大跨人行悬索桥非线性静风失稳发展过程分析
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摘要
为研究大跨人行悬索桥非线性静风失稳的内在原因,以主跨420m天蒙人行悬索桥为背景进行分析。综合考虑几何非线性与静风荷载非线性,采用内、外双重迭代算法从定性与定量的角度分析该桥非线性静风失稳发展过程及失稳临界形态。结果表明:大跨人行悬索桥静风失稳发展路径为,不断非线性增大的加劲梁位移牵连主缆和抗风缆产生相对于加劲梁的竖向位移,使主缆和抗风缆逐渐消减拉应力,直至抗风缆接近松弛而失稳;静风失稳临界形态是以加劲梁扭转变形为主、竖弯变形为辅的复杂弯-扭耦合空间变形状态;静风失稳内在原因为,静风升力和升力矩随附加风攻角的增长不断增大,加劲梁和缆索系统的静风位移持续增大并产生相对竖向位移,导致缆索系统刚度大幅卸载。
To study the inherent causes of the nonlinear aerostatic instability of long span pedestrian suspension bridge,the Tianmeng Pedestrian Suspension Bridge having a main span of 420 m was taken as an analysis object and comprehensively considering the geometric nonlinearity and the aerostatic load nonlinearity,the inner and outer double iteration algorithm was used to qualitatively and quantitatively analyze the development process of the nonlinear aerostatic instability and the critical state of the aerostatic instability of the bridge.The results of the analysis reveal that the development path of the aerostatic instability of the long span pedestrian suspension bridge is that the nonlinearly increasing displacement of the stiffening girder of the bridge causes the main cables and wind cables to have the vertical displacement that is relative to the girder,makes the tensile stresses of the cables gradually reduce and until the wind cables approach to the relaxation,causes the aerostatic instability to occur.The critical state of the aerostatic instability is the spatial deformation state of the complex bending and torsion coupling characterized mainly by the torsion deformation and secondarily by the vertical bending deformation of the girder.The inherent causes of the aerostatic instability are the aerostatic lift and the incessant increase of the lift moment changing with the increase of the additional wind attack angles.The incessant increase of the aerostatic displacement of the girder and the cable systems and the produced relative vertical displacement all results in the great unloading rigidity of the cable systems.
To study the inherent causes of the nonlinear aerostatic instability of long span pedestrian suspension bridge,the Tianmeng Pedestrian Suspension Bridge having a main span of 420 m was taken as an analysis object and comprehensively considering the geometric nonlinearity and the aerostatic load nonlinearity,the inner and outer double iteration algorithm was used to qualitatively and quantitatively analyze the development process of the nonlinear aerostatic instability and the critical state of the aerostatic instability of the bridge.The results of the analysis reveal that the development path of the aerostatic instability of the long span pedestrian suspension bridge is that the nonlinearly increasing displacement of the stiffening girder of the bridge causes the main cables and wind cables to have the vertical displacement that is relative to the girder,makes the tensile stresses of the cables gradually reduce and until the wind cables approach to the relaxation,causes the aerostatic instability to occur.The critical state of the aerostatic instability is the spatial deformation state of the complex bending and torsion coupling characterized mainly by the torsion deformation and secondarily by the vertical bending deformation of the girder.The inherent causes of the aerostatic instability are the aerostatic lift and the incessant increase of the lift moment changing with the increase of the additional wind attack angles.The incessant increase of the aerostatic displacement of the girder and the cable systems and the produced relative vertical displacement all results in the great unloading rigidity of the cable systems.
引文
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[3]Virote Boonyapinyo,Yingsak Lauhatanon,Panitan Lukkunaprasit.Nonlinear Aerostatic Stability Analysis of Suspension Bridges[J].Engineering Structures,2006,28(5):793-803.
[4]方明山,项海帆,肖汝诚.大跨径缆索承重桥梁非线性空气静力稳定理论[J].土木工程学报,2000,33(2):73-79.(FANG Ming-shan,XIANG Hai-fan,XIAO Rucheng.Nonlinear Aerostatic Stability Theory of LargeSpan Cable-Stayed Bridges[J].China Civil Engineering Journal,2000,33(2):73-79.in Chinese)
[5]ZHANG Zhi-tian,GE Yao-jun,YANG Yong-xin.Torsional Stiffness Degradation and Aerostatic Divergence of Suspension Bridge Decks[J].Journal of Fluids and Structures,2013,40:269-283.
[6]张志田,张伟峰.悬索桥在紊流风场中的静风扭转发散机制[J].土木工程学报,2013,46(7):74-80.(ZHANG Zhi-tian,ZHANG Wei-feng.Mechanism of the Aerostatic Torsional Divergence of Suspension Bridges in Turbulent Flows[J].China Civil Engineering Journal,2013,46(7):74-80.in Chinese)
[7]SU Cheng,LUO Xiu-feng,YUN Tian-quan.Aerostatic Reliability Analysis of Long-Span Bridges[J].Journal of Bridge Engineering,2010,15(3):260-268.
[8]张文明,王溧,刘钊.基于应变能的三塔悬索桥静风失稳形态分析[J].桥梁建设,2013,43(5):62-67.(ZHANG Wen-ming,WANG Li,LIU Zhao.Analysis of Aerostatic Instability Mode of a Three-Tower Suspension Bridge Based on Strain Energy[J].Bridge Construction,2013,43(5):62-67.in Chinese)
[9]ZHANG Xin-jun.Numerical Investigation on the Wind Stability of Super Long-Span Partially Earth-Anchored Cable-Stayed Bridges[J].Wind and Structures,2015,21(4):407-424.
[10]李永乐,侯光阳,乔倩妃,等.超大跨径悬索桥主缆材料对静风稳定性的影响[J].中国公路学报,2013,26(4):72-77.(LI Yong-le,HOU Guang-yang,QIAO Qian-fei,et al.Effects of Different Main Cable Materials on Aerostatic Stability of Super-Long-Span Suspension Bridges[J].China Journal of Highway and Transport,2013,26(4):72-77.in Chinese)
[11]李加武,方成,侯利明,等.大跨径桥梁静风稳定参数的敏感性分析[J].振动与冲击,2014,33(4):124-130.(LI Jia-wu,FANG Cheng,HOU Li-ming,et al.Sensitivity Analysis for Aerostatic Stability Parameters of a Long-Span Bridge[J].Journal of Vibration and Shock,2014,33(4):124-130.in Chinese)
[12]万田保.张家界大峡谷异型玻璃悬索桥设计关键技术[J].桥梁建设,2017,47(1):6-11.(WAN Tian-bao.Key Techniques of Design of Special Shape Glass Floor Suspension Bridge over Zhangjiajie Grand Canyon[J].Bridge Construction,2017,47(1):6-11.in Chinese)