摘要
钢筋混凝土烟囱是工业生产中重要的工程项目,属于典型高耸结构体系,对水平侧移产生的P-△效应反应比较敏感。由于现代工业发展的需要,烟囱高度也向越来越高的方向发展,更加大了P-△效应的影响。虽然国内学者研究结构的二阶效应已取得了很大的成就,但是现阶段钢筋混凝土烟囱结构的软件设计过程中,对于烟囱二阶效应的分析还有待澄清,需做进一步的研究。
本文分析总结了钢筋混凝土结构二阶效应的分析方法,着重对高耸结构P-△效应的分析方法进行了研究。在考虑钢筋混凝土烟囱受P-△效应的影响时,采用能量法推导出适用于烟囱设计的计算公式,对烟囱结构的内力与变形进行具体的计算。运用卡氏第一定理与最小势能原理,得出烟囱在风荷载作用下的结构顶点位移、底部附加弯矩和弯矩放大系数。同时按照烟囱设计规范计算风荷载作用下底部附加弯矩和顶点位移,比较两种方法计算结果之间的差别。通过比较,得出考虑烟囱结构刚度折减系数的合理值。比较折减之后的能量法与烟囱设计规范两种计算结果之间的差别。
研究静力弹塑性分析方法,采用Sap2000对烟囱进行静力弹塑性分析,得出结构荷载-位移曲线与结构的整体变形曲线。将该分析曲线与能量法所选用的形函数曲线进行比对,看是否一致。
对240m烟囱进行Sap2000有限元分析,得出在不同刚度折减系数下,结构的顶点位移和内力分布情况。通过比较不同刚度折减系数下的顶点位移值与应力分布情况,选择与烟囱设计规范和能量法结果相一致的刚度折减系数。
The reinforced concrete chimney is an important project in industrial buildings, which is a typical high-rise structure, and it is sensitive to P-Δeffect caused by horizontal displacement. With the development of modern industry, the chimney is more and more high which make us pay more attention on the P-Δeffect of chimney. In despite of the research about second-order effect of structure has made great achievements, but the analysis about second-order effect of chimney remains to be clarified in the process of chimney design, and need to do further research.
This paper which analyze and summary the measures of second-order effect of reinforced concrete structure, and focus more attention on the analysis of P-Δeffect of high-rise structure. Considering the impact of P-Δeffect, derive the reasonable chimney design formula on the basis of energy method, and go into the specific calculation of inter forces and deformation. By using the Castigliano's first theorem and minimum potential energy principle, the apical displacement and additional bending moment at the bottom and moment magnification coefficient of chimney can be obtained when the chimney under the action of wind load. Figure out the bottom additional bending moment under wind load based on criterion of chimney design, and compare the difference of results which derive from the two approaches. By comparison, the reasonable value of chimney stiffness reduction coefficient can be achieved. Compare the two results derived from criterion of chimney design and energy method when consider stiffness reduction into account.
Based on nonlinear static analysis method, carrying on chimney pushover analysis by SAP2000, and obtain the load-displacement curve and the Integral deformation curve of chimney. Compare curves derived from analysis with curve of shape function of energy method, and by compare to see if they consistent or not.
Doing the finite element analysis of chimney with the height of 240m by SAP2000, the apical displacement and situation of internal force distribution under different stiffness reduction coefficient can be gained. By compare the apical displacement value and stress distribution under different stiffness reduction coefficient, selecting a reasonable stiffness reduction coefficient and making the achieved result consistent to result derived from standard of chimney design and energy method.
引文
[1]周冬,魏兵,郑福玲,范丽肖.脱硫电厂烟囱选型分析[J].河北电力技术,2006,25(2):24-26.
[2]王肇民.高耸结构的发展与展望[J].特种结构,2000,(1):47.
[3]郑欢.烟囱在水平地震力和温度作用下的结构性能分析[D].西安:西安建筑科技大学,2008.
[4]汤卓,王雪,束磊磊,吕令毅.210 m高异形烟囱横风向动力响应研究[J].建筑结构,2110,40(2):100-102.
[5]蒋洪平,张相庭.变截面高耸结构的横向风振研究[J].振动与冲击,1994,(1):46-54.
[6]刘季,何立民.高耸结构与高层建筑的竖向地震作用[J].建筑结构学报,1988(2):1-12.
[7]程岩.竖向地震作用对高柔结构的影响[J].西北地震学报,1999,21(4):423-427.
[8]杨春田,于淑琴.烟囱在竖向地震作用下计算方法探讨[J],特种结构,1989,(2):4-10.
[9]李庆祥,孙炳楠,楼文娟等.高耸异型烟囱结构风压和风振系数试验研究[J].试验力学,2005,20(4):615-622.
[10]刘亚琦,梁枢果.高烟囱的横风向共振研究[J].特种结构,2004,21(3):57-59.
[11]刘亚琦, 梁枢果.圆截面高耸结构的横风向风振研究[D].武汉:武汉大学硕士论文,2004.
