Abstract
Girder unseating in skewed bridges with seat-type abutments has been frequently observed in past earthquakes. This has been attributed to excessive in-plane rotation of the superstructure, and a handful of numerical studies have been conducted to investigate the cause of this rotation. The most common explanation has been pounding between the superstructure and abutment back wall, but this phenomenon has not been verified by experimental testing. Accordingly, this paper describes an experimental investigation into the behavior of skewed bridges, with special attention being given to the interaction between the superstructure and abutment. Shake table experiments are described on a family of four single-span simply supported bridge models with skew angles of 0°, 30°, 45°, and 60° and five different expansion gaps. These models were subjected to a suite of ground motions that varied by type (near field and far field), intensity, and input direction. In total, 876 experiments were conducted. Data collected included superstructure displacements and accelerations, and impact forces at the abutments. The results confirm that a skew bridge experiences large in-plane rotation when the obtuse corner of the span impacts the adjacent back wall with or without slippage along the face of the wall. As a consequence, these bridges can experience large in-plane displacements normal to the back wall at their acute corners, and larger support lengths are required to prevent unseating than for straight bridges. The comprehensive data set obtained in these experiments may be used in future studies to validate numerical models for skew bridges and improve the empirically based minimum support length requirements that are specified for skew bridges in many bridge design codes.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
Acknowledgment is made of the financial support provided by the Federal Highway Administration under Contract No. DTFH61-07-C-00031, and the expert guidance of Dr. Wen-huei (Phillip) Yen (contracting officer's representative), Mr. Fred Faridazar (contracting officer's representative), and Ms. Sheila Duwadi (contracting officer's representative). The authors would like to acknowledge Dr. Patrick Laplace, Chad Lyttle, and Todd Lyttle of the University of Nevada, Reno Earthquake Engineering Laboratory for their advice and dedicated assistance during the shake table experiments.
References
AASHTO. 2011. AASHTO guide specifications for LRFD seismic bridge design. 2nd ed. Washington, DC: AASHTO.
AASHTO. 2012. AASHTO LRFD bridge design specifications. 6th ed. Washington, DC: AASHTO.
Abdel-Mohti, A., and G. Pekcan. 2013a. “Assessment of seismic performance of skew reinforced concrete box girder bridges.” Int. J. Adv. Struct. Eng. 5 (1). https://doi.org/10.1186/2008-6695-5-1.
Abdel-Mohti, A., and G. Pekcan. 2013b. “Effect of skew on the seismic vulnerability of RC box girder highway bridges.” Int. J. Struct. Stab. Dyn. 13 (6): 1350013. https://doi.org/10.1142/S0219455413500132.
Amjadian, M., A. Kalantari, and A. K. Agrawal. 2018. “Analytical study of the coupled motions of decks in skew bridges with the deck–abutment collision.” J. Vib. Control 24 (7): 1300–1321. https://doi.org/10.1177/1077546316659781.
Bjornsson, S. 1997. “Seismic behavior of skew bridges.” Ph.D. thesis, Dept. of Civil and Environmental Engineering, Univ. of Washington.
Buckle, I. G. 1994. The Northridge, California earthquake of January 17, 1994: Performance of highway bridges. Rep. No. NCEER-94-0008. Buffalo, NY: National Center for Earthquake Engineering Research (NCEER).
Buckle, I., M. Hube, G. Chen, W.-H. Yen, and J. Arias. 2012. “Structural performance of bridges in the offshore Maule earthquake of 27 February 2010.” Supplement, Earthquake Spectra 28 (S1): S533–S522. https://doi.org/10.1193/1.4000031.
Caltrans. 2017. Seismic design criteria: Version 2.0 (draft version). Sacramento, CA: Caltrans.
CEN (European Committee for Standardization). 2005. Eurocode 8: Design of structure for earthquake resistance, Part 2—bridges. EN 1998-2. Brussels, Belgium: CEN.
Chen, J., Q. Han, X. Liang, and X. Du. 2017. “Effect of pounding on nonlinear seismic response of skewed highway bridges.” Soil Dyn. Earthquake Eng. 103: 151–165. https://doi.org/10.1016/j.soildyn.2017.09.008.
Chen, L. 2012. Report on highway damage in the Wenchuan earthquake. [In Chinese.] Beijing: China Communications Press.
Deepu, S. P., K. Prajapat, and S. Ray-Chaudhuri. 2014. “Seismic vulnerability of skew bridges under bi-directional ground motions.” Eng. Struct. 71: 150–160. https://doi.org/10.1016/j.engstruct.2014.04.013.
Han, Q., J.-Y. Chen, X.-L. Du, and C. Huang. 2017. “Nonlinear seismic response of skewed highway bridges subjected to bidirectional near-fault ground motions.” J. Bridge Eng. 22 (7): 04017032. https://doi.org/10.1061/(ASCE)BE.1943-5592.0001052.
Huo, Y., and J. Zhang. 2013. “Effects of pounding and skewness on seismic responses of typical multispan highway bridges using the fragility function method.” J. Bridge Eng. 18 (6): 499–515. https://doi.org/10.1061/(ASCE)BE.1943-5592.0000414.
