【作者】 杨亚琼；

【导师】 李英民；

【作者基本信息】 重庆大学 ， 防灾减灾工程及防护工程， 2008， 硕士

【摘要】 能力-需求曲线法是近年来在基于位移的抗震设计背景下被各国学者讨论得较多的研究方向。作为能力谱法的重要改进它能够解决使位移需求点所对应的结构非弹性特征和需求谱所对应的结构非弹性特征相一致的问题。需求区域的提出,构建了一种能力-需求曲线法的新思路,为了在工程应用中更好地利用这种思路,本文试图通过大型通用有限元软件SAP2000来实现需求区域,并力所能及地提出改进措施。当前能力-需求曲线法还存在如下问题:首先,现有能力-需求曲线法结构模型的建立误差以及对建立能力曲线和需求曲线模型的影响因素考虑不当所造成计算结果不准确。其次,如何考虑能力-需求曲线法和结构弹塑性动力反应分析之间固有的差异,并在此基础上对能力-需求曲线法的计算结果做修正以减小和动力反应分析结果之间的误差?为此,本文沿用需求区域的概念,有针对性地开展了一些工作:阐述了静力弹塑性分析方法的相关概念及发展历程;介绍了SAP2000静力弹塑性分析功能的基础——能力-需求曲线法的原理及分析步骤;列举了静力弹塑性分析和动力时程分析得出的结构反应的规律;针对已有的分析结论提出了对现有能力-需求曲线法的改进方案,通过算例分析验证了改进效果。本文得出的主要结论有:通过加速度加载和模态加载两种加载模式来近似模拟矩形加载和倒三角形加载模式,可以在SAP2000里得到两条推覆(能力)曲线;通过改变钢筋和混凝土的本构关系曲线,可以得到不同的需求曲线,取二者常用的本构关系的上下限,就可以得到需求曲线的包络;用SAP2000对不规则算例结构的正反两个方向进行推覆分析,所得结构反应差别不大;算例分析证明起包络作用的能力曲线和需求曲线所划分的变动区域可以更准确地确定pushover分析的结果;总结了结构弹塑性动力反应分析和静力弹塑性分析之间计算结果的相关性规律并加以了验证。更多还原

【Abstract】 In recent years, the method of capacity spectrum attracted much more attention in the field of structural engineering than ever before. The nonlinear characters of struc-tures may be developed to higher degree, when they are loaded the forces of earthquake. How can we make the intersection between the spectrums express the same nonlinear character with nonlinear spectrum? The intersection has the ability to express the top of structure’s displacement exactly? The concept of demand region constructs a new idea of capacity-demand curve method. In order to make better use of this idea, this the-sis is intended to use large universal finite element software SAP2000 to achieve de-mand region, and to propose improvement measures.First, the simplified capacity-curves have not enough precision and we can’t give right parameters for the program. For example, the intersection between the capacity curve and demand curve can’t represent the same kind of nonlinear state exactly. The excessively simplified capacity curves will reduce the precision of calculation using the method of capacity-demand curves. Some developed countries have their own elas-tic-plastic displacement spectrum, our country have not the spectrum yet. Then how can we calculate maximum top displacement of the refined member based nonlinear dy-namic time-history analysis of frame structures when the demand curves are to be cal-culated by the design response spectrum?The second, how to delete the discrepancy between the method of pushover analy-sis and the method of dynamic time-history analysis of structure? For example, the pushover curve analysis has no way to consider the hysteretic energy and the energy dissipation in other ways, and to consider the material fatigue and the scathe in the structures’to-and-fro motion.The work done in this thesis is mainly as follows for trying to make better of the capacity-demand curve in existence: 1. describe the related concepts and the develop-ment history of pushover analysis; introduce the principle and the analysis steps of ca-pacity-demand curve method, which is the basis of pushover analysis function in SAP2000. 2. Find the rules of structural response resulted from pushover analysis and dynamic elastoplastic analysis; the method of conversion relationship between the re-sults of the pushover analysis method and the results of structural dynamic time-history analysis is found. The main conclusions reached in this paper are: we can get two pushover (capacity) curves in SAP2000 through acceleration loading and mode loading instead of rectangu-lar loading and inverted triangle loading; we can get two demand curves through changing the constitutive relationship of steel bar and concrete, and through finding both the upper and lower limits of the constitutive relations, we can get the demand curve envelope; analyze the irregular structure examples by SAP2000 in both the posi-tive and negative direction ,the structural response is of little difference; the analysis of the selected examples confirms that envelope from the change of the demand region re-sulted from the change of demand and the capacity curves can more accurately deter-mine the results of the pushover analysis; summarize and verify the correlation law be-tween the pushover analysis and the dynamic time-history analysis preliminarily ; deal-ing with the results of the capacity-demand curve method according to this laws can re-duce the calculation error between the two methods.更多还原