自复位双柱式摇摆桥梁抗震设计方法及工程应用

Seismic Design Method and Its Engineering Application of Self-centering Double-column Rocking Bridge

为发展具有损伤可控特性和自复位能力的摇摆结构新型桥梁抗震体系,对自复位双柱式摇摆桥梁的抗震设计方法及其工程应用进行研究。在摇摆桥墩受力机理和旗帜形滞回分析模型基础上,提出其在消压、屈服和设计极限状态的计算方法,并给出限定残余位移侧移率小于1%的回复能力验算公式。考虑到摇摆桥墩的力学行为和变形特点,提出直接基于位移的摇摆桥梁结构抗震设计方法,给出设计原则及具体的设计步骤,并把该方法成功应用到黄徐路跨线桥梁抗震设计中。在此基础上,数值分析不同设计地震作用下摇摆桥梁结构的性能状态及其性能指标,并介绍了中国首座自复位摇摆桥梁工程——黄徐路摇摆桥梁工程实践,展示了实桥应用中的一些抗震构造细节。研究结果表明:提出的验算公式可为设计计算提供充分的理论依据;E1地震作用下耗能钢筋没有屈服且具有较高的安全储备;在E2地震作用下,随着桥梁发挥摇摆功能,摇摆桥墩刚度减小,地震力增幅变小,有效实现了结构减震功能,且震后桥墩残余位移较小,可忽略不计,实现了结构自复位功能,满足了既定的抗震设计目标。

To develop a new type of bridge seismic system of the rocking structure with the damage control characteristics and self-centering capability, the seismic design method and engineering application of the self-centering double-column rocking bridge were investigated and further discussed. Based on the force mechanism of rocking piers and the analysis model of flagshaped hysteresis, the calculation methods of the residual displacement of the rocking pier in the depressing state, the yield state and the design limit state were proposed. And the verification formula of recovery ability was given, when the drift ratio of residual displacement was limited to less than 1%. Considering the mechanical behavior and deformation mode of the rocking piers, adirect displacement-based seismic design method for rocking bridge was put forward and the design principles and design steps were proposed. Then the design method was successfully applied to the seismic design of the Huangxu road overpass. The performance state and its index under different levels of earthquake excitation for rocking bridge were analyzed by the numerical simulation. Furthermore, the first self-centering rocking bridge project--Huangxu Road Overpass project was established, and some seismic structural details of the bridge were demonstrated. The results show that the proposed formula provides the sufficient theoretical basis for the design and calculation. The energy dissipation steel bars does not yield and has a high safety redundancy under E1 earthquake. Under E2 earthquake, with rocking piers, the stiffness of the rocking piers decreases. The increase of seismic force becomes smaller and smaller, and the structural damping function is realized effectively. The residual displacement of the pier is small and can be neglected. The self-centering function and the goals of the established seismic design are achieved.