大跨度斜拉桥施工阶段的抗风稳定性研究
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摘要
近年来,斜拉桥的跨径伴随着桥梁设计理论的逐步更新与新材料、新技术的不断涌现而取得了极大地发展,跨径大于1000m的斜拉桥逐渐增多。然而,跨径的增大也使得斜拉桥出现一系列新的问题,如桥梁施工时间的拉长、结构刚度的减小和稳定性的降低等。采用不同的施工方法造成斜拉桥结构体系在施工过程中的不断转换,最终使成桥后的状态受到影响。故影响斜拉桥设计和施工的一些因素变得越来越重要,尤其是斜拉桥的抗风稳定性。
斜拉桥施工阶段的抗风稳定性是一个很复杂的课题,其中静风稳定性、颤振、抖振、驰振等都会引起斜拉桥成桥后结构刚度及变形的变化。风致振动响应越大大,结构稳定性越差。只有深入系统的研究斜拉桥在施工状态的抗风稳定性后,才能安全顺利的对斜拉桥进行施工。以某长江大桥作为工程资料,本文使用由FORTRAN语言编写的BSNAA分析程序(桥梁结构三维非线性空气静力分析程序)及BSFA分析程序(桥梁结构颤振分析程序)和大型有限元软件MIDAS/Civil,对该桥施工过程中的关键阶段进行了空气静力、动力特征和空气动力稳定性等的研究,对比使用规范公式计算的结果,分析研究在施工过程中斜拉桥的抗风稳定性和动力特征的作用原理。
结果表明：随着施工的推进,桥梁主梁长度逐渐增加,(1)结构的静风失稳风速越来越小,在最大单悬臂阶段的静风失稳风速达到最小值；(2)在施工后期结构的自振频率下降幅度比施工前期的下降幅度小很多,即前期幅度较大。侧弯-扭转耦合振型在施工后期出现的次数增多。提高结构的竖弯频率可通过架设临时墩实现；(3)结构的颤振失稳风速越来越小,在成桥阶段属最不利状态。颤振稳定性可以通过边跨合龙和架设临时墩来提升；通过计算结果对比,在实际施工时使用规范公式计算得到的数值要比风洞试验结果小很多,故规范规定的计算方法具有更高的安全度。
Recently, the span of cable-stayed bridge have been greatly enlarged with the emergences of new materials and new construction technologies and refreshments of the bridge design theoies. Cable-stayed bridges with spans longer than1000m are becoming more and more. However, the increases of span length of cable-stayed bridges have caused a series of new problems, such as the increase of bridge construction time, the decrease of structural stiffness and of structural stability. Meantime, during the construction period, when different construction methods of are chosen,the bridge structural system is constantly changing which might eventually affect the final state of the bridge in completion. Thus some factors that will affect the design and construction of the cable-stayed bridge are becoming increasingly important, especially the wind stability of cable-stayed bridge.
The wind stability of constructing cable-stayed bridge is a quite complex subject, including aerostatic stability, flutter, buffeting and galloping. And each one of them can cause the decrease of structural stiffness and overall stability of cable-stayed bridge in completion, increase of structural deformation and wind-induced vibration response. In order to ensure the security of the construction process of cable-stayed bridge, further researches need to be done on the wind stability of cable-stayed bridge under construction. Based on a Yangtze River bridge and using large scale finite numerical simulation software MIDAS/Civil and BSNAA(BRIDGE STRUCTURE NONLINEAR AEROSTATIC ANASYSIS) and BSFA(BRIDGE STRUCTURE FLUTTER ANASYSIS) written by FORTRAN Language, this thesis has analysed aerostatic characteristics, dynamic characteristics and aerodynamic stability of the critical stages in the construction process of the bridge.And by comparing with the results calculated through methods that are used in realistic construction processes,this thesis reveals the dynamic characteristics and the variation and mechanism of the wind stability of constructing cable-stayed bridges.
The results show:as the construction progress continues,(1)the critical wind speed of aerostatic instability is becoming smaller and smaller with the lowest one at the maximum single cantilever stage;(2)the natural frequencies decrease slower in the later stages than the early stages.After the temporary piers are set,the vertical bending frequency increases remarkably. Many lateral-torsional coupled modes show up in the later stages;(3)the flutter critical wind speed is becoming lower and lower gradually with the lowest one in completion of the bridge. By completing the side spans and setting the temporary piers in side spans,the aerodynamic stability of the bridge under construction can be greatly improved;(4)compared with the results of wind tunnel test,the results calculated by the calculation method in Specification are much smaller which makes the calculation in Specification conservative.
