摘要
本文首先介绍了有关抗震分析的三种计算方法:反应谱法、时程分析法、随机振动法。然后为了研究和介绍大跨度桥梁的多点激励分析问题,基于时程分析理论,应用直接加速度法和大质量法,通过对两种简化模型的分析,探讨了空间变化效应对结构地震响应结果的影响;研究了激励输入模式、不同地震波、波速、几何非线性、波的输入方向等因素对地震响应的影响规律;基于大质量法的计算原理,在Midas/Civil有限元软件平台上实现了多点激励下大跨度桥梁的地震反应分析。讨论了行波效应和多点激励在结构抗震分析中的输入模式,主要探讨了大质量法的应用问题。分析结果表明:在地震激励下,边跨的关键点也可能成为大跨连续拱桥的控制点,在工程设计中应该引起重视。在不同地震激励模式作用下地震响应差别很大,尤其是行波效应可以改善固定墩受力,因此考虑三维地震、行波激励和多点激励更为合理。深入研究桥梁抗震性能对确保桥梁安全性尤为重要,本文以3跨连续下承式钢管混凝土系杆拱桥为工程背景,以大型有限元分析软件Midas/Civil为平台,对该桥进行地震反应分析。主要研究内容包括:
1.采用有限元分析软件Midas/Civil,通过适当简化建立了拱桥的结构模型,作为进行动力分析的基础,分析了拱桥的自振特性。
2.建立相应动力学方程来描述大跨度拱桥的动力性能,并选用适当的求解方法对问题进行求解。
3.选用经过幅值调整的天津波、Taft波和EI-Centro地震波三种加速度时程曲线,对拱桥空间有限元模型进行考虑几何非线性的一致激励、行波激励下的地震时程响应分析。
4.分别沿模型的纵向、纵向加横向及三维方向输入修正后的加速度曲线,进行了地震时程响应分析,得到了有限元模型对应控制截面的应力和位移响应。
5.考虑非一致激励行波效应,进行一致激励和非一致激励地震动加速度时程输入,对不同波速激励下地震时程反应进行对比分析,探讨了地震动空间变异性对大跨桥梁在地震作用下反应的影响。
6.采用反映地震动空间和时间变异性的人工地震波,对大跨拱桥空间有限元模型进行在一致激励、行波激励和多点激励下的地震时程反应分析,并比较了不同地震激励下时程分析结果,主要探讨了大质量法的应用问题。
Three methods of the seismic analysis, the response spectrum method, the time history method and the random vibration method, were introduced firstly. Based on the time history analysis theory, the direct acceleration method and the large-mass method were extended to make investigation to the multi-supported seismic analysis of long-span bridges.Two simplified models were extensively investigated to examine the spatial effects on the structural seismic responses. The effects of the primary factors such as excitation pattern, seismic waves, wave velocity, geonomic nonlinear and spreading direction of the earthquake wave and so on have been investigated. Based on the large-mass method, the seismic responses analysis of long-span bridges under multi-support excitation were realised on the platform of commercial finite element program Midas/Civil.The input mode of structure seismic analysis under traveling wave effect and multi-support excitations was discussed, and the application of the input of the large mass method was mainly researched.The calculated results reveal that the key points of side arch also may be the reference points of the long multi-span arch bridge under action of seismic excitation, which should be considered in engineering design. The seismic responses of the bridge varies greatly with different excitation patterns of earthquakes, especially traveling wave effect can improve fixed pier, so three-dimensional seismic wave, the travelling wave excitation and the multi-support excitation should be considered.It is necessary to make an indepth study and analysis to the seismic performance of these bridges, which is an important factor for safety.In this thesis, choosing a3-span continuous through concrete-filled steel tubular(CFST) tied-arch bridge as project background, carry out the seismic response with the finite element analysis software Midas/Civil.The study includs the following aspects:
1.The finite element model of the structure was built through reasonable simplification, and vibration mode were studied by using the famous program of Midas/Civil.
2.The corresponding dynamics equations were established to describe the bridge's dynamic actions while appropriate method was chosen to solve these equations.
3. Three acceleration time-history curves whose amplitudes have been adjusted including Tianjin wave, Taft wave and El-Centro wave were chosen to analyze seismic time-history response under the uniform excitation, the travelling wave excitation considering geometric nolinear by using three-dimension finite element model.
4.Inputing the modified acceleration time-history curve along longitudinal direction, longitudinal and transverse direction and3D direction, the internal force and displacement of the control sections are gained.
5. Taking non-consistent excitation travelling wave effeet into account, the consistent excitation and non-consistent excitation earthquake time-history acceleration were inputted, and the seismic reactions of the bridge under the different wave velocity were compared to explore the impact of the spatial variability of earthquake ground motions in large-span bridges.
6.The artificial waves involved in spatial and temporal variability were used to analyze seismic time-history response under the uniform excitation, the travelling wave excitation and multi-support excitation comparing results of different patterns of earthquake excitations by using three-dimension finite element model and the application of large mass method was mainly researched.
