Fatigue Life Prediction on Rib-to-Deck Welded Joints of Steel Bridge Deck Based on LEFM
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摘要: 为研究反复荷载作用下正交异性钢桥面中U型肋与桥面板焊接接头的疲劳性能,基于断裂力学基本理论,利用有限元方法,进行了肋-板接头的疲劳寿命评估.根据正交异性钢桥面与U型肋连接构造基本形式,利用有限元软件ANSYS建立了包含3个U型肋的正交异性钢桥面平面有限元模型;考虑肋-板连接位置处焊接细节的4种典型裂纹,计算了2个加载工况下各裂纹处等效应力强度因子,并分析了初始裂纹长度、桥面板厚度、U型肋高度和U型肋厚度对等效应力强度因子的影响规律;依据Eurocode 3规范中正交异性钢桥面肋-板接头加载模式,采用桥面板与U型肋连接构造二维有限元模型,计算得到典型裂纹的等效应力强度因子,建立了基于断裂力学疲劳扩展模型为基础的正交异性钢桥面肋-板接头的疲劳寿命预测方法.研究结果表明:基于线弹性断裂力学原理计算得到的疲劳寿命均大于Eurocode 3规范计算值,桥面板厚度选用16~18 mm及将初始裂纹长度控制在0.1 mm以下可有效地提高板-肋接头疲劳寿命.Abstract: In order to explore the fatigue performance of U-shaped rib-to-deck welded joints of orthotropic steel bridge deck under cyclic loading, based on linear elastic fracture mechanics (LEFM), fatigue life evaluation was carried out using finite element method (FEM). According to the structure features of rib-to-deck welded joints of orthotropic steel bridge deck, 2D FEM model with 3 U-shaped ribs was built using ANSYS software. Presetting 4 kinds of initial cracks for weld detail, the equivalent stress intensity factors (ESIF) at each crack with 2 loading cases were calculated. The relationship between stress intensity factor and influential parameters, including initial cracks length, thickness of deck plate, height and thickness of U-shaped rib, was analyzed. In accordance with weld detail category of orthotropic steel bridge deck in Eurocode 3, ESIF at every crack were obtained, and fatigue life prediction method of weld joint of orthotropic steel deck were proposed based on fatigue crack propagation model in LEFM theory. Results show that fatigue life calculated with LEFM is greater than the value in Eurocode 3, and fatigue life of the welded joint will be enhanced when the deck plate thickness is 16-18 mm and initial crack length is less than 0.1 mm.
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Key words:
- orthotropic steel deck /
- weld detail /
- fatigue life /
- LEFM /
- SIF
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TSAKOPOULOS P A, FISHER J W. Full-scale fatigue tests of steel orthotropic decks for the Williamsburg Bridge[J]. Journal of Bridge Engineering, 2003, 8(5):323-333. CONNOR R J, FISHER J W. Consistent approach to calculating stresses for fatigue design of welded rib-to-web connections in steel orthotropic bridge decks[J]. Journal of Bridge Engineering, 2006, 11(5):517-525. MIKI C. Fatigue damage in orthotropic steel bridge decks and retrofit works[J]. Int. J. Steel Struct, 2006, 6(4):255-267. WOLCHUK R. Lessons from weld cracks in orthotropic decks on three European bridges[J]. J. Structural Engineering, ASCE, 1990, 116(1):75-84. British Standards Institution. BS5400 Steel, concrete and composite bridges, part 10, code of practice for fatigue[S]. London:BSI, 1980. European Committee Standardization. EN 1993-1-9 Eurocode 3 design of steel structures, part 1-9:fatigue strength of steel structures[S]. Brussels:CEN, 2005. American Association of State Highway and Transportation Officials. LRFDUS-7 LRFD bridge design specifications[S]. 7th Edition. Washington D C:AASHTO, 2015. 童乐为,沈祖炎. 正交异性钢桥面疲劳验算[J]. 土木工程学报,2000,33(3):16-21. TONG Lewei, SHEN Zuyan. Fatigue assessment of orthotropic steel bridge decks[J]. China Civil Engineering Journal, 2000, 33(3):16-21. 蒲黔辉,高立强,刘振标,等. 基于热点应力法的正交异性钢桥面疲劳验算[J]. 西南交通大学学报,2013,48(3):395-401. PU Qianhui, GAO Liqiang, LIU Zhenbiao, et al. Fatigue assessment of orthotropic steel bridge deck based on hot spot stress method[J]. Journal of Southwest Jiaotong University, 2013, 48(3):395-401. 卫星,邹修兴,姜苏,等.正交异性钢桥面肋-板焊接残余应力的数值模拟[J].桥梁建设,2013,44(4):27-33. WEI Xing, ZOU Xiuxing, JIANG Su, et al. Numerical simulation on residual stresses in rib-to-deck welded joints of orthotropic steel bridge deck[J]. Bridge Construction, 2013, 44(4):27-33. LIU R, LIU Y, JI B, et al. Hot spot stress analysis on rib-deck welded joint in orthotropic steel decks[J]. Journal of Constructional Steel Research, 2014, 97:1-9. 姜苏. 基于断裂力学的正交异性钢桥面与纵肋焊接细节疲劳寿命评估[D]. 成都:西南交通大学,2014. International Institute of Welding. ⅡW-2259-15 Recommendations for fatigue design of welded joints and components[S]. Switzerland:Springer International Publishing, 2016. 日本鋼構造協会. JSS Ⅳ-092010鋼構造物の疲労設計指針[S]. 東京:技報堂出版,2012. British Standards Institution. BS 7608 Fatigue design and assessment of steel structures:code of practice[S]. London:BSI, 1993. British Standards Institution. BS 7910 Guide to methods for assessing the acceptability of flaws in metallic structures[S]. London:BSI, 2005.
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