分级控制，有效提高连续梁桥抗震性能。基于分区介入连接刚度的目的，开展了MTC装置刚度分区取值分析，明晰了连续梁桥MTC装置刚度分区取值原则；开展了MTC装置结构参数、环境参数和对象参数对连续梁桥MTC减震体系的影响规律研究，得到了参数影响的一般规律；进行了MTC装置优化改进，针对MTC装置的连接刚度、滞回性能、骨架曲线等性能指标开展参数影响显著性分析，揭示了MTC装置抗震性能的显著影响因素；开展了连续梁桥MTC减震体系布设方法及优化策略分析，研究了梁间碰撞效应对连续梁桥MTC减震效果影响，在此基础上提出了连续梁桥MTC装置减震应用策略。