自复位桥墩的内禀侧移刚度和滞回机理研究

Research on the Intrinsic Lateral Stiffness and Hysteretic Mechanics of Self-Centering Pier

自复位桥墩由承重组件、自复位组件、耗能组件以及接头(如嵌合式接头)构成,具有良好的震后修复性和震后残余变形小的特点。对其承载力、侧移刚度以及滞回性能等力学特性进行理论分析,推导自复位桥墩的侧移刚度与承重组件墩身刚度、自复位组件刚度、耗能组件刚度、初始预拉力和桥墩几何尺寸的理论关系式;提出反映自复位桥墩内在固有属性的内禀侧移刚度概念及其计算式;自复位桥墩侧移刚度的上限为墩身刚度,下限为内禀侧移刚度。自复位桥墩的滞回曲线为扇片状,是耗能组件的耗能滞回性能与自复位组件的弹性复位性能叠加的结果。基于性能设计原则,并考虑合理控制震后残余变形,初步提出自复位桥墩的三步设计方法。

In general, Self-Centering Pier (SCP) consists of load bearing components, self-centering components, energy dissipaters and joints (e.g. tongue groove joint etc.). SCP has outstanding reparability and negligibly small post-earthquake residual deformation. Its mechanical characteristics, including bearing capacity, lateral stiffness and hysteretic behaviour are analyzed theoretically. The analytical expression of the lateral stiffness of SCP as a function of the flexural stiffness of load bearing components, the tensile stiffness of self-centering components and energy dissipater, the initial pretension and the physical dimension of pier is derived. The concept and formula of the intrinsic lateral stiffness of SCP are proposed to reveal the inherent property of SCP. The upper bound and lower bound of SCP lateral stiffness are the flexural stiffness of load bearing components and the intrinsic lateral stiffness of SCP respectively. The fan-bladed hysteretic behaviour of SCP is the result of superposing the hysteretic behaviour of energy dissipaters upon the self-centering components. Based on performance-based design principle, self-centering 3 steps (SC3S) design method in which post-earthquake residual deformation is considered, is proposed for engineering practice.