引文
[1]范立础.桥梁抗震.上海:同济大学出版社,1997,4-95
[2]沈昆.大跨连续拱桥地震响应分析:[长安大学硕士学位论文].西安,2010
[3]朱保华.矮塔斜拉桥的动力特性及地震响应分析:[西南交通大学硕士学位论文].成都,2008
[4]周飞秦.基于相位差谱的人工地震动拟合与桥梁地震响应分析:[中南大学硕士学位论文].长沙,2010
[5]颇晓芸.高墩大跨桥梁地震响应分析研究:[武汉理工大学硕士学位论文].武汉.2007
[6]李国豪.桥梁结构稳定与振动.北京:中国铁道出版社,2003,509-576
[7]谢礼力,罗学海.“国际减轻自然灾害十年”和地震研究的任务.地震工程与工程振动,1990,10(4):101-108
[8] Adanur S,Soyluk K, Bayraktar A et al. Stochastic SeismicResponse of the Bosporus Suspension Bridge to SpatiallyVarying Ground Motions. In: First EuroPean Conference onEarthquake Engineering and Seismology, lst ECEES,September3-8,2006:300, Geneva, Switzerland
[9] Lupoi A,Franchin P,Pinto P E,Monti G.. Seismic design ofbridges accounting for spatial variability of groundmotion.Earthquake Engineering and Struetural dynamics2005:34(4-5):327-348
[10]林家浩.随机地震响应的确定性算法,地震工程与工程振动,1985,5(l):89-94
[11]李正农,楼梦麟.大跨度桥梁结构地震动输入问题的研究现状同济大学学报,1999,27(5):592-597
[12]王一白.大跨度桥梁地震响应分析空间变化效应研究:[大连理工大学硕士学位论文].大连,2008
[13]邵长江.大跨度悬索拱桥地震响应分析:[西南交通大学硕士学位论文].成都,2003
[14]范立础,卓卫东.桥梁延性抗震设计.北京:人民交通出版社,2001,1-294
[15]范立础,王君杰,陈玮.非一致地震激励下大跨度斜拉桥的响应特征.计算力学学报,18(3):358-363
[16]程纬.随机地震动谱拟合模型及大跨度桥梁随机地震反应分析.[湖南大学博士学位论文].长沙,2000
[17]张亚辉,林家浩.香港青马桥抗震分析.应用力学学报,200219(3):25-30
[18]赵灿辉.大跨度钢管混凝土拱桥的地震响应研究.[西南交通大学博士学位论文].成都,2001
[19] Lin J.H.,Sun D.K.,Sun Y et al. Struetural responses tonon-uniformly modulated evolutionary random seismicexitations, Communications in numerical methods inengineering,1997, vol.13:605-616
[20] Loh C H,Lee S Z. Aseismic displacement analysis ofmulti-supported bridge to multiple excitations.Soil Dynamicsand Earthquake Engineering1990:9(1):25-33
[21] Nazmy Aly s,Abdel-Ghffor A M. Non-linear earthquake responseanalysis of lone-span cable-stayed bridges:Theory.EarthquakeEngineering&structural Dynamics,1990,19:45-62
[22] Yamamura N,Tanaka H. Response analysis of flexible MDF systemsfor multiple-support seismic excitations.EarthquakeEngineering and Struetural Dynamics,1990,19(3)345-357
[23] Venkataramana Katta,Kawano Kenji. Earthquake response ofmuti-span continuous bridges.Edited by Sociedad Mexicana deingenieria Sismica A C. Eleventh World Conference onEarthquake Engineering.Acapulco:Elsevier Science Ltd,1996
[24] Tubino F,Carassale L,Solari G.. Seismic response ofmulti-supported structures by proper orthogonaldecomposition.Earthquake Engineering and StructuralDynamics2003:32(11):1639-1654
[25] Kiureghian A D,Neuenhofer A. Response spectrum method formulti-support seismic excitations.Earthquake Engineeringand Struetural Dynamics,1992,21(8):713-740
[26] Zerva A. Response of multi-span beams to spatially incoherentseismic ground motions earthquake Engineering and StrueturalDynamics,1990:19(6):819-832
[27] Allam S M,Datta T K. Analysis of cable-stayed bridges undermulti-component random ground motion by response spectrummethod.Engineering Structures,2000,22(10):1367-1377
[28] Perrov A A. Seismic response of extended systems to multiplesupport excitations.Edited by Sociedad Mexicana deingenieria Sismica A C.Eleventh World Conference onEarthquake Engineering.Acapulco:Elsevier Science Ltd,1996