斜拉桥施工阶段的抗风稳定性是一个很复杂的课题,其中静风稳定性、颤振、抖振、驰振等都会引起斜拉桥成桥后结构刚度及变形的变化。风致振动响应越大大,结构稳定性越差。只有深入系统的研究斜拉桥在施工状态的抗风稳定性后,才能安全顺利的对斜拉桥进行施工。以某长江大桥作为工程资料,本文使用由FORTRAN语言编写的BSNAA分析程序(桥梁结构三维非线性空气静力分析程序)及BSFA分析程序(桥梁结构颤振分析程序)和大型有限元软件MIDAS/Civil,对该桥施工过程中的关键阶段进行了空气静力、动力特征和空气动力稳定性等的研究,对比使用规范公式计算的结果,分析研究在施工过程中斜拉桥的抗风稳定性和动力特征的作用原理。
结果表明：随着施工的推进,桥梁主梁长度逐渐增加,(1)结构的静风失稳风速越来越小,在最大单悬臂阶段的静风失稳风速达到最小值；(2)在施工后期结构的自振频率下降幅度比施工前期的下降幅度小很多,即前期幅度较大。侧弯-扭转耦合振型在施工后期出现的次数增多。提高结构的竖弯频率可通过架设临时墩实现；(3)结构的颤振失稳风速越来越小,在成桥阶段属最不利状态。颤振稳定性可以通过边跨合龙和架设临时墩来提升；通过计算结果对比,在实际施工时使用规范公式计算得到的数值要比风洞试验结果小很多,故规范规定的计算方法具有更高的安全度。
Recently, the span of cable-stayed bridge have been greatly enlarged with the emergences of new materials and new construction technologies and refreshments of the bridge design theoies. Cable-stayed bridges with spans longer than1000m are becoming more and more. However, the increases of span length of cable-stayed bridges have caused a series of new problems, such as the increase of bridge construction time, the decrease of structural stiffness and of structural stability. Meantime, during the construction period, when different construction methods of are chosen,the bridge structural system is constantly changing which might eventually affect the final state of the bridge in completion. Thus some factors that will affect the design and construction of the cable-stayed bridge are becoming increasingly important, especially the wind stability of cable-stayed bridge.
The wind stability of constructing cable-stayed bridge is a quite complex subject, including aerostatic stability, flutter, buffeting and galloping. And each one of them can cause the decrease of structural stiffness and overall stability of cable-stayed bridge in completion, increase of structural deformation and wind-induced vibration response. In order to ensure the security of the construction process of cable-stayed bridge, further researches need to be done on the wind stability of cable-stayed bridge under construction. Based on a Yangtze River bridge and using large scale finite numerical simulation software MIDAS/Civil and BSNAA(BRIDGE STRUCTURE NONLINEAR AEROSTATIC ANASYSIS) and BSFA(BRIDGE STRUCTURE FLUTTER ANASYSIS) written by FORTRAN Language, this thesis has analysed aerostatic characteristics, dynamic characteristics and aerodynamic stability of the critical stages in the construction process of the bridge.And by comparing with the results calculated through methods that are used in realistic construction processes,this thesis reveals the dynamic characteristics and the variation and mechanism of the wind stability of constructing cable-stayed bridges.
The results show:as the construction progress continues,(1)the critical wind speed of aerostatic instability is becoming smaller and smaller with the lowest one at the maximum single cantilever stage;(2)the natural frequencies decrease slower in the later stages than the early stages.After the temporary piers are set,the vertical bending frequency increases remarkably. Many lateral-torsional coupled modes show up in the later stages;(3)the flutter critical wind speed is becoming lower and lower gradually with the lowest one in completion of the bridge. By completing the side spans and setting the temporary piers in side spans,the aerodynamic stability of the bridge under construction can be greatly improved;(4)compared with the results of wind tunnel test,the results calculated by the calculation method in Specification are much smaller which makes the calculation in Specification conservative.
