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。
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.
引文
[1] Building Seismic Safety Council (BSSC).NEHRP Commentary on Guidelines for the Seismic Rehabilitation of Buildings[R]. FEMA368, developed for the Federal Emergency Management Agency.
[2] Seismic Evaluation and Retrofit of Concrete Buildings (Volume 1) ATC-40 [R]. CALIFORNIA SEISMIC SAFETY COMMISSION.
[3]杨成.结构弹塑性地震反应分析的改进能力—需求曲线方法研究(D).重庆:重庆人学,2003.
[4]北京金土木软件技术有限公司,中国建筑标准设计研究院.SAP2000中文版使用指南[M].北京:人民交通出版社,2006.
[5]彭俊生,罗永坤.结构概念分析与SAP2000应用[M].成都.西南交通大学出版社.2005.
[6]李胜林,邓映捷.通用结构分析与设计软件SAP2000中文版知识选讲(二),Pushover分析与SAP2000[J].建筑结构.技术通讯.2007.3.
[7]汪大绥,贺军利,张凤新.静力弹塑性分析(Pushover Analysis)的基本原理和计算实例[J].世界地震工程,2004,20(1).
[8] Building Seismic Safety Council (BSSC).NEHRP Improvement of Nonlinear Static Seismic Analysis Procedures FEMA440 [R].June 2005.
[9]叶列平.李琪.基于性能/位移的能力-需求曲线设计方法.现代地震工程进展—全国地震工程会议论文集[J].南京.东南大学出版社.2003.430-435.
[10] Yang Cheng, Zhao Renda. Improved Capacity Spectrum Method Using Structural Inelastic Re-sponse[J]. Journal of Southwest Jiaotong University. Vol.14.No.3. Jul 2006.
[11]中华人民共和国建设部.混凝土结构设计规范(GB50010-2002)[S].北京.中国建筑工业出版社.2002.
[12]叶列平.混凝土结构[M].北京:清华大学出版社,2005.8.
[13]过镇海,时旭东.钢筋混凝土原理和分析[M].北京:清华大学出版社,2003.
[14]江见鲸等.钢筋混凝土结构非线性有限元分析[M].北京,清华大学出版社.2005.
[15]王亚勇,刘小弟,程民贤.建筑结构时程分析法输入地震波的研究[J].建筑结构学报.1991.4.
[16]王亚勇等.建筑结构时程分析输入地震波的选择[J].建筑结构学报.1991.4.
[17]杨溥,李英民,赖明.结构时程分析输入地震波的选择控制指标[J].土木工程学报.2000.33(1).
[18]杨溥.基于位移的结构地震反应分析研究[J].重庆建筑大学博士学位论文.1999.
[19]包世华,张铜生.高层建筑结构设计和计算(下册) [M].北京.清华大学出版社.2007.
[20]尹之潜等.高层建筑的P—Δ效应和变形计算方法[J].地震工程与工程振动.1992.3.23-26.
[21] H.Krawinkler.Pros and cons of a pushover analysis of seismic performance evaluation[J]. En-gineering Structures.1998.20.
[22] R. S. Lawson, V. Vance and Helmut Krawinkler.Nonlinear static pushover analysis-why, when, and how? 5th U.S National Conference on Earthquake Engineering[J]. Chicago, Illinois. Jul. 1994. 283-292.
[23]中华人民共和国建设部.建筑抗震设计规范(GBJ50011-2001) [S].北京.中国建筑工业出版社.2001.
[24] WangYayong. Comparison of seismic actions and structural design requirements in Chinese Code GB50011 and International Standard ISO3010[J]. EARTHQUAKE ENGINEERING AND ENGINEERING VIBRATION.Vol.3, No.1. June 2004
[25]薛彦涛,徐培福,肖从真,徐自国.静力弹塑性分析(PUSHOVER)方法及其工程应用[J].建筑科学,2005,(6).
[26]叶献国.多层建筑结构抗震性能的近似评估——改进的能力谱方法[J].工程抗震,1998,(4):10-14.
