The Response of a Highly Skewed Steel I-Girder Bridge with Different Cross-Frame Connections


  • Y. Almoosi Department of Civil Engineering, College of Engineering, University of Baghdad, Iraq
  • N. Oukaili Department of Civil Engineering, College of Engineering, University of Baghdad, Iraq
Volume: 11 | Issue: 4 | Pages: 7349-7357 | August 2021 |


Braces in straight bridge systems improve the lateral-torsional buckling resistance of the girders by reducing the unbraced length, while in horizontally curved and skew bridges, the braces are primary structural elements for controlling deformations by engaging adjacent girders to act as a system to resist the potentially large forces and torques caused by the curved or skewed geometry of the bridge. The cross-frames are usually designed as torsional braces, which increase the overall strength and stiffness of the individual girders by creating a girder system that translates and rotates as a unit along the bracing lines. However, when they transmit the truck’s live load forces, they can produce fatigue cracks at their connections to the girders. This paper investigates the effect of using different details of cross-frames to girder connections and their impacts on girder stresses and twists. Field testing data of skewed steel girders bridge under various load passes of a weighed load vehicle incorporated with a validated 3D full-scale finite element model are presented in this study. Two types of connections are investigated, bent plate and pipe stiffener. The two connection responses are then compared to determine their impact on controlling the twist of girder cross-sections adjacent to cross-frames and also to mitigate the stresses induced due to live loads. The results show that the use of a pipe stiffener can reduce the twist of the girder’s cross-section adjacent to the cross-frames up to 22% in some locations. In terms of stress ranges, the pipe stiffener tends to reduce the stress range by 6% and 4% for the cross-frames located in the abutment and pier skew support regions respectively.


skew bridge, field test, cross-frames, bent plates, pipe stiffener, fatigue


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D. W. White et al., "Guidelines for Analysis Methods and Construction Engineering of Curved and Skewed Steel Girder Bridges," Transportation Research Board, NCHRP Report 725, 2012. Accessed: Jun. 14, 2021. [Online]. Available:

T. A. Helwig and J. Yura, "Steel Bridge Design Handbook: Bracing System Design," Federal Highway Administration, Office of Bridge Technology, USA, FHWA-IF-12-052, 2012.

AASHTO LRFD - Bridge Design Specifications, 8th ed. Washington DC, USA: LRFD, 2017.

Guidelines for Steel Girder Bridge Analysis, 3rd ed. Washington DC, USA: AASHTO/NSBA, 2019.

C. Quadrato et al., "Cross-Frame Connection Details for Skewed Steel Bridges," Center for Transportation Research, The University of Texas at Austin, Austin, TX, USA, FHWA/TX-11/0-5701-1, 2010.

A. Battistini, W. Wang, T. Helwig, M. Engelhardt, and K. Frank, "Stiffness Behavior of Cross Frames in Steel Bridge Systems," Journal of Bridge Engineering, vol. 21, no. 6, Feb. 2016, Art. no. 04016024.

M. D. Bowman, G. Fu, Y. E. Zhou, R. J. Connor, and A. A. Godbole, "Fatigue Evaluation of Steel Bridges," NCHRP Report 721, 2012.

J. McConnell, M. Chajes, and K. Michaud, "Field Testing of a Decommissioned Skewed Steel I–Girder Bridge: Analysis of System Effects," Journal of Structural Engineering, vol. 141, no. 1, Jan. 2015, Art. no. D4014010.

R. Haghani, M. Al-Emrani, and M. Heshmati, "Fatigue-Prone Details in Steel Bridges," Buildings, vol. 2, no. 4, pp. 456–476, Dec. 2012.

A. S. (Grider) Barth and M. D. Bowman, "Fatigue Behavior of Welded Diaphragm-to-Beam Connections," Journal of Structural Engineering, vol. 127, no. 10, pp. 1145–1152, Oct. 2001.

J. M. Stallings, T. E. Cousins, and J. W. Tedesco, "Fatigue of Diaphragm-Girder Connections," Transportation Research Record, vol. 1594, no. 1, pp. 34–41, Jan. 1997.

M. Ojalvo and R. S. Chambers, "Effect of Warping Restraints on I-Beam Buckling," Journal of the Structural Division, vol. 102, no. ST12, pp. 2351–2360, Dec. 1977.

J. Zhou, C. Bennett, A. Matamoros, and J. Li, "Skewed Steel Bridges, Part II: Cross-Frame and Connection Design to Ensure Brace Effectiveness," University of Kansas Center for Research, Inc., Lawrence, KS, USA, SM Report 118, Mar. 2017.

"BDI strain transducer ST-350 specifications sheet." BDI, 2006.

J. R. McConnell, M. Radovic, and K. Ambrose, "Field Evaluation of Cross-Frame and Girder Live-Load Response in Skewed Steel I-Girder Bridges," Journal of Bridge Engineering, vol. 21, no. 3, p. 04015062, Mar. 2016.

Y. Almoosi, J. McConnell, and N. Oukaili, "Structural Modeling of Cross-Frame Behavior in Steel Girder Bridges," in 2019 12th International Conference on Developments in eSystems Engineering (DeSE), Kazan, Russia, Oct. 2019, pp. 620–625.

ABAQUS 6.14: Abaqus/CAE User’s Guide. Waltham, MA, USA: Simulia, 2019.

Y. Almoosi, J. McConnell, and N. Oukaili, "Evaluation of the Variation in Dynamic Load Factor Throughout a Highly Skewed Steel I-Girder Bridge," Engineering, Technology & Applied Science Research, vol. 11, no. 3, pp. 7079–7087, Jun. 2021.


How to Cite

Y. Almoosi and N. Oukaili, “The Response of a Highly Skewed Steel I-Girder Bridge with Different Cross-Frame Connections”, Eng. Technol. Appl. Sci. Res., vol. 11, no. 4, pp. 7349–7357, Aug. 2021.


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