斜拉索在随机风-车-覆冰联合作用下的疲劳可靠度分析
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摘要
为了分析随机风-车荷载及覆冰联合作用下的斜拉索的疲劳可靠度,以武汉天兴洲长江大桥为工程背景进行研究。首先,根据Monte Carlo法组成随机车队,模拟随机车辆荷载谱,将车辆模型转化为节点动力荷载输入斜拉桥模型中,通过谐波叠加法生成风速时程,将风荷载引起的静风力、抖振力、气动自激力施加到斜拉桥模型中;然后,依据横风向驰振理论,考虑扇形索覆冰引起的自激振动影响,采用Fluent软件模拟拉索在覆冰状态下的升力系数,求出30°风攻角下的升力并施加到拉索上,将拉索计算出的时程力施加到对应的主梁模拟点上;最后,基于累积损伤理论,分别对斜拉桥在单一车荷载、风-车荷载联合作用及风-车-覆冰联合作用下拉索的疲劳可靠度进行分析,得到拉索的疲劳可靠度指标。研究结果表明:风-车荷载联合作用下拉索的疲劳可靠度指标明显低于单一随机车荷载作用下的疲劳可靠度指标,最短索的疲劳可靠度指标降低了约21%;覆冰会降低拉索的疲劳可靠度指标,但其降低幅度不大,考虑到覆冰作用引起的最大索力大于其他2种工况的最大索力,其影响不能忽略;风荷载对拉索的疲劳可靠度影响显著,且随着拉索长度增大,影响也逐渐增大。该方法主要是将荷载以节点动力荷载的形式施加到桥面模拟点上,因此该方法同样适用于其他桥梁的疲劳可靠度分析。
To analyze the fatigue reliability of stay cables under the combined effects of random wind load, vehicle load, and ice accretion, the Tianxingzhou Yangtze River Bridge was considered as the engineering background for specific research. First, the load spectrum of a random vehicle was simulated according to the Monte Carlo method. The vehicle model was transformed into the model of node dynamic load input cable-stayed bridge. The time history of wind speed was generated through the harmonic superposition method. The static wind force, buffeting force, and aerodynamic auto-excited force due to wind load were applied to the model. The horizontal wind galloping effect of fan-shaped iced accretion cable was then considered using the principle of auto-excited vibration. Fluent software was used to simulate the lift coefficient in the ice accretion cable. The lift was applied to the cable at an angle of 30°. The time history of the cable when applied to the corresponding simulated point girders was observed. Finally, based on the cumulative damage theory for cable-stayed bridge in random vehicle load, the combined effect of random wind-vehicle load and iced accretion under the fatigue reliability of cable was analyzed to obtain the fatigue reliability index of the cable. The results show that the fatigue reliability index of the cable under the combined effects of wind load and vehicle load is less than that under single random vehicle load. The fatigue reliability index of the shortest cable decreased by approximately 21%. Iced accretion had minimal effect on the fatigue reliability index. Considering that the maximum force caused by the iced accretion is greater than the maximum force of the other two cases, the effect cannot be ignored. The effect of wind load on fatigue reliability is significant. The degree of influence increased from short to long cables. This method is mainly to load in the form of a node dynamic load applied to the bridge deck simulation point. Therefore, the proposed method can also be applied to the fatigue reliability analysis of other bridges.
To analyze the fatigue reliability of stay cables under the combined effects of random wind load, vehicle load, and ice accretion, the Tianxingzhou Yangtze River Bridge was considered as the engineering background for specific research. First, the load spectrum of a random vehicle was simulated according to the Monte Carlo method. The vehicle model was transformed into the model of node dynamic load input cable-stayed bridge. The time history of wind speed was generated through the harmonic superposition method. The static wind force, buffeting force, and aerodynamic auto-excited force due to wind load were applied to the model. The horizontal wind galloping effect of fan-shaped iced accretion cable was then considered using the principle of auto-excited vibration. Fluent software was used to simulate the lift coefficient in the ice accretion cable. The lift was applied to the cable at an angle of 30°. The time history of the cable when applied to the corresponding simulated point girders was observed. Finally, based on the cumulative damage theory for cable-stayed bridge in random vehicle load, the combined effect of random wind-vehicle load and iced accretion under the fatigue reliability of cable was analyzed to obtain the fatigue reliability index of the cable. The results show that the fatigue reliability index of the cable under the combined effects of wind load and vehicle load is less than that under single random vehicle load. The fatigue reliability index of the shortest cable decreased by approximately 21%. Iced accretion had minimal effect on the fatigue reliability index. Considering that the maximum force caused by the iced accretion is greater than the maximum force of the other two cases, the effect cannot be ignored. The effect of wind load on fatigue reliability is significant. The degree of influence increased from short to long cables. This method is mainly to load in the form of a node dynamic load applied to the bridge deck simulation point. Therefore, the proposed method can also be applied to the fatigue reliability analysis of other bridges.