[29] Deodatis G,Saxena V,Shinozuka M. Effect of spatialvariability of ground motion on bridge fragility curves.In:Proceedings of the Eighth Specialty Conference onprobabilistic Mechanics and Structural Reliability2000:PMC2000-125,University of Notre Dame,Indiana
[30] Hao. H. Arch responses to correlated multiple eXcitations.Earthquake Engineering&Structural Dynamies,1993,22(3):389-404
[31]范立础,袁万城,胡世德.上海南浦大桥纵向地震反应分析.土木工程学报,1992,25(3):1-8
[32]陈幼平,周宏业.斜拉桥地震反应的行波效应.土木工程学报,1996,29(6):61-68
[33]李涛,阎贵平,李腾云等.上承式大跨度钢管混凝土拱桥的地震响应分析.北京交通大学学报,2005,29(1):4-8
[34]白玲.大跨度钢管混凝土拱桥地震响应分析.中国铁道科学,2008,29(6):41-44
[35]苏成,陈海斌.多点激励下大跨度桥梁的地震应.华南理工大学(自然科学版),2008,36(11):101-107
[36]陈海波.大跨度悬索桥考虑行波效应的地震分析.工程与建设,2010,24(4):500-502
[37]李忠献,黄健,丁阳等.不同地震激励下大跨度斜拉桥的地震反应分析.中国公路学报,2005,18(3):48-53
[38]刘爱荣,唐潘,禹奇才等.行波激励下大跨度拱桥随机地震响应分析.广州大学学报,2011,10(3):51-55
[39]王君杰,王前信.大跨度拱桥在空间变化地震动下的响应.振动工程学报,1995,8(2):119-126
[40]陈代海,郭文华.大跨度钢桁架拱桥的空间地震响应分析中南大学学报(自然科学版),2010,41(4):1590-1595
[41]史志利,李忠献.随机地震动场多点激励下大跨度桥梁地震反应分析方法.地震工程与工程振动,2003,23(4):124-130
[42]王成博,史志利,李忠献.随机地震动场多点激励下大跨度连续刚构桥的地震反应分析.地震工程与工程振动,2003,23(6):57-62
[43]刘爱荣,唐潘,禹奇才等.行波激励下大跨度拱桥随机地震响应分析.广州大学学报(自然科学版),2011,10(3):51-55
[44]韦晓,王君杰,袁万城等.桥梁抗震设计规范实用功率谱.同济大学学报,2000,28(1):98-102
[45]颇晓芸.高墩大跨桥梁地震响应分析研究:[武汉理工大学硕士学位论文].武汉,2007
[46]范立础.大跨度桥梁抗震.北京:人民交通出版社,2001
[47]苗家武.大型桥梁多点激励效应的研究现状与发展.同济大学学报,1999,27(2):189-193
[48]陈代海,郭文华.大跨度钢桁架拱桥的空间地震响应分析.中南大学学报(自然科学版),2010,41(4):1590-1596
[49]钟万勰.结构动力方程的精细时程积分法.大连理工大学学报,1994,34(2)
[50]屈铁军,王君杰,王前信.空间变化的地震动功率潜的实用模型.地震学报,1996,18(l):55-62
[51]周国良.河谷地形对多支撑大跨桥梁地震反应影响:[中国地震局工程力学研究所博士学位论文].哈尔滨,2010
[52] Leger P, Ide I M, Paultre P. Multiple-support seismic analysisof large structures. Computers&Structures,1990,36(6):1153-1158
[53]陈海斌.抗震分析中的多点激励问题.中国水运,2006,6(11):106-107
[54]谢旭.桥梁结构地震响应分析与抗震设计.北京:人民交通出版社,2006,17-112
[55]武董.超深水高墩桥梁的地震响应分析:[长安大学硕士学位论文].西安,2010
[56]钱冬生.大跨度悬索桥的设计与施工.西南交通大学出版社,1999,1-223
[57]王帽成,邵敏.有限单元法基本理论和数值方法.清华大学出版社,1997
[58] R.克拉夫,J.彭津.结构动力学.王光远,译.北京:高等教育出版社,2006,253
[59]孙广龙,宋建永,亓路宽等.大跨径钢筋混凝土拱桥的地震时程响应分析.公路交通科技,2007,24(3):86-89
[60]陆秉权,王立清,艾尚茂. Ansys动力分析中大质量法的应用.电站系统工程,2002,18(5):12
[61]王君杰.多点多维地震随机模型结构的反应谱分析方法:[博士学位论文].哈尔滨:国家地震工程力学研究所,1992
[62] O1iveira C S,Hao H,Penjien J. Ground motion modeling formultiple-input struetural analysis,Struetural Safety,1991,10:79-93
[63] SOYLUK K,DUMANOGLU A A. Spatial variability effects of groundmotions on cable-stayed bridges. Soil Dynamics and EarthquakeEngineering,2004,24(3):241-250
[64] Shengkui DI,Yong WEI,Zhonghu GAO. Impacts of BuffetingResponse of a Tied Thtough Arch Bridge Subjected to Excitationof Ribs under the Wind Load and Vertical Fluctuating Wind Load.In: Advances in Environmental Vibration. Beijing: SciencePress,2011:418-424
[65] Leger P,Ide I M,Paultre P. Multiple-support seismic analysisof large structures Computers&Structures,1990,36(6):1153-1158
[66]王波,张海龙,武修雄,等.基于大质量法的高墩大跨连续刚构桥地震时程反应分析[J].桥梁建设,2006(5):17-20.