引文
[1]陈政清.桥梁风工程,北京：人民交通出版社,2005
[2]文波.金江金沙江大桥斜拉桥动力特性分析[D].西南交通大学硕士学位论文,2005
[3]徐亚光.斜拉桥钢—混组合索塔锚固结构受力分析及模型试验研究[D].西南交通大学硕士学位论文,2010
[4]董玲珑.超大跨度斜拉桥施工全过程抗风稳定性研究[D].浙江工业大学硕士学位论文,2009
[5]项海帆,葛耀君,陈艾荣等著.现代桥梁抗风理论与实践[M].北京：人民交通出版社,2005
[6]吴立斌.大跨度悬索桥施工过程抗风稳定性研究[D].浙江工业大学硕士学位论文,2009
[7]官万轶.斜拉桥施工过程的预测与控制方法研究[D].华南理工大学博士论文,2000
[8]JTG/TD60.01.2004公路桥梁抗风设计规范
[9]R. H. Scanlan and A. Sabzevari. Suspension bridge flutter,revisited Preprint No.468. ASCE National Meeting on Structural Engineering, Seattle, May,1967
[10]李程.斜拉桥的发展现状与趋势[M].辽宁经济,2009
[11]T. Miyata and H. Yamada. Coupled flutter estimate of a suspension bridge[J]. JWEIA, 1990,33(1&2):341-348
[12]N. N. Dung,T. Miyata, H. Yamada. dt al. Flutter responses in long span bridge with wind induced displacement by the mode tracing method[J]. Journal of Wind EngineefingAnd Industrial Aerodynamics.1998,78-79:367-379
[13]YJ. Ge and H. Tamada. Aerodynamic flutter analysis of cable-supposed bridges by multi-mode and full-mode approaches [J], Joumal of Wind Engineering and Industrial Aerodynamics 2000,86,123-153
[14]T. J. A. Agar. Aerodynamic flutter analysis of suspension bridges by a model technique[J]. Journal ofEngineering Structures 1989, (11):75-82
[15]Ahmnad Namini,Pedro Albrecht. Finite Dement.based Flutter Analysis of Cable-suspended Bridges[J]. Struct. Engrg,1992.118(6):1509-1525
[16]Davenport A G Buffeting of a Suspension Bridge by Storm Winds[J]. Struct. Div,Reproccedings of the American Society of Civil Engillcers,1962, 88(3):233-267
[17]Buche C G Llin Y K. Stochastic Stability of Bridges Corlsidering Coupled Modes. I, II[J]. Engre. Mcch.1988,114(12):2055-2071
[18]项海帆,刘春华.大跨度桥梁耦合抖振响应的时域分析[N].同济大学学报,1996,24(4)：380-385
[19]刘天伟.大跨度斜拉桥的动、静力性能分析[D].合肥工业大学硕士论文,2010
[20]王伯惠编著.斜拉桥结构发展和中国经验[M].北京：人民交通出版社,2003
[21]R. H. Scanlan. Bridge deck aeroelastic admittance revisited. Journal of bridge Engineering[J]. v01.5(1):1N7
[22]DavenportAO. Buffeting ofa suspension bridge by storm winds [J]. Journal of Structural Division, ASCE,1962, (ST3):233-268
[23]Jain A, Jones N P'Scanlan R H, Coupled aeroelastic and aerodynamic response analysis of long-span bridges[J]. Wind. Eng. Ind. Aerodyn,1996,(60):69-80
[24]胡晓伦.大跨度斜拉桥颤抖振响应及静风稳定性分析,同济大学博士学位论文[D].2006
[25]刘春华.大跨度桥梁抖振响应的非线性时程分析,同济大学博士学位论文[D].2005
[26]曹映泓.大跨度桥梁非线性颤振和抖振时程分析,同济大学博士学位论文[D].1999
[27]张新军.大跨径桥梁三维非线性颤振分析,同济大学博士学位论文[D].2000
[28]蒋永林.斜拉桥抖振响应分析,西南交通大学博士学位论文[D].2000年
[29]李永乐.风车桥系统非线性空间耦合振动研究,西南交通大学博士学位论文[D].2003
[30]丁泉顺,大跨度桥梁耦合颤抖振响应的精细化分析,同济大学博士学位论文[D].2001
[31]邹小江.斜拉桥风振响应时域分析及静风稳定性研究,华南理工大学博士学位论文[D].2003
[32]张志田.大跨度桥梁非线性抖振及其对抗风稳定性影响的研究,同济大学博士学位论文[D].2004
[33]曹丰产.桥梁气动弹性问题的数值计算,同济大学博士学位论文[D].1999
[34]陈艾荣等著.苏通长江公路大桥结构抗风性能分析与试验研究(之二)主桥结构动力特性分析与风荷载计算[R].上海,同济大学土木工程防灾国家重点实验室,2003.