引文
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[12] 殷志祥,高哲,冯瑶.车辆荷载作用下斜拉索疲劳可靠度分析[J].工业建筑,2017,47(6):163-167. YIN Zhi-xiang,GAO Zhe,FENG Yao.Fatigue reliability analysis of cable of cable-stayed bridge under vehicle loads[J].Industrial Construction,2017,47(6):163-167.
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[15] 谭冬梅,王凯丽.三维覆冰斜拉索风致振动驰振分析[J].振动与冲击,2016,35(7):157-160. TAN Dong-mei,WANG Kai-li.Galloping analysis of wind-induced vibration for 3D stay cables with iced accretion[J].Journal of Vibration and Shock,2016,35(7):157-160.
[16] 李杨海,鲍卫刚,郭修云,等.公路桥梁结构可靠度与概率极限状态设计[M].北京:人民交通出版社,1997. LI Yang-hai,BAO Wei-gang,GUO Xiu-yun,et al.The design of highway bridge structure reliability and the probability limit state[M].Beijing:China Communications Press,1997.
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[19] 曹素功.风和列车荷载作用下大跨桥梁动力分析[D].湘潭:湘潭大学,2014. CAO Su-gong.Dynamic analysis of long-span bridge subjected to wind and train[D].Xiangtan:Xiangtan University,2014.
[20] DEN HARTOG J P.Transmission line vibration due to sleet[J].Transactions of the American Institute of Electrical Engineers,1932,51:1074-1077.
[21] 腾二甫,段忠东,张秀华.新月形覆冰导线气动力特性的数值模拟[J].低温建筑技术,2008(1):86-88. TENG Er-fu,DUAN Zhong-dong,ZHANG Xiu-hua.Numerical simulations of aerodynamic characteristics of iced conduct or with crescent shape[J].Low Temperature Architecture Technology,2008(1):86-88.
[22] 曾超.刚桥构件按疲劳寿命服从威布尔分布的可靠度计算[J].西南交通大学学报,1993,28(5):20-23. ZENG Chao.The reliability of fatigue life for steel bridge components by Weibull distribution[J].Journal of Southwest Jiaotong University,1993,28(5):20-23.
[23] IEC.Maritime navigation and radio communication equipment and systerms-shipborne radar-Performance requirements,methods of testing and required test results[R].Geneva:IEC,2007.
[24] 程高,刘永健,张俊光,等.基于Monte Carlo法的多车道公路桥梁车流模拟[J].重庆交通大学学报:自然科学版,2011,30(6):1375-1378. CHENG Gao,LIU Yong-jian,ZHANG Jun-guang,et al.Traffic flow simulation of multi-lane highway bridge based on Monte Carlo method[J].Journal of Chongqing Jiaotong University:Natural Science Edition,2011,30(6):1375-1378.
[25] 张茜,周绪红,狄谨,等.大跨度钢箱梁斜拉桥施工过程风致抖振时域分析及抗风措施[J].长安大学学报:自然科学版,2013,33(1):45-66. ZHANG Qian,ZHOU Xu-hong,DI Jin.Time-domain analysis of wind-induced buffet and win-resistant measures for cable-stayed bridge with steel box girder at construction on stage[J].Journal of Chang’an University:Natural Science Edition,2013,33(1):45-66.
[2] SETRA.Cable stays recommendations of French interministerial commission on prestressing[S].
[3] FABER M H,ENGELUND S,RACKWITZ R.Aspects of parallel wire cable reliability[J].Structural Safety,2003,25(2):201-225.
[4] CREMONA C.Probabilistic approach for cable residual strength assessment[J].Engineering Structures,2003,25(3):377-384.
[5] ZHANG J,AU F T K.Fatigue reliability assessment considering traffic flow variation based on weigh-in-motion data[J].Advances in Structural Engineering,2017,20(1):125-138.
[6] ALDUSE B P,JUNG S,VANLI O A,et al.Effect of uncertainties in wind speed and direction on the fatigue damage of long-span bridges[J].Engineering Structures,2015,100:468-478.
[7] 李春祥,李薇薇.斜拉索风致振动疲劳的分析[J].振动与冲击,2009,28(9):135-138. LI Chun-xiang,LI Wei-wei.Analysis of wind-induced fatigue of inclined cable[J].Journal of Vibration and Shock,2009,28(9):135-138.
[8] 李春祥,李薇薇.斜拉索风致动力疲劳损伤的研究[J].振动与冲击,2009,28(11):61-66. LI Chun-xiang,LI Wei-wei.Analysis of wind-induced fatigue damage of inclined cable[J].Journal of Vibration and Shock,2009,28(11):61-66.
[9] 谭冬梅,陈杰,瞿伟廉.用于大跨斜拉桥拉索疲劳可靠度分析荷载的研究[J].武汉理工大学学报,2015,37(6):54-59. TAN Dong-mei,CHEN Jie,QU Wei-lian.Study on load for fatigue reliability analysis of cables of large-span cable-stayed bridge[J].Journal of Wuhan University of Technology,2015,37(6):54-59.
