Vol. 11, No. 3, pp. 269-282 (2015)
FATIGUE LIFE EVALUATION OF IN-SERVICE STEEL BRIDGES BY
USING BI-LINEAR S-N CURVES
Chun-sheng Wang 1,*, Ben T. Yen 2, Hai-ting Li 3 and Lan Duan1
1 Engineering Research Center for Large Highway Structure Safety of Ministry of Education, College of Highways, Chang'an University, Xi'an, Shaanxi Province, China
2Department of Civil and Environmental Engineering, Lehigh University, Bethlehem, PA 18015-4729, USA
3Department of Civil Engineering, The University of Hong Kong , Hong Kong, China
*(Corresponding author: E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.)
DOI:10.18057/IJASC.2015.11.3.2
 View Article |
Export Citation: Plain Text | RIS | Endnote |
ABSTRACT
The in-service steel bridges are often required to carry increasing volume of traffic and heavier trucks or freight trains. More attention should be paid to possible fatigue damages of such structures. It has been reported that for many structure details with an equivalent stress range below the constant amplitude fatigue limit (CAFL) and free of fatigue cracks, calculations show that the remaining fatigue life has been exhausted. This condition indicates that it could be too conservative to predict the remaining fatigue life of in-service steel bridges by utilizing the equivalent constant amplitude stress ranges with the direct extension of S-N curves of AASHTO specifications with a slope of -3 to below the CAFL. This over-prediction of fatigue damage may lead to unnecessary rehabilitation and maintenance actions. For a better fatigue life evaluation and prediction, a set of bi-linear S-N curves with a break at the CAFL for the AASHTO fatigue strength categories and with a slope of -4 below, has been proposed for fatigue life evaluation of in-service structures. This paper applies the concept of the equivalent constant amplitude stress range for bi-linear curves to AASHTO specifications and Eurocode. Cases of fatigue evaluation of in-service steel bridge components are studied by correlating the field-measured live-load stresses with the bi-linear S-N curves. Comparative results from the bi-linear S-N curve approach, the current AASHTO specifications and Eurocode approach are presented.
KEYWORDS
Steel bridges, Fatigue life evaluation, Bi-linear S-N curve, Constant amplitude fatigue limit, Equivalent stress range
REFERENCES
[1] AASHTO, “AASHTO LRFD Bridge Design Specifications 5th Ed.”, AASHTO, Washington, DC., USA, 2010.
[2] AASHTO, “AASHTO Manual for Bridge Evaluation”, AASHTO, Washington, DC., USA, 2008.
[3] Yen, B.T., Hodgson, I.C., Zhou, Y. E. and Crudele, B.B., “Estimation of Fatigue Life Below CAFL”, Proceeding of the 2nd International Conference on Fatigue and Fracture in the Infrastructure, ATLSS Engineering Research Center, Lehigh University, Bethlehem, USA, 2009.
[4] Connor, R.J., Hodgson, I.C., Mahmoud, H.N. and Bowman, C.A., “Field Testing and Fatigue Evaluation of the I-79 Neville Island Bridge over the Ohio River”, Center for Advanced Technology for Large Structural Systems (ATLSS), Lehigh University, Bethlehem, USA, 2005.
[5] Crudele, B.B. and Yen, B.T., “Analytical Examination of S-N Curves Below Constant Amplitude Fatigue Limit”, Proceeding of the 1st International Conference on Fatigue and Fracture in the Infrastructure, ATLSS Engineering Research Center, Lehigh University, Bethlehem, PA, USA, 2006.
[6] Kwon, K., Frangopol, D.M. and Soliman, M., “Probabilistic Fatigue Life Estimation of Steel Bridges by Using a Bilinear S-N Approach”, Journal of Bridge Engineering, ASCE, 2012, Vol.17, No.1, pp. 58–70.
[7] Barsom, J.M. and Rolfe, S.T., “Fracture and Fatigue Control in Structures: Applications of Fracture Mechanics, Third Edition”, American Society for Testing and Materials, West Conshohocken, USA, 1999.
[8] Xiang, Y.B., Lu, Z.Z. and Liu, Y.M., “Crack Growth-based Fatigue Life Prediction Using an Equivalent Initial Flaw Model. Part I: Uniaxial Loading”, International Journal of Fatigue. 2010, Vol.32, No.2, pp. 341-349.
[9] Lu, Z.Z., Xiang, Y.B. and Liu, Y.M., “Crack Growth-based Fatigue Life Prediction Using an Equivalent Initial Flaw Model. Part II: Multiaxial Loading”, International Journal of Fatigue. 2010, Vol.32, No.2, pp. 376-381.
[10] Fisher, J.W., Nussbaumer, A., Keating, P.B. and Yen, B.T., “Resistance of Welded Details under Variable Amplitude Long-life Fatigue Loading”, National Cooperative Highway Research Program (NCHRP), Rep. No. 354, Transportation Research Board, National Research Council, Washington, DC., USA, 1993.
[11] Haibach, E., “Modified Linear Damage Accumulation Hypothesis Accounting for a Decreasing Fatigue Strength During Increasing Fatigue Damage”, Laboratorium fur Betriebsfestigkeit, Darmstadt, 1970.
[12] Haibach, E., “Questions Concerning the Fatigue Strength of Welded Joints Considered from a Conventional and a Fracture Mechanical Point of View”, Schw. Schn., 1977, No.4, pp. 140-142.
[13] EN 1993-2, “Eurocode 3: Design of Steel Structures: Part 2: Steel Bridges”, European Committee for Standardization, Brussels, 2006.
[14] Schilling, C.G., Klippstein, K.H., Barsom, J.M., et al., “Fatigue of Welded Steel Bridge Members under Variable Amplitude Loading”, National Cooperative Highway Research Program (NCHRP), Rep. No. 188, Transportation Research Board, National Research Council, Washington, DC., USA, 1978.
[15] Yen, B.T., Hodgson, I.C., Zhou, Y.E. and Crudele, B.B., “Bi-linear S-N Curves and Equivalent Stress Ranges for Fatigue Life Estimation”, Journal of Bridge Engineering, ASCE, 2013, Vol. 18, No.1, pp.26-30.
[16] Wang, C.S. Yan, S.L. and Hao, L., “Fatigue Safety Assessment of Existing Railway Steel Bridges Based on In-situ Monitoring Data”, Proceeding of the 6th International Conference on Maintenance, Safety and Management, Italy, 2012, pp. 812-817.
[17] Partov, D., and Dinev, D., “Structure, Design and Construction of a Steel Orthotropic Bridge in Sofia ”, Advanced Steel Construction, 2007, Vol. 3, No. 4, pp. 752-764.