桥梁风工程讲解课件.ppt

1、同济大学土木工程防灾国家重点实验室、桥梁工程系同济大学土木工程防灾国家重点实验室、桥梁工程系 桥梁与隧道工程专业硕士桥梁与隧道工程专业硕士生课程生课程主讲教师主讲教师：杨詠昕 副研究员博士副研究员博士同济大学同济大学土木工程防灾国家重点实验室土木工程防灾国家重点实验室桥梁工程系桥梁工程系 上课教材：公路桥梁抗风设计规范，2004年出版 参考资料：1.项海帆：现代桥梁抗风理论与实践 2.Simiu&Scanlan：风对结构的作用 3.李国豪：桥梁结构稳定与振动 上课方式：课堂讲课为主，结合风洞试验参观 授课讲义：可以自由拷贝 考试方式：实际桥梁抗风设计项目课程作业 上课时间：总共12讲，每讲3学

2、时 课程作业：6周左右时间，指导2次 上课地点：彰武校区北大楼403A室课程概况第一讲 桥梁风工程v 1.风工程u 1.1 风工程定义（J.E.Cermak）The rational treatment of interactions between wind and man and his engineered works on the surface of the earth.Applications of wind engineering are not for the most part aeronautical in nature,but are related to wind ef

3、fects on buildings,structures and pedestrians,short range transport of air pollutants and local wind modification by buildings,urban geometry and topography.u 1.2 风工程内容 A.结构风荷载压力或力*B.风振响应桥梁、结构、拉索、烟囱、塔桅等*C.局部风环境行人风环境、风冷因子(Wind-chill Factor)D.污染和其它元素扩散问题 E.风致运动物体飘移 F.建筑结构空气动力学通风、空气渗透、内部流动 G.气动现象车辆、船舶、

4、帆船、体育等 H.风能利用风力发电、场地选择 I.气象工程等u 1.3 风工程国际机构 .1963 Teddington,England .1967 Ottawa,Canada .1971 Tokyo,Japan(formally established).1975 Heathrow(London),England .1979 Fort Collin,Colorado,U.S.A .1983 Gold coast,Australia&Auckland,New Zealand A.ICWEInternational Conference on Wind Engineering.(Internat

5、ional Conference or Research Seminar on Wind E-ffects on Buildings and Structures)u 1.3 风工程国际机构(续)A.ICWEInternational Conference on Wind Engineering (International Conference or Research Seminar on Wind Effects on Buildings and structures)(续).1987 Aachen,F.R.Germany .1991 London,Qntario,Canada .1995

6、 New Delhi,India .1999 Copenhagen,Denmark .2003 Lubbock,Texas,U.S.A .2007 Cairns,Australia .2011 Amsterdam,Netherlandsu 1.3 风工程国际机构(续)B.IAWEInternational Association for Wind Engineering Established in 1975;By-Law Association since June 2003 Current President:Prof.Yukio Tamura Executive Committee:Sh

7、uyang Cao&Yaojun Ge(China)C.地区风工程协会 Asia-Pacific Region Secretary:Kenny Kwok(Hong Kong)Europe-Africa Region Secretary：James Baker(England)America Secretary：Ahsan Kareem(U.S.A)2001:5th Asia-Pacific Conference on Wind Engineering,Kyato,Japan 2005:6th Asia-Pacific Conference on Wind Engineering,Seoul,K

8、orea 2009:7th in Taiwan,Chinau 1.4 风工程国内机构A.中国空气动力学会 风工程与工业空气动力学委员会（四年，2006第七届）同济大学副主席（葛耀君）单位B.中国土木工程学会 结构风工程委员会（两年，2009年第十四届）同济大学主席（葛耀君）和秘书长（朱乐东）单位C.中国振动工程学会 结构动力学委员会（四年，2005年第四届）模态分析与实验委员会（四年，2005年第五届）2.风工程论著u 2.1 主要著作1.R.h.Scanlan E.Simiu,Wind Effects on Structures:An Introdu-ction to Wind Engine

