基于能量谱的概率地震需求分析及设计方法研究

发布时间：2018-07-05 04:26

本文选题：结构抗震性能评估 + 强度需求谱　；参考：《湖南大学》2014年博士论文

【摘要】：基于性能的抗震设计是21世纪抗震设计理论的一个主要研究方向。尽管这一理论从提出到目前为止已有几十年的时间，在理论研究以及实际应用都有了较大的发展。但目前来讲，该方法离实际应用和纳入规范还有较大的距离。基于性能的抗震设计其实主要分为对基于性能的抗震评估以及设计方法的研究。本文也是围绕这两方面开展了研究工作。 1.选用一定数量的远、近场记录对大量单自由度结构进行时程分析后，给出了等延性强度折减系数R的概率模型。该强度折减模型综合考虑了位移延性、场地土类别、远、近场地震等因素的影响；并引入了场地特征周期Tg对横坐标进行标准化处理，这样可以令由远、近场地震记录所得到结构强度需求统一在一个数学模型里。 2.选择多个强度指标与近场地震作用下结构能量需求之间进行了相关性分析，并得到了最优的强度指标IA（相关程度最高）。假定结构在往复地震作用下发生的滞回变形幅值相等，并对同一幅值作用下结构能经受的最大滞回环数neq进行了估计，建立了其与两参数（强度指标IA以及强度折减系数R）间的关系，并由统计分析后得到其回归模型。并以此为基础，进一步推导了滞回耗能模型以及总输入能模型。为了对比弹性输入能和非弹性输入能，本文引入了能量折减系数RE来考虑这一差异。 3.阐述Pushover方法的理论背景，认为对目标位移估计的精度是Pushover方法能否准确评估结构抗震性能的关键。文中从能量的角度来估计结构的目标位移；引入了层间剪力放大系数来体现结构地震水平力的分布；最后在自适应Pushover分析过程的基础上，提出了基于结构滞回耗能的Pushover分析方法。另外，结合了能力谱法对比分析了在两种位移需求谱下基于位移的抗震设计。最后，选用本文所提出的Pushover分析方法对所设计框架结构进行了抗震性能评估。 4.从能量平衡原则着手，本文建立了结构外部输入能与结构内部耗能之间的联系，并由此建立了基于能量的设计流程。该设计流程中还考虑了非弹性输入能、结构滞回模型以及远、近场地震记录等因素分别对设计结果的影响。最后，文中给出了单自由度结构（桥墩）以及多自由度结构的设计实例，验证了该设计方法的实用性。 5.推导结构的损伤指数模型，并且根据所提出的损伤模型对结构进行了损伤评估（易损性曲线）。在所构造的易损性曲线中，选用了与结构滞回耗能相关程度较高的IA强度指标作为横坐标。另外，，对相似框架结构的分析结果进行组合后，给出了组合的易损性曲线。最后，通过对一多层框架结构进行易损性分析，验证了本文方法的实用性。
[Abstract]:Performance-based seismic design is one of the main research directions of seismic design theory in the 21 st century. Although this theory has been put forward for several decades, it has made great progress in both theoretical research and practical application. But at present, the method is far from practical application and standard. In fact, performance-based seismic design is mainly divided into performance-based seismic evaluation and design methods. This paper also focuses on these two aspects of research work. 1. The probability model of equivalent ductility strength reduction coefficient R is given after a certain number of distant near field records are used to analyze a large number of single-degree-of-freedom structures. The strength reduction model takes into account the effects of displacement ductility, site soil type, distance, near-field earthquakes and so on. The structural strength requirements obtained from near field seismic records are unified in a single mathematical model. 2. The correlation analysis between several strength indexes and the energy demand of the structure under near-field earthquake is carried out, and the optimal strength index IA (correlation degree is the highest) is obtained. Assuming that the amplitude of hysteretic deformation of the structure under reciprocating earthquake is equal, the maximum number of hysteretic loops (neq) that the structure can withstand under the same amplitude is estimated. The relationship between the two parameters (the strength index IA and the strength reduction coefficient R) is established, and the regression model is obtained by statistical analysis. On this basis, the hysteretic energy dissipation model and the total input energy model are derived. In order to compare the elastic input energy with the inelastic input energy, the energy reduction coefficient RE is introduced to consider this difference. Based on the theoretical background of pushover method, it is considered that the accuracy of target displacement estimation is the key to evaluate the seismic performance of structures accurately by pushover method. In this paper, the target displacement of the structure is estimated from the point of view of energy; the interstory shear magnification factor is introduced to reflect the horizontal force distribution of the structure; finally, on the basis of adaptive pushover analysis, A pushover analysis method based on hysteretic energy dissipation is proposed. In addition, the displacement-based seismic design under two displacement-demand spectra is compared with the capacity spectrum method. Finally, the pushover analysis method proposed in this paper is used to evaluate the seismic performance of the frame structure. 4. Based on the principle of energy balance, the relationship between external input energy and internal energy consumption is established, and the design flow based on energy is established. The inelastic input energy, structural hysteretic model and far-field and near-field seismic records are also taken into account in the design process. Finally, the design examples of single degree of freedom structure (pier) and multi-degree of freedom structure are given, and the practicability of the design method is verified. The damage index model of the structure is derived, and the damage assessment (vulnerability curve) is carried out according to the proposed damage model. The IA strength index, which has a high correlation with the hysteretic energy dissipation of the structure, is selected as the transverse coordinate in the constructed vulnerability curve. In addition, after combining the results of the analysis of the similar frame structure, the vulnerability curve of the combination is given. Finally, the practicability of this method is verified by analyzing the vulnerability of a multi-layer frame structure.
【学位授予单位】：湖南大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU352.11

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