基于耗能杆连接的装配式混凝土框架抗震性能与功能可恢复研究

The seismic performance of precast concrete frame is one of the hotspots of current research. Based on the concept of seismic resilience, this project proposed a novel pre-stressed precast concrete frame with additional bamboo-shape energy-dissipation bars, to enhance the energy dissipation capacity of the frame. The energy-dissipation bars are employed in the beam-column connections, which exhibited significant plastic deformation along with the opening and closing of the interface between the beam and column, implementing damage concentration of the frame. Moreover, pre-stressed tendons provide the ability of self-centering, and the residual deformation of the frame can be effectively controlled, which is benefit of the repair after the earthquake. Seismic behavior the present project is to be studied from member level, connection level and structure level, and performance-based seismic design procedure is also to be proposed. Firstly, by conducting low-cycle fatigue experiments of energy-dissipation bars, the influence of key parameters on low cycle fatigue properties will be studied, and the relationship between the rotation of the end portion of the bar and the global stability will be established. Secondly, the influence of the areas and position of the energy-absorbing bars on the energy dissipation capacity of the connections will be explored through the beam-column connection test. The relationship among the stiffness of tendons, energy-dissipation bars and beam-column connections will be established to ensure self-centering of the connections. What’s more, by testing and FEM analysis of the frame, the distribution of the damage and failure modes will be observed, and the cumulative plastic deformation of the energy-dissipation bars and the residual deformation of the frame under near-field strong earthquakes will be investigated to evaluate the resilience of the frame. Finally, the seismic performance targets of pre-stressed precast concrete frame with additional energy-dissipation bars will be determined, and the performance-based seismic design procedure will be established.

装配式混凝土框架抗震性能是当前研究的热点之一。本项目基于可恢复功能结构理念，结合预应力装配式混凝土框架，提出新型竹形耗能杆来增强其节点和框架的耗能能力的方案。耗能杆设置于框架节点，梁柱连接界面缝隙的开合带动耗能杆产生塑性变形来消能，实现框架损伤的集中；震后，预应力筋提供节点自复位能力，有效控制框架残余变形，便于修复。本项目拟从构件、节点和结构三个层次研究抗震性能，并提出设计方法。首先，通过耗能杆的往复加载试验，研究耗能杆关键参数对低周疲劳性能的影响，并探究端部转动与耗能杆整体稳定的关系；其次，通过节点试验，研究耗能杆面积与布置方式对节点耗能能力的影响，并建立预应力筋、耗能杆和梁柱刚度之间关系，实现节点自复位；再次，通过框架试验和解析，观测结构损伤分布和失效模式，重点考察近场强震下耗能杆的累积塑性变形和框架的残余变形，并评估框架可恢复性能；最后，给出框架性能目标，建立其基于性能抗震设计方法。

开发具备稳定耗能性能的低廉耗能器，用以提高装配式混凝土结构的耗能能力，被认为是推动高烈度区装配式混凝土结构应用的关键技术之一。.项目基于新型耗能杆和装配式梁柱节点试验，针对耗能杆、附加耗能杆装配式自复位节点及附加耗能杆装配式自复位框架进行了系统研究。共发表高水平英文论文11篇，授权发明专利9项，培养研究生6人，参与获得国家科技进步二等奖等，主要工作如下：.(1) 提出了一种由竹节弹性段和竹间塑性段形成的新型竹形耗能杆，并通过试验评估了高耐久性铝合金竹形耗能杆和高性能全钢竹形耗能杆的滞回性能；对比了关键参数对耗能杆滞回性能、变形模式等的影响，结合屈曲理论给出了考虑竹节转动的内核波长修正公式；.(2) 提出了以高材料利用率为特征的部分约束型耗能杆，对比了不同加载制度、间隙以及屈服段长度对耗能杆滞回性能、变形模式、力学性能的影响，给出了部分约束耗能杆关于防扭转屈曲和防局部失效的设计方法。.(3) 开展了附加耗能杆预应力装配式混凝土节点试验，研究了不同加载制度、初始预应力、耗能杆参数以及安装形式对节点抗震性能的影响，揭示了预制梁柱主体结构在加载过程中基本保持弹性，同时给出了节点受压区高度计算值。.(4) 开展了叠合板-装配式后张混凝土节点试验研究，研究了不同试验参数下节点承载力、耗能以及自复位性能的变化规律，试验发现，节点在加载过程中基本未出现强度退化，在不经修复直接进行二次加载的条件下，其正负向强度均会出现明显的下降。.(5) 将附加耗能杆装配式混凝土节点分解为预制混凝土梁柱节点-预应力筋和预制混凝土梁柱节点-附加耗能杆两个子体系，并建立了节点宏观滞回模型，给出了节点滞回模型转动刚度以及特征点处弯矩、转角的计算公式；根据结构的能力曲线定义了结构的极限状态和破坏状态，并通过对数线性回归法求得结构概率需求模型参数。.上述研究不仅促进了消能装置的多样化和小型化，而且有助于推动高性能装配式混凝土结构研究和应用。