[10] 王贵春,李武生.斜拉桥在多车辆作用下的动力响应分析[J].桥梁建设,2014,44(6):81-87. WANG Gui-chun,LI Wu-sheng.Analysis of dynamic responses of cable-stayed bridge under action of multiple vehicles[J].Bridge Construction,2014,44(6):81-87.
[11] 杨晓艳,贡金鑫,张启伟.随机车辆荷载作用下斜拉索索力的概率模型及可靠度分析[J].建筑科学与工程学报,2014,31(2):90-98. YANG Xiao-yan,GONG Jin-xin,ZHANG Qi-wei.Analysis of probabilistic model of stay cable stress reliability under random vehicle loads[J].Journal of Arichitecture and Civil Engineering,2014,31(2):90-98.
[12] 殷志祥,高哲,冯瑶.车辆荷载作用下斜拉索疲劳可靠度分析[J].工业建筑,2017,47(6):163-167. YIN Zhi-xiang,GAO Zhe,FENG Yao.Fatigue reliability analysis of cable of cable-stayed bridge under vehicle loads[J].Industrial Construction,2017,47(6):163-167.
[13] 李岩,吕大刚,盛洪飞.考虑随机车载-风载联合作用下部分斜拉索疲劳可靠度研究[J].中国公路学报,2012,25(2):60-66. LI Yan,LU Da-gang,SHENG Hong-fei.Fatigue reliability analysis on cable of cable-stayed bridge under random vehicle load and wind load[J].China Journal of Highway and Transport,2012,25(2):60-66.
[14] 甘凤林,马涛,黄金花.导线覆冰对架空输电线路结构的影响[J].华北电力技术,2008,24(8):84-86. GAN Feng-lin,MA Tao,HUANG Jin-hua.Influence of conductor ice coating on transmission line structure[J].North China Elector IC Power,2008,24(8):84-86.
[15] 谭冬梅,王凯丽.三维覆冰斜拉索风致振动驰振分析[J].振动与冲击,2016,35(7):157-160. TAN Dong-mei,WANG Kai-li.Galloping analysis of wind-induced vibration for 3D stay cables with iced accretion[J].Journal of Vibration and Shock,2016,35(7):157-160.
[16] 李杨海,鲍卫刚,郭修云,等.公路桥梁结构可靠度与概率极限状态设计[M].北京:人民交通出版社,1997. LI Yang-hai,BAO Wei-gang,GUO Xiu-yun,et al.The design of highway bridge structure reliability and the probability limit state[M].Beijing:China Communications Press,1997.
[17] BERGMEISTER K,SANTA U.Global monitoring concepts for bridges[J].Structural Concrete,2001,2(1):29-39.
[18] 项海帆.现代桥梁抗风理论与实践[M].北京:人民交通出版社,2005. XIANG Hai-fan.Mondern theory and practice on bridge wind resistance[M].Beijing:China Communications Press,2005.
[19] 曹素功.风和列车荷载作用下大跨桥梁动力分析[D].湘潭:湘潭大学,2014. CAO Su-gong.Dynamic analysis of long-span bridge subjected to wind and train[D].Xiangtan:Xiangtan University,2014.
[20] DEN HARTOG J P.Transmission line vibration due to sleet[J].Transactions of the American Institute of Electrical Engineers,1932,51:1074-1077.
[21] 腾二甫,段忠东,张秀华.新月形覆冰导线气动力特性的数值模拟[J].低温建筑技术,2008(1):86-88. TENG Er-fu,DUAN Zhong-dong,ZHANG Xiu-hua.Numerical simulations of aerodynamic characteristics of iced conduct or with crescent shape[J].Low Temperature Architecture Technology,2008(1):86-88.
[22] 曾超.刚桥构件按疲劳寿命服从威布尔分布的可靠度计算[J].西南交通大学学报,1993,28(5):20-23. ZENG Chao.The reliability of fatigue life for steel bridge components by Weibull distribution[J].Journal of Southwest Jiaotong University,1993,28(5):20-23.
[23] IEC.Maritime navigation and radio communication equipment and systerms-shipborne radar-Performance requirements,methods of testing and required test results[R].Geneva:IEC,2007.
[24] 程高,刘永健,张俊光,等.基于Monte Carlo法的多车道公路桥梁车流模拟[J].重庆交通大学学报:自然科学版,2011,30(6):1375-1378. CHENG Gao,LIU Yong-jian,ZHANG Jun-guang,et al.Traffic flow simulation of multi-lane highway bridge based on Monte Carlo method[J].Journal of Chongqing Jiaotong University:Natural Science Edition,2011,30(6):1375-1378.
[25] 张茜,周绪红,狄谨,等.大跨度钢箱梁斜拉桥施工过程风致抖振时域分析及抗风措施[J].长安大学学报:自然科学版,2013,33(1):45-66. ZHANG Qian,ZHOU Xu-hong,DI Jin.Time-domain analysis of wind-induced buffet and win-resistant measures for cable-stayed bridge with steel box girder at construction on stage[J].Journal of Chang’an University:Natural Science Edition,2013,33(1):45-66.