低屈服点钢防屈曲支撑及其框架抗震性能研究

发布时间：2018-05-15 00:25

本文选题：低屈服点钢 + 防屈曲支撑　；参考：《清华大学》2015年博士论文

【摘要】：防屈曲支撑可以解决普通支撑在地震往复作用下的受压屈曲问题,具有稳定的承载力。低屈服点钢初始屈服强度低,强屈比高,延性好,将其作为内核材料的防屈曲支撑,在地震中较早屈服,通过塑性变形耗能减震,像“保险丝”一样保护主体结构的安全。带有低屈服点钢防屈曲支撑的钢框架是一种高效的抗震结构体系。本文通过试验研究、理论分析和数值模拟,从低屈服点钢的材料性能出发,对低屈服点钢防屈曲支撑及其框架的抗震性能进行了系统的研究和评价,并给出了设计建议。本文的主要研究内容包括以下6个方面:(1)通过试验测定了20个低屈服点钢材试件的单调和循环加载性能,标定了混合强化参数并进行验证,为低屈服点钢的计算分析提供了基础数据(第2章)。(2)完成了低屈服点钢材为内核材料的防屈曲支撑的滞回性能试验,采用第2章的数据,在通用有限元软件ABAQUS中对试验进行了数值模拟。通过86个防屈曲支撑数值算例的计算结果,给出了支撑关键几何参数的设计建议(第3章)。(3)结合第3章的试验和数值模拟结果,通过分析支撑的宏观荷载-位移曲线的特点,提出防屈曲支撑的等效模型,比较了支撑采用精细化有限元模型的多尺度框架-支撑结构和支撑采用等效模型的简化框架-支撑结构在静力和动力时程下的结果,并通过振动台试验验证了简化模型的准确性(第4章)。(4)完成了低屈服点钢防屈曲支撑框架、2类普通支撑框架、2类普通强度防屈曲支撑框架各9组结构和6个纯框架的共计408组罕遇地震时程分析,从构件状态、层剪力、层间位移等方面比较了不同结构的性能;通过低屈服点钢防屈曲支撑框架的增量动力分析,研究了其两道抗震防线的工作机理(第5章)。(5)完成了51个低屈服点钢防屈曲支撑框架和3个纯框架共计3024组动力时程分析,基于层间位移角和构件损伤指标定义了不同的性能水平,对低屈服点钢防屈曲支撑框架结构进行了抗震性能评价和易损性分析,比较了支撑刚度和形式以及层数的影响,给出了各结构层间位移角或构件损伤指标随地震动强度的变化曲线,以预测结构在给定地震动强度下的性能水平(第6章部分)。(6)考虑低屈服点钢材的刚度退化特点,提出了低屈服点钢防屈曲支撑在结构中的设计方法;给出了低屈服点钢防屈曲支撑超强系数的建议值;按不同结构类型,给出了不同性能目标所需支撑的最小刚度列表,为该结构的性能化设计提供了实用建议(第6章部分)。
[Abstract]:Anti-buckling bracing can solve the buckling problem of common braces under earthquake reciprocating, and has stable bearing capacity. The low yield point steel has low initial yield strength, high ratio of strength to yield and good ductility. It is regarded as the anti-buckling support of the core material, yielding early in earthquake, dissipating energy through plastic deformation, and protecting the safety of the main structure as "fuse". Steel frame with low yield point steel buckling braces is an efficient seismic structure system. Based on the experimental research, theoretical analysis and numerical simulation, the anti-buckling braces of low-yield point steel and the seismic behavior of the frame are systematically studied and evaluated based on the material properties of the low yield point steel, and the design suggestions are given. The main contents of this paper include the following six aspects: 1) the monotonic and cyclic loading properties of 20 low yield point steel specimens were measured by experiments, and the mixed strengthening parameters were calibrated and verified. The hysteretic properties of buckling brace of low yield point steel as core material were tested by the basic data (Chapter 2, Chapter 2) for calculation and analysis of low yield point steel, and the data of Chapter 2 were used. Numerical simulation of the test is carried out in the general finite element software ABAQUS. Based on the calculation results of 86 numerical examples of buckle-resistant braces, the design suggestions for key geometric parameters of braces (Chapter 3) are given. The characteristics of macroscopic load-displacement curves of braces are analyzed by combining the experimental results and numerical simulation results in Chapter 3. An equivalent model of buckle-resistant braces is proposed. The results of multi-scale frame-braced structures with fine finite element model and simplified frame-braced structures with equivalent braces are compared under static and dynamic time history. The accuracy of the simplified model is verified by shaking table test (Chapter 4, No.4). The low yield point steel buckling bracing frame is completed. Two kinds of ordinary bracing frames, two types of ordinary strength bracing frames, 9 groups of structures and six pure frames are completed. A total of 408 sets of rare earthquake time history analysis, The performance of different structures is compared from the aspects of member state, story shear force and interstory displacement, and the incremental dynamic analysis of steel buckling braced frame with low yield point is carried out. In this paper, the working mechanism of its two seismic lines (Chapter 5) has been studied. The dynamic time history analysis of 51 low yield point steel buckling braced frames and 3 pure frames has been carried out in 3024 groups. Based on the interstory displacement angle and damage index of members, different performance levels are defined. The seismic performance evaluation and vulnerability analysis of low yield point steel buckling braced frame structures are carried out, and the effects of bracing stiffness and form, as well as the number of stories, are compared. In order to predict the performance level of the structure under given ground motion intensity, the variation curves of the displacement angle between layers or the damage index of each structure are given in order to predict the stiffness degradation characteristics of steel with low yield point considering the performance level of the structure under the given ground motion intensity (Chapter 6). The design method of low yield point steel buckling bracing in structure, the suggested value of super strength coefficient of low yield point steel buckling bracing, and the minimum stiffness list of bracing required for different performance objectives are given according to different structure types. Practical suggestions are provided for the performance design of the structure (Chapter 6).
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU391;TU352.11

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