[35]李国豪.桥梁结构稳定与振动[M].北京：中国铁道出版社,1992.
[36]范立础.桥梁抗震[M].上海：同济大学出版社,1997.
[37]李国豪.结构工程抗震动力学[M].北京：中国铁道出版社,1980.
[38]陈淮等.大跨度斜拉桥动力特性分析[J].计算力学学报,1997,14(1)：57·63
[39]陈仁福.大跨度悬索桥理论[M].成都：西南交通大学出版社,1994.
[40]Toshio Migata, Hitoshi Yamada. Aerodynamics of Wind Effects on Long. Span Cable SuppoSed Bridges[A]. Innovative Large Span Structures[C].1ASS CSCE International Congress. Toronto,1992.
[41]方明山.超大跨度缆索承重桥梁非线性空气静力稳定性理论研究[D].同济大学博士学位论文,1997
[42]陈光华.斜拉桥发展现状与发展趋势[M].山西建筑,2008
[43]金晶.斜拉桥静动力有限元分析[D].合肥工业大学硕士论文.2009
[44]Simiu. E, Scanlan. R. H. Wind Effects on Structures,3-ED[M]. John Wiley&Sons, New York,1996
[45]刘光栋,罗汉泉.杆系结构稳定[M].北京：人民交通出版社,1994
[46]何君毅,林祥.工程结构非线性问题的数值解法[M].北京：国防工业出版社,1994
[47]Seiichiro Fukushima. Dynamic Characteristics of Cable Structures Under Vertical Excitation[A]. Innovative Large Span Structures[C].1ASS CSCE International Congress.Toronto,1992.
[48]张新军.缆索承重桥梁颤振稳定性研究[D].浙江大学博士后学位论文,2003
[49]程进.缆索承重桥梁非线性空气静力稳定性研究[D].同济大学博士学位论文,2000
[50]张朝斌.大跨度悬索桥施工过程抗风稳定性研究[D].浙江工业大学硕士论文,2009
[51]孟松兔,张新军,刘相玉.大跨径斜拉桥空气动力稳定性的参数研究[J].公路,2003,(7)：123-125
[52]葛耀君.大跨度桥梁耦合颤抖振响应的精细化分析,同济大学博士学位论文[D],1997
[2]文波.金江金沙江大桥斜拉桥动力特性分析[D].西南交通大学硕士学位论文,2005
[3]徐亚光.斜拉桥钢—混组合索塔锚固结构受力分析及模型试验研究[D].西南交通大学硕士学位论文,2010
[4]董玲珑.超大跨度斜拉桥施工全过程抗风稳定性研究[D].浙江工业大学硕士学位论文,2009
[5]项海帆,葛耀君,陈艾荣等著.现代桥梁抗风理论与实践[M].北京：人民交通出版社,2005
[6]吴立斌.大跨度悬索桥施工过程抗风稳定性研究[D].浙江工业大学硕士学位论文,2009
[7]官万轶.斜拉桥施工过程的预测与控制方法研究[D].华南理工大学博士论文,2000
[8]JTG/TD60.01.2004公路桥梁抗风设计规范
[9]R. H. Scanlan and A. Sabzevari. Suspension bridge flutter,revisited Preprint No.468. ASCE National Meeting on Structural Engineering, Seattle, May,1967
[10]李程.斜拉桥的发展现状与趋势[M].辽宁经济,2009
[11]T. Miyata and H. Yamada. Coupled flutter estimate of a suspension bridge[J]. JWEIA, 1990,33(1&2):341-348
[12]N. N. Dung,T. Miyata, H. Yamada. dt al. Flutter responses in long span bridge with wind induced displacement by the mode tracing method[J]. Journal of Wind EngineefingAnd Industrial Aerodynamics.1998,78-79:367-379
[13]YJ. Ge and H. Tamada. Aerodynamic flutter analysis of cable-supposed bridges by multi-mode and full-mode approaches [J], Joumal of Wind Engineering and Industrial Aerodynamics 2000,86,123-153