9、ering,John Wiley&Sons,1996(3rd)2.P.Krishna,Recent Advances in Wind Engineering,Wiley Eastern Ltd.1994 3.H.Sockel,Wind-Excited Vibrations of Structures,Springer-Verlag,1994 4.A.Larsen,Aerodynamics of Large Bridges,Balkema,Rotteldam,1992 5.A.Larsen,Bridge Aerodynamics,Balkema,Rotterdam,1998 6.J.D-Holm

10、es,Wind Loading of Structures,Spon Press,London,2001 7.项海帆等，现代桥梁抗风理论与实践，人民交通出版社，2005 u 2.2 主要期刊1.Journal of Wind Engineering and Industrial Aerodynamics(previ-ously Journal of Industrial Aerodynamics).19752.Journal of Sound&Vibration 3.Journal of AIAA 4.Journal of Engineering Mechanics Division,ASCE

11、 5.Journal of Structural Engineering,ASCE 6.Journal of Fluid Mechanics 7.Journal of Wind and Structures,Korea u 2.3 知名专家A.加拿大 University of Western Ontario(UWO):(全世界公认第一座BLWT)Alan G.Davenport,Barry J.Vickery,Nicholas Isyumov David Surry,Peter King,Eric Ho,Horia Hangan National Research Council(NRC)&

12、University of Ottawa Robert I.Wardlaw,Hiroshi Tanaka,Kevin Cooper Steve Zan,Guy L.Larose RWDI Incoporation Inc.Peter Irwin,Michael J.Soligo,Jiming Xie u 2.3 知名专家(续)B.美国 Colorado State University Jack Cermak,R.N.Meroney John Hopkins University Nicholas Jones Texas Tech University Kishor Mehta,Xinzhon

13、g Chen University of Notre Dame Ahsan Kareem University of Lousiana Steve C.Cai C.印度 Prem Krishnau 2.3 知名专家(续)D.澳大利亚 Monashi University William Melbourne,John.Holmes,John ChengE.英国 Imperial College,Tom Wyatt University of Birmingham,James Baker F.德国 Hans-Jurgen Niemann G.丹麦 COWIAllan Larsen DMI Niel

14、s Franck H.意大利 University of Genoa,Giovanni Solari Politechico di Milano,G.Diana u 2.3 知名专家(续)I.日本 Tokyo Polytechnic University,Yukio Tamura Kyoto University,Masaru Matsumoto,H.Shirato University of Tokyo,Yozo Fujino,J.Kanda Yokohoma National University,Toshio Miyata,Hitoshi Yamada Keio University,S

15、huzo Murakami J.中国 同济大学土木工程防灾国家重点实验室 中国空气动力研究中心(绵阳)北京大学力学系、湍流国家重点实验室 西南交大桥梁工程系 汕头大学、湖南大学、长安大学 广东建科所、香港科技大学、香港理工大学 3.风工程历史u 3.1 平均风荷载(1760年)John Smeaton(17241792)伦敦皇家协会提出的风荷载计算公式21.2PV212DPVC1.96DC u 3.2 脉动风荷载(17601890年)1879年，Tay Bridge(75m铁桁架桥)风毁，列车上75人死亡 设计者：Thomas Bouch，风速 36m/s，CD=2.4 1889年，Eiffe

16、l Tower(300m铁塔)建造成功 设计者：Gustav Eiffel，阵风因子 1.41.7 加拿大 CN Tower 实测阵风因子1.7 1st Civil Engineer风毁年代风毁年代桥桥 名名国家国家跨径跨径(m)设计者设计者1818Dryburgh Abbey Bridge苏格兰79John&William Smith1821Union Bridge德国140Sir Samuel Brown1834Nassau Bridge英格兰75Lossen&Wolf1836Brighton Chair Pier Bridge英格兰80Sir Samuel Brown1838Montro

17、se Bridge苏格兰130Sir Samuel Brown1839Menai Straits Bridge威尔士180Thomas Telford1852Roche-Bernard Bridge法国195Le Blanc1854Wheeling Bridge美国310Charles Ellet1864Niagara-Lewiston Bridge美国320Edward Serrel1879Firth of Tay Bridge 苏格兰74Thomas Bouch1889Niagara-Clifton Bridge美国380Samuel Keeferu 3.2 脉动风荷载(续)脉动风荷载时代