[12]牛春良.烟囱横向风振计算[J].特种结构,2004,21(3):6062.
[13]张伟,梁兴文.超高层框筒伸臂结构受力和变形性能探讨[J].建筑结构学报,2008(赠刊):170-175
[14]刘建新.高层建筑结构P-△效应实用计算方法[J].建筑结构,1995,(2)15-18
[15]陈加猛.高层框筒、筒中筒结构的二阶效应分析[D].广州:华南理工大学博士论文,1997.
[16]李战平.钢筋混凝土多、高层结构二阶效应实用设计方法探讨[D].重庆大学硕士论文,2006.
[17]程光均,于海洋,白绍良,武建华.钢筋混凝土框架柱挠曲侧移二阶效应的整体考虑[J].建筑结构,2006.36(7):44-46.
[18]童申家,童岳生.风荷载及竖向荷载作用下框架的侧移二阶效应[J].建筑结构,2006.36(7):41-43
[19]胡其高,何煌,谢建军,朱卫华.二阶效应的荷载判别公式[J].工业建筑,2007.37:652-655.
[20]T.Paulay, M. J.N.Priestley, John Wiley and Sons. Seismic Design of Reinforced concrete and Masonry Buildings[M].New York, Inc.605 Third Avenue,1992.
[21]L.K., Stevens. Elastic Stability of Practical Multistory Frame[J].Proceedings of the Institution of Civil Engineers,1967
[22]朱占友.钢筋混凝土结构二届效应若干问题研究[D].重庆:重庆大学硕士论文,2006.
[23]Gupta and Krawinkler. Estimation of seismic drift demands for frame structures. Earthquake Engineering and Structural Dynamics,2000,29(9):1287-1305
[24]E.L. Wilson and A.Habibullah, Static and dynamic analysis of multi-story buildings including P-delta effects. Earthquake Spectra,1987,3(2):134-141.
[25]王文达,韩林海.钢管混凝土框架力学性能的简化二阶弹塑性分析[J].清华大学学报,2009,49(9):23-26.
[26]赵永峰,童根树.等强度折减下延性结构的位移放大系数[J].哈尔滨工业大学,2009,41(8):107-110.
[27]王柯,李天,张猛.用于钢框架结构二阶分析的一种实用塑性区数值模型[J].世界地震工程,2008,24(3):49-53.
[28]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,2005.2(6):100-107.
[29]刘毅,钢筋混凝土结构二阶效应及设计方法的研究[D].重庆:重庆大学博士论文,2007.
[30]E.Rosenblueth. Slenderness Effect in Buildings. Journal of the Structural Division [J],ASCE, 1965.
[31]童根树,赵永峰.动力P-△效应对地震力调整系数的影响[J].浙江大学学报,2007,(1):120-125.
[32]陈麟,张耀春,周云.二阶效应对巨型钢框架结构时程分析的影响[J].四川建筑科学研究,2004,30(4):12-14.
[33]周奎,郑七振,翟立祥.空间钢框架结构的二阶渐进弹塑性分析[J].上海理工大学学报,2004.26(1):53-58.
[34]周绪红,莫涛.交错桁架结构体系的空间二阶弹塑性全过程分析[J].土木工程学报,2005,38(8):10-14.
[35]朱达力,王珊珊,朱镜清.高耸结构P-△效应分析的精度问题[J].哈尔滨建筑大学学报,2002,35(3):49-51.
[36]兰鹏,陆念力.复合载荷下高耸结构P-△效应的精确解析[J].哈尔滨工业大学学报,2003,35(7):790-791.
[37]王光远.结构动力学[M].北京:高等出版社,2006.
[38]王秀逸,张平生.特种结构[M].武汉:地震出版社,1997.
[39]刘志鸿.特种结构[M].西安:冶金工业出版社,1984.
[40]中华人民共和国国家标准,烟囱设计规范(GB 500512002)[S].北京:中国建筑工业出版社,2002.
[41]中华人民共和国国家标准,高耸结构设计规范(GB 501352006)[S].北京:中国建筑工业出版社,2006.
[42]中华人民共和国国家标准,建筑结构荷载规范(GB 500092001)[S].北京:中国建筑工业出版社,2001.
[43]汪大绥,贺军利,张凤新.静力弹塑性分析的基本原理和计算实例[J].世界地震工程,2004,20(1):45-53.
[44]陆新征,叶列平,缪志伟.建筑抗震弹塑性分析[M].北京:中国建筑工业出版社,2009,12月
[45]唐必刚.基于Pushover (?)口能力谱法的桥梁结构抗震性能研究[D].长沙:湖南大学硕士论文,2010.
[46]候爽,欧进萍.结构Pushover分析的侧向力分布及高阶振型影响[J].地震工程与工程振动,2004,24(3):90-97.
[47]艾鹏.基于能量原理的通信单管塔P-△效应分析方法研究[D].武汉:武汉理工大学硕士论文,2007.
[48]《SAP2000中文版使用指南》.北京:人民交通出版社,2010:2.