Jennings P. C., G. W. Housner, D. E. Hudson, M. D. Trifunac, G. A. Frazier, J. H. Wood, R. F. Scott, W. D. Iwan, and A. G. Brady. 1971. Engineering features of the San Fernando earthquake of February 9, 1971. Rep. No. EERL 71-02. Pasadena, CA: Earthquake Engineering Research Laboratory.
JRA (Japan Road Association). 2016. “Specifications for highway bridges—Part v seismic design.” Tokyo: JRA.
Kalantari, A., and M. Amjadian. 2010. “An approximate method for dynamic analysis of skewed highway bridges with continuous rigid deck.” Eng. Struct. 32 (9): 2850–2860. https://doi.org/10.1016/j.engstruct.2010.05.004.
Kaviani, P. 2011. “Performance-based seismic assessment of skewed bridges.” Ph.D. thesis, Dept. of Civil and Environmental Engineering, Univ. of California, Irvine.
Kawashima, K., S. Unjoh, J. I. Hoshikuma, and K. Kosa. 2011. “Damage of bridges due to the 2010 Maule, Chile, earthquake.” J. Earthquake Eng. 15 (7): 1036–1068. https://doi.org/10.1080/13632469.2011.575531.
Kun, C., L. Jiang, and N. Chouw. 2017. “Influence of pounding and skew angle on seismic response of bridges.” Eng. Struct. 148: 890–906. https://doi.org/10.1016/j.engstruct.2017.07.024.
Liu, K. Y., K. C. Chang, C. H. Lu, and W. C. Cheng. 2008. “Seismic performance of skew bridge with friction type rubber bearing.” In Proc., 14th World Conf. on Earthquake Engineering. Beijing: China Earthquake Administration.
Maleki, S. 2001. “Free vibration of skewed bridges.” J. Vib. Control 7 (7): 935–952. https://doi.org/10.1177/107754630100700701.
Maleki, S. 2002a. “Deck modeling for seismic analysis of skewed slab-girder bridges.” Eng. Struct. 24 (10): 1315–1326. https://doi.org/10.1016/S0141-0296(02)00066-4.
Maleki, S. 2002b. “Effect of deck and support stiffness on seismic response of slab-girder bridges.” Eng. Struct. 24 (2): 219–226. https://doi.org/10.1016/S0141-0296(01)00084-0.
Maleki, S. 2005. “Seismic modeling of skewed bridges with elastomeric bearings and side retainers.” J. Bridge Eng. 10 (4): 442–449. https://doi.org/10.1061/(ASCE)1084-0702(2005)10:4(442).
Maleki, S., and S. Bagheri. 2014. “Seat width requirement for skewed bridges under seismic loads.” Sci. Iran. Trans. Civ. Eng. 21 (5): 1471–1479.
Maleki, S., and V. Bisadi. 2006. “Orthogonal effects in seismic analysis of skewed bridges.” J. Bridge Eng. 11 (1): 122–130. https://doi.org/10.1061/(ASCE)1084-0702(2006)11:1(122).
Maragakis, E. A. 1985. A model for the rigid body motions of skew bridges. Rep. No. EERL 85-02. Pasadena, CA: Earthquake Engineering Research Laboratory.
Maragakis, E. A., and P. C. Jennings. 1987. “Analytical models for the rigid body motions of skew bridges.” Earthquake Eng. Struct. Dyn. 15 (8): 923–944. https://doi.org/10.1002/eqe.4290150802.
Meng, J. Y., H. Ghasemi, and E. M. Lui. 2004. “Analytical and experimental study of a skew bridge model.” Eng. Struct. 26 (8): 1127–1142. https://doi.org/10.1016/j.engstruct.2004.03.013.
Meng, J. Y., and E. M. Lui. 2000. “Seismic analysis and assessment of a skew highway bridge.” Eng. Struct. 22 (11): 1433–1452. https://doi.org/10.1016/S0141-0296(99)00097-8.
Meng, J.-Y., and E. M. Lui. 2002. “Refined stick model for dynamic analysis of skew highway bridges.” J. Bridge Eng. 7 (3): 184–194. https://doi.org/10.1061/(ASCE)1084-0702(2002)7:3(184).
Meng, J. Y., E. M. Lui, and Y. Liu. 2001. “Dynamic response of skew highway bridges.” J. Earthquake Eng. 5 (2): 205–223. https://doi.org/10.1080/13632460109350392.
Mitchell, D., M. Bruneau, M. Saatcioglu, M. Williams, D. Anderson, and R. Sexsmith. 1995. “Performance of bridges in the 1994 Northridge earthquake.” Can. J. Civ. Eng. 22 (2): 415–427. https://doi.org/10.1139/l95-050.
PEER (Pacific Earthquake Engineering Research Center). 2016. “PEER strong ground motion databases.” Accessed January 9, 2016. http://peer.berkeley.edu/products/strong_ground_motion_db.html.
Rollins, K. M., and S. J. Jessee. 2013. “Passive force-deflection curves for skewed abutments.” J. Bridge Eng. 18 (10): 1086–1094. https://doi.org/10.1061/(ASCE)BE.1943-5592.0000439.
Shamsabadi, A. 2007. “Three-dimensional nonlinear seismic soil-abutment-foundation-structure interaction analysis of skewed bridges.” Ph.D. thesis, Univ. of Southern California.
Shamