自复位防屈曲支撑结构抗震性能及设计方法

发布时间：2018-11-21 10:03

【摘要】：现代城市应具备在大灾难后足够的恢复能力，使得人的生活不因灾难而受到大的影响。自复位体系正是在这样的背景下产生的。现有的自复位体系大多采用形状记忆合金或者复合有机材料充当复位筋，两者造价均较高。另外，部分自复位体系/支撑采用摩擦耗能机制，摩擦面的老化及稳定性是一个棘手的问题。防屈曲支撑以其饱满稳定的滞回性能获得很多研究者及工程师的青睐，，但是，其弹塑性耗能机制使得结构震后产生不可忽略的残余变形。针对以上问题，本文进行了以下工作。（1）综合考虑防屈曲支撑及自复位体系的优点，提出了一种新型防屈曲支撑——自复位防屈曲支撑（SCBRB）。在此基础上，给出复位材料的选择方案和设计方法。如果综合复位及耗能能力，则预应力与耗能内芯屈服强度相等时为最佳方案。通过对纯防屈曲支撑、纯复位支撑及自复位防屈曲支撑拟静力试验对比表明：复位防屈曲支撑基本消除了纯防屈曲支撑的残余变形，具有良好的复位效果和相当的耗能能力。（2）给出单自由度防屈曲支撑体系的几个重要参数，并给出了单自由度防屈曲支撑结构的恢复力模型与这些参数之间的关系。通过对自复位钢框架结构的时程分析，对比了自复位防屈曲支撑、防屈曲支撑及普通钢框架的抗震性能；通过参数分析，给出结构设计时几个重要参数的建议取值。通过对不同梁端连接方式的结构抗震性能的研究发现，梁对柱子转动约束能力越弱，则柱子弹性变形能力越强，结构也就越柔。当地震强度很大时，则梁端铰接体系更有利于消除残余变形。（3）对等效线性化方法在自复位防屈曲支撑结构的应用进行了研究。通过20条地震记录下两种等效线性化方法求得位移，并与非线性时程分析结果进行对比，结果表明等效线性化方法对于自复位结构的精度比理想弹塑性结构更高；等概率幅值平均等效线性化方法由于考虑了所有位移对等效阻尼和等效刚度的贡献，因此更为精确。（4）基于非线性位移比，提出一种直接计算自复位结构位移的方法。首先，通过对453600个单自由度体系进行非线性时程分析，得到各类场地统计意义上的等强度位移比谱。然后对位移比谱进行参数分析，得到各个参数对位移比的影响规律。最后，对位移比进行多元非线性回归，得到了位移比的公式。（5）针对目前大部分结构抗震设计方法均需要迭代以及现有的基于位移直接设计方法的不足这一现状，提出一种基于位移的自复位防屈曲支撑结构直接设计方法。首先，通过大量的统计回归，得到了结构强度折减系数关于位移比的公式。然后，根据目标位移和公式便可计算出结构与支撑的所有主要参数。经其设计的结构是偏于安全的，有效地消除了残余变形。
[Abstract]:Modern cities should be able to recover enough after a catastrophe so that people's lives are not greatly affected by disasters. It is in this context that the self-reset system is produced. Most of the existing self-reset systems use shape memory alloys or composite organic materials as reposition tendons, both of which are expensive. In addition, friction energy dissipation mechanism is used in partial self-reset system / brace, and the aging and stability of friction surface is a thorny problem. Buckling braces are favored by many researchers and engineers for their full and stable hysteretic properties. However, the elastic-plastic energy dissipation mechanism results in the residual deformation of the structure after earthquake. In view of the above problems, this paper has carried out the following work. The main results are as follows: (1) considering the advantages of anti-buckling brace and self-reduction system, a new type of anti-buckling brace (SCBRB).) is proposed. On this basis, the selection scheme and design method of the reset material are given. If the comprehensive reset and energy dissipation capacity are combined, the optimum scheme is when the yield strength of the prestressing and energy dissipation cores is equal. The comparison of pseudo-static test of pure buckling bracing, pure reset bracing and self-reset anti-buckling bracing shows that the reduced anti-buckling bracing basically eliminates the residual deformation of pure anti-buckling bracing, and has good reset effect and equivalent energy dissipation ability. (2) several important parameters of single-degree-of-freedom buckle-resistant bracing system are given, and the relationship between the restoring force model of single-degree-of-freedom buckling bracing structure and these parameters is given. Based on the time-history analysis of self-reset steel frame structure, the aseismic performance of self-reset buckling bracing, buckling bracing and ordinary steel frame is compared, and the suggested values of several important parameters in structural design are given through parameter analysis. By studying the seismic behavior of structures with different beam end connections, it is found that the weaker the beam is to the column, the stronger the elastic deformation ability of the column is and the more flexible the structure is. When the earthquake intensity is high, the beam end hinge system is more favorable to eliminate the residual deformation. (3) the application of equivalent linearization method to self-reset buckling braced structures is studied. The displacement is obtained by two equivalent linearization methods under 20 seismic records and compared with the results of nonlinear time-history analysis. The results show that the accuracy of the equivalent linearization method for self-reset structures is higher than that for ideal elastic-plastic structures. The equal-probability average equivalent linearization method is more accurate because it takes into account the contribution of all displacements to the equivalent damping and stiffness. (4) based on the nonlinear displacement ratio, a direct method for calculating the displacement of self-reset structures is proposed. Firstly, through the nonlinear time history analysis of 453600 single-degree-of-freedom systems, the iso-intensity displacement ratio spectra in the statistical sense of all kinds of sites are obtained. Then the parameter analysis of the displacement ratio spectrum is carried out and the influence of each parameter on the displacement ratio is obtained. Finally, the multivariate nonlinear regression of displacement ratio is carried out, and the formula of displacement ratio is obtained. (5) in view of the fact that most seismic design methods need iteration and the shortcomings of the existing direct displacement-based design methods, a displacement-based direct design method for buckling braced structures is proposed. Firstly, the formula of structural strength reduction coefficient about displacement ratio is obtained by a large number of statistical regression. Then, all the main parameters of the structure and bracing can be calculated according to the target displacement sum formula. The designed structure is relatively safe and effectively eliminates the residual deformation.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU352.11

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