为了解决大跨度桥梁在随机车辆荷载和风荷载作用下局部应力求解耗时问题，首先以矮寨大桥为工程背景，建立壳-梁混合单元有限元模型，确定大桥应力的关键位置及关键点，采用分段拟合方法获得随机车辆荷载的影响面函数和风荷载的影响线函数；结合吉茶高速实际交通量特征及随机参数分布特征，采用蒙特卡罗方法，编制抽样程序生成随机车流样本。其次采用风-车-桥耦合振动分析获得典型车辆的等效车辆荷载；引入风荷载动力影响系数，提出了一种简便实用的随机车流下大跨度桥梁风致应力分析方法。最后应用ANSYS计算分析结果验证所提方法的正确可行性，分析矮寨大桥在随机车流和风荷载联合作用下的关键点应力响应。结果表明：风速低于15 m·s-1时，风荷载引起大桥关键点应力响应远小于车辆荷载引起的应力响应；繁忙车流下应力响应的幅值并不比稀疏车流下的应力幅值大很多，但是繁忙车流下应力响应的峰值数量远大于稀疏车流下的峰值数量，即应力的循环次数多，会增大桥梁的疲劳损伤。
Abstract
To solve the time-consuming problem of the local stress analysis of a long-span bridge under the combined action of random traffic and wind loads, the Aizhai Bridge was selected as an example in this paper and a finite element model with shell elements and beam elements for the bridge was established using ANSYS software. The critical locations of the bridge were then determined by refined analyses and the stress influence functions used for calculating the dynamic stress response of the bridge under random traffic and wind loads were calculated by segmented polynomial fitting using the Curve Fitting Toolbox in MATLAB. Based on the characteristics of actual traffic volume and distribution characteristics of random parameters of the bridge, the random traffic flow simulation program was compiled by adopting the Monte-Carlo simulation method and MATLAB software, and random traffic samples were then simulated. The moving equivalent dynamic vehicle loadings were calculated based on full interaction analyses of a single-vehicle-bridge-wind system. By introducing dynamic influence coefficients for wind loads, this paper presented an efficient approach for dynamic stress analysis of a long-span bridge under the combined action of random traffic and wind loads based on the stress influence function. The correctness of the proposed method was verified by comparison with the results of ANSYS analysis. Finally, the local stress responses of the key members of the bridge under the combined action of random vehicle and wind loads were analyzed. The results show that the wind-induced stress response is much lower than that induced by random traffic load when wind speed is less than 15 m·s-1. The maximum stress amplitude induced by busy traffic flow is not greater than that induced by free traffic flow. However, there are more peak values in the response for busy traffic flow than those for free traffic flow, which will affect the gross number of stress cycles and increase the fatigue damage to the bridge.
关键词
桥梁工程 /
应力响应 /
影响函数 /
大跨度悬索桥 /
随机车流 /
等效车辆荷载
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Key words
bridge engineering /
stress response /
influence function /
long-span suspension bridge /
random traffic /
equivalent dynamic vehicle load
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中图分类号：
U441
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参考文献
[1] LEROSE C. The Collapse of the Silver Bridge[J/OL]. West Virginia Historical Society Quarterly, 2001, 15(4):3.[2010-11-17]. http://www.wvculture.org/history/wvhs1504.html.
[2] National Transportation Safety Board. Highway Accident Report:Collapse of Ⅰ-35W Highway Bridge Minneapolis, Minnesota, August 1, 2007, NTSB/HAR-08/03[R]. Washington DC:National Transportation Safety Board, 2008.
[3] XU Y L, GUO W H. Dynamic Analysis of Coupled Road Vehicle and Cable-stayed Bridge System Under Turbulent Wind[J]. Engineering Structures, 2003, 25:473-486.
[4] CAI C S, CHEN S R. Framework of Vehicle-bridge-wind Dynamic Analysis[J]. Journal of Wind Engineering and Industrial Aerodynamics, 2004, 92:579-607.
[5] CHEN S R, WU J. Dynamic Performance Simulation of Long-span Bridge Under Combined Loads of Stochastic Traffic and Wind[J]. Journal of Bridge Engineering, 2010, 15(3):219-230.
[6] XIA H, GUO W W, ZHANG N, et al. Dynamic Analysis of a Train-bridge System Under Wind Action[J]. Computers and Structures, 2008, 86:1845-1855.
[7] 李永乐.风-车-桥系统非线性空间耦合振动研究[D].成都:西南交通大学,2003. LI Yong-le. Nonlinear Three-dimensional Coupling Vibration of Wind-vehicle-bridge System[D]. Chengdu:Southwest Jiaotong University, 2003.
[8] 韩万水,陈艾荣.风-汽车-桥梁系统空间耦合振动研究[J].土木工程学报,2007,40(9):53-58. HAN Wan-shui, CHEN Ai-rong. Three-dimensional Coupling Vibration of Wind-vehicle-bridge Systems[J]. China Civil Engineering Journal, 2007, 40(9):53-58.
[9] 韩艳,陈浩,沈炼,等.气动力参数对风-车-桥系统耦合动力响应的影响[J].中国公路学报,2015,28(9):57-66,126. HAN Yan, CHEN Hao, SHEN Lian, et al. Effects of Aerodynamic Parameters on Coupled Dynamic Responses of Wind-vehicle-bridge System[J]. China Joural of Highway and Transport, 2015, 28(9):57-66, 126.
[10] CHEN S R, WU J. Modeling Stochastic Live Load for Long-span Bridge Based on Microscopic Traffic Flow Simulation[J]. Computers and Structures, 2011, 89:813-824.
[11] WANG T, HAN W S, YANG F, et al. Wind-vehicle-bridge Coupled Vibration Analysis Based on Random Traffic Flow Simulation[J]. Journal of Traffic and Transportation Engineering:English Edition, 2014, 1(4):293-308.
[12] YIN X F, LIU Y, GUO S H, et al. Three-dimensional Vibrations of a Suspension Bridge Under Stochastic Traffic Flows and Road Roughness[J]. International Journal of Structural Stability and Dynamics, 2016, 16(7): 1550038.
[13] 宗周红,李峰峰,夏叶飞,等.基于WIM的新沂河大桥车辆荷载模型研究[J].桥梁建设,2013,43(5):29-36. ZONG Zhou-hong, LI Feng-feng, XIA Ye-fei, et al. Study of Vehicle Load Models for Xinyi River Bridge Based on VIM Data[J]. Bridge Construction, 2013, 43(5): 29-36.
[14] 谢静思.吉茶高速公路矮寨大桥车辆荷载谱研究[D].长沙:长沙理工大学,2014. XIE Jing-si. Research on Load Spectrum in Aizhai Bridge of Jicha Highway[D]. Changsha: Changsha University of Science & Technology, 2014.
[15] HAN Y, CAI C S, ZHANG J R, et al. Effect of Aerodynamic Parameters on the Dynamic Responses of Road Vehicles and Bridges Under Cross Winds[J]. Journal of Wind Engineering and Industrial Aerodynamics, 2014, 134: 78-95.
[16] CHEN S R, CAI C S. Equivalent Wheel Load Approach for Slender Cable-stayed Bridge Fatigue Assessment Under Traffic and Wind: Feasibility Study[J]. Journal of Bridge Engineering, 2007, 12(6): 755-764.
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脚注
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基金
国家重点基础研究计划（“九七三”计划）项目（2015CB057706）； 国家自然科学基金项目（51678079，51778073，51628802）
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