[14]T. J. A. Agar. Aerodynamic flutter analysis of suspension bridges by a model technique[J]. Journal ofEngineering Structures 1989, (11):75-82
[15]Ahmnad Namini,Pedro Albrecht. Finite Dement.based Flutter Analysis of Cable-suspended Bridges[J]. Struct. Engrg,1992.118(6):1509-1525
[16]Davenport A G Buffeting of a Suspension Bridge by Storm Winds[J]. Struct. Div,Reproccedings of the American Society of Civil Engillcers,1962, 88(3):233-267
[17]Buche C G Llin Y K. Stochastic Stability of Bridges Corlsidering Coupled Modes. I, II[J]. Engre. Mcch.1988,114(12):2055-2071
[18]项海帆,刘春华.大跨度桥梁耦合抖振响应的时域分析[N].同济大学学报,1996,24(4)：380-385
[19]刘天伟.大跨度斜拉桥的动、静力性能分析[D].合肥工业大学硕士论文,2010
[20]王伯惠编著.斜拉桥结构发展和中国经验[M].北京：人民交通出版社,2003
[21]R. H. Scanlan. Bridge deck aeroelastic admittance revisited. Journal of bridge Engineering[J]. v01.5(1):1N7
[22]DavenportAO. Buffeting ofa suspension bridge by storm winds [J]. Journal of Structural Division, ASCE,1962, (ST3):233-268
[23]Jain A, Jones N P'Scanlan R H, Coupled aeroelastic and aerodynamic response analysis of long-span bridges[J]. Wind. Eng. Ind. Aerodyn,1996,(60):69-80
[24]胡晓伦.大跨度斜拉桥颤抖振响应及静风稳定性分析,同济大学博士学位论文[D].2006
[25]刘春华.大跨度桥梁抖振响应的非线性时程分析,同济大学博士学位论文[D].2005
[26]曹映泓.大跨度桥梁非线性颤振和抖振时程分析,同济大学博士学位论文[D].1999
[27]张新军.大跨径桥梁三维非线性颤振分析,同济大学博士学位论文[D].2000
[28]蒋永林.斜拉桥抖振响应分析,西南交通大学博士学位论文[D].2000年
[29]李永乐.风车桥系统非线性空间耦合振动研究,西南交通大学博士学位论文[D].2003
[30]丁泉顺,大跨度桥梁耦合颤抖振响应的精细化分析,同济大学博士学位论文[D].2001
[31]邹小江.斜拉桥风振响应时域分析及静风稳定性研究,华南理工大学博士学位论文[D].2003
[32]张志田.大跨度桥梁非线性抖振及其对抗风稳定性影响的研究,同济大学博士学位论文[D].2004
[33]曹丰产.桥梁气动弹性问题的数值计算,同济大学博士学位论文[D].1999
[34]陈艾荣等著.苏通长江公路大桥结构抗风性能分析与试验研究(之二)主桥结构动力特性分析与风荷载计算[R].上海,同济大学土木工程防灾国家重点实验室,2003.
[35]李国豪.桥梁结构稳定与振动[M].北京：中国铁道出版社,1992.
[36]范立础.桥梁抗震[M].上海：同济大学出版社,1997.
[37]李国豪.结构工程抗震动力学[M].北京：中国铁道出版社,1980.
[38]陈淮等.大跨度斜拉桥动力特性分析[J].计算力学学报,1997,14(1)：57·63
[39]陈仁福.大跨度悬索桥理论[M].成都：西南交通大学出版社,1994.
[40]Toshio Migata, Hitoshi Yamada. Aerodynamics of Wind Effects on Long. Span Cable SuppoSed Bridges[A]. Innovative Large Span Structures[C].1ASS CSCE International Congress. Toronto,1992.
[41]方明山.超大跨度缆索承重桥梁非线性空气静力稳定性理论研究[D].同济大学博士学位论文,1997
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