节点文献
新型铅阻尼器与预应力装配式框架节点抗震性能研究
Study on New Lead Dampers and Seismic Behavior of Prestress Assembling Beam-Column Connections
【作者】 刘猛;
【作者基本信息】 北京工业大学 , 防灾减灾工程及防护工程, 2008, 博士
【摘要】 预应力装配式混凝土框架结构集预应力混凝土结构与装配式混凝土结构的优点于一体,具有生产效率高、产品质量好、对环境影响小、有利于可持续发展等优点,是一种符合建筑结构未来发展方向的结构体系。本文在分析国内外相关方面研究的基础上,针对此结构体系耗能较低、地震反应较大的弱点,研发了一种新型耗能减震装置,进行了此耗能装置与安装此耗能装置的无粘结预应力装配混凝土框架节点抗震性能的理论分析和试验研究,主要内容概括如下:(1)发明了新型铅阻尼器。在充分分析已有阻尼器相关技术性能及适用范围的基础上,发明了耗能效率高、性能稳定、耐久性好、占用空间小、有放大位移及转角功能的新型转动式铅剪切阻尼器。(2)新型转动式铅阻尼器的理论分析及试验研究。采用有限元理论和周期性动力试验的方法,分析和研究了诸如铅块长宽高、荷载幅值、加载频率等对此阻尼器耗能性能的影响及其整体工作性能。研究结果表明,在一定的铅块长度和宽度范围内,阻尼器的阻尼力基本上随铅块长度和宽度的增大而线性增加,而铅块高度对阻尼力的影响则相对较小,但随铅块高度的增大,阻尼器的初始刚度有所降低;加载位移幅值较小时,阻尼器就进入塑性阶段工作,开始耗散能量;中低加载频率对阻尼器虚拟的影响较小,可以忽略。总之,该阻尼器滞回环较为丰满,基本呈矩形或平行四边形,工作性能稳定,可以实现在结构小位移情况下产生较大耗能能力的目标,且加工工艺简单、耐久性好、体积较小。(3)安装阻尼器与未安装阻尼器预应力装配混凝土框架节点的数值模拟和试验对比研究。采用数值模拟和低周反复荷载试验方法,研究和分析不同预应力度、预应力筋位置、梁端配筋形式、阻尼器阻尼力等条件下预应力装配混凝土框架节点的破坏机理和抗震性能。分析和试验结果表明,安装阻尼器后,节点的耗能能力得到很大提高,承载能力也得到了一定程度的增强,且未对节点的延性产生明显影响;构件的破坏模式依然保持梁铰破坏模式,混凝土的损伤和破坏仍然发生在梁端局部,是结构在强地震作用下,受力最佳、损失最小且有利于震后修复的一种破坏模式。总之,新型转动式铅阻尼器能够非常有效地提高预应力装配混凝土框架结构抗震能力,具有良好的工程应用价值。(4)杆式铅剪切阻尼器及其耗能减震分析。针对现有耗能装置一般都占用一定使用空间、影响空间布局的弊端,提出一种不占用使用空间、在结构内部安放并与结构形成一体且无需检修的耗能装置。有限元数值模拟结果表明,该耗能装置能够明显地提高钢筋混凝土框架节点和框架结构的耗能能力,具有潜在的工程应用前景。
【Abstract】 Prestress assembling concrete structure have higher performances than other concrete structure forms, possessing the advantages of pretressed concrete and assemble concrete being characteristic of safe, economy, high production rate, assurance of quality, reducing environmental disturbance and contributing to sustainable development, according with the development direction in the future, etc. Based on the studies at home and abroad, experimental and theoretical studies on the seismic performances of pretress assembling concrete beam-column connections added passive energy dissipation device are carried out here in order to improve the ability of energy dissipation and reduce seismic responses. The main research contents as follows:(1) An invention of new lead damper. On the basis of intensive analysis of technical performance and application scope of existing dampers, a new lead damper of displacement-amplifying type is developed with characteristics of high efficiency of energy dissipation, stable performance, good durability, little space occupation, etc.(2) Theoretical and experimental studies on the damper which is developed in this paper are carried out. Finite element method and periodic dynamic testing method are used to analyze the influencing factors for the damper, such as length, width, height of lead block and amplitude, frequency of load, etc. The results show that the rolling type lead shear damper realizes the preconcerted aim of better energy dissipation capability on the condition of small displacement. The hysteretic curve was chubby and the approximate parallelogram distribution characteristics. The restoring force model of the damper is been suggested on characteristics of restoring force. The damper is characterized by simple process, lower cost, small area. The lead shear damper is suitable for vibration control of building structures.(3) Theoretical and experimental studies on the behavior of prestress assembling concrete beam-column connections added passive energy dissipation devices and without them are carried out. By finite element method and experimental research, the performance and parameters of beam-column connections added energy dissipation device is investigated. The parameters include magnitude of prestress, location of prestressing tendon, form of reinforcement in the end region of beam and different yield forces of damper. Stress distribution, failure mode, hysteresis characteristics, deforming capacity, cracks development, energy dissipation and stiffness degradation are studied. The research results show that the energy dissipation capacity of joint added energy dissipation device is improved greatly and that is proved that the damper proposed in this paper maintains a good energy dissipation property, stable performance, and makes up for the weaknesses of low energy dissipation ability of prestress assembling concrete structure, provide essential technical conditions for its application in earthquake area. The structure added damper increase its carrying capacity, influence the ductility less. The failure mode of prestress assembling concrete structure added this damper is still“beam end plastic hinge failure mechanism”. This failure mode is beneficial to stress distribution with minimum damage, and structural repair.(4) A new energy dissipating device is proposed in this paper, which is characterized by doing no take up service space, forming one body with structure so that the problem of existing energy dissipating device occupying large service space is solved. By finite element method frame joints and frame structure added this energy dissipating device is investigated in several case. The results show that vibration energy dissipation ability of is notable, do not take up extra space, and do not need the maintenance in the future.
【Key words】 concrete structue; prestress assembling; beam-column connection; structure control; lead damper;