18、遭风毁的桥梁u 3.3 气动稳定性(18901960年)November 7,1940,Tacoma Narrows Bridge 风毁录像。设计者：Leon Moisseiff,风速1822m/s。Prof.F.B.Farquharson,University of Washington.AThe bridge was found frequently doing vertical bending vibration in 1st and 2nd symmetric modes under very light wind of 3 to 6m/s.The maximum double amp

19、litude was said to be up to 0.6m and 0.8m in these modes,respectively.BOn the day of the final failure,the bridge oscillated for some hours in the 7th symmetric(f=0.60hz)and 8th asymmetric modes with wind of 18m/s to 22m/s.CWhen the wind speed was about 19m/s,suddenly the 1st asymmetric torsional mo

20、tion started(f=0.23hz)and became violent.Lateral motion also increased.The maximum torsional amplitude reached almost 450 before the disintegration of the structure started.u 3.3 气动稳定性(续)美国:von Karman,F.B.Farquharson,Fr.Bleich德国:K.Klppel挪威:A.Selberg日本:A.Hirai 英国:Kit Scruton 风致扭转振动 桥面折断坠落u 3.4 风荷载研究(

21、196020?)1960年:Alan G.Davenport 提出了风速统计和边界层 风洞模拟方法1982年:Alan G.Davenport 提出 W=Ws+Wd (ASCE Fall Convention)1990年:Alan G.Davenport 提出 Wind Loading Chain 4.风洞试验历史u 4.1 风洞风场 1879年:Tay Bridge 风毁，从无到有(静风压力)1940年:Tacoma Narrows Bridge风毁，从静到动(动风压力)1960年:A.G.Davenport 建立首座边界层风洞，从动到变u 4.2 缩尺模型 1936年:Prof.Nkken

22、tved第一次进行房屋模型风压实验。均匀流场 1945年:Nkkentved 和Irminger合作研究 1946年:Martin Jensen 主持风洞实验室 提出紊流场方法u 4.3 边界层风洞 50年代:Martin Jensen首次提出边界层风洞设想 60年代:A.G.Davenport 第一个实践边界层风洞（结构）60年代:Jack Cermak 也同时实践边界层风洞（环境）u 4.4 Davenport 对边界层风洞试验的贡献 A.The development of wind tunnel techniques simulating the atmospheric boundar

23、y layer flows.B.The development of fundamental aerodynamics on bluff bodies and the study of aero elastic behavior of structures.C.The adoption of statistical theories for the knowledge of atmospheric turbulence and structural dynamics and also in reliability theories.D.The development of instrument

24、ations-efficient measure-ment of flow,pressure,displacement,etc.5.风工程未来u 5.1 Prof.Davenport stated At the 5th Asia-Pacific Conference on Wind Engineering,August 2001.A.Cases Study Tacoma Narrows Bridge,Golden Gate Bridge,Ferrybridge cooling towers,Citicorp Buildings B.Reliability Basis This implies

25、a balance of accuracy and risk and the right emphasis for each link of the “wind loading chain”.C.Reynolds&Froude Number Effects Changes in stiffness,mass and damping in structures will lead to new requirements in dealing with wind effects.D.Climate Change Special consideration is needed to deal wit

26、h a variety of severe storms,hurricanes,tornadoes,downbursts,thunderstorms and blizzards.E.Surrounding Environment Topography,Buildings,etc.u 6.2 Prof.Scanlan stated(in his last words):“Observation on Low-Speed Aeroelasticity”An invited paper for 150th Anniversary of ASCE A.Full-Scale Reynolds Numbe

27、r Effects Proper duplication of full-scale Reynolds number effects is a practical impossibility.B.Equivalent Full-Scale Turbulence Proper realization of equivalent full-scale turbulence is also a practical impossibility小 结1.风工程范畴：定义、内容、机构等2.风工程论著：主要著作、主要期刊、知名专家等3.风工程历史：平均风荷载、脉动风荷载、气动稳定性等4.风洞试验历史：风洞风场、缩尺模型、边界层风洞等5.风工程未来：Davenport、Scanlan等预言