[27]叶献国,种迅,李康宁,周锡元. Pushover方法与循环往复加载分析的研究[J].合肥工业大学学报(自然科学版),2001,24(6).
[28] A.K. Chopra, R. K. Goel. Capacity-demand-diagram methods for estimating seismic deforma-tion of inelastic structures: SDF systems. University of California[J], Berkeley. California US.PEER.Feb.1999.1-60.
[29]扶长生,应俊.静力非线性分析方法在抗震设计中的应用[J].结构工程师,2004,(3).
[30]汪梦甫,周锡元.高层建筑结构静力弹塑性分析方法的研究现状与改进策略[J].工程抗震,2003,(4).
[31]汪梦甫,周锡元.高层建筑结构抗震弹塑性分析方法及抗震性能评估的研究[J].土木工程学报,2003,(11).
[32] Min Liu, Y.K. Wen, Scott A. Burns.Life cycle cost oriented seismic design optimization of steel moment frame structures with risk-taking preference. Engineering Structures 26 (2004) 1407–1421.
[33]龚胡广,沈蒲生.一种基于位移的改进静力弹塑性分析方法[J].地震工程与工程振动,2005,(3).
[34]丁丽娜,林皋,李博宁.结构高度对静力弹塑性分析结果的影响[J].世界地震工程,2005,(1).
[35] Anil K. Chopra and Rakesh K. Goel .A modal pushover analysis procedure to estimate seismic demands for unsymmetric-plan buildings[J]. Earthquake Engng Struct. Dyn. 2004; 33:903–927.
[36]朱杰江,吕西林,杨震.高层建筑结构推覆分析的对比研究[J].建筑结构,2004,(10).
[37]庄云,郭子雄.竖向不规则结构的静力推覆分析[J].工程抗震与加固改造,2005,(11).
[38]叶燎原.结构静力弹塑性分析(Push-over)的原理和计算实例(J).建筑结构学报,2000.
[39]冯峻辉,闫贵平,钟铁毅.地震工程中的静力弹塑性(pushover)分析法[J].贵州工业大学学报(自然科学版),2003,(2).
[40] Li Yingmin, Yang Yaqiong, YangCheng. Analysis of Factors Influencing on Capacity-Demand Dia-gram Method and Preliminary Study on Improved Method Based on Demand Region [J], 8NCEE. 2006(9).
[41]杨仕升,秦荣,赵小莲,谢开仲.建筑结构抗震能力评估技术的研究及应用[J].世界地震工程,2004,(4).
[42]李灿灿,陆洲导,李凌志.建筑结构基于性能的抗震设计[J].四川建筑科学研究,2005,(5).
[43]李琪,顾荣蓉.基于位移的抗震设计中位移模式的确定[J].扬州大学学报(自然科学版),2005,(2).
[44]杨溥,李英民,熊振勇,夏洪流.能力曲线折线简化方法对比研究[J].重庆建筑大学学报,2005,(4).
[45]张晓,孙杰,.基于SAP2000多层钢结构静力弹塑性分析[J].山西建筑,2006,(22).
[46]黄群贤,林建华.建筑结构基于功能的抗震设计[J].工业建筑,2003,(4).
[47]邹昀,吕西林,.基于结构性能的抗震设计理论与方法[J].工业建筑,2006,(9).
[48]朱杰江,吕西林,杨震.高层建筑结构推覆分析的对比研究[J].建筑结构,2004,(10).
[49]吕西林,朱杰江.高层建筑结构推覆分析及对设计的启示[J].建筑结构学报,2005,(6).
[50]姜锐.建筑结构基于位移的抗震设计方法研究[J].太原科技大学学报,2005,(2).
[51]贾超,金峰,张楚汉,.基于功能的结构抗震设计研究进展[J].世界地震工程,2006,(1).
[52]于建,叶燎原,.结构抗震设计方法的发展[J].山西建筑,2006,(9).
[53]沙安,孙建华,白雪霜,毋剑平.《建筑抗震设计规范》GB50011-2001问答(9)[J].工程抗震,2004,(1).
[54]扶长生,应俊.静力非线性分析方法在抗震设计中的应用[J].结构工程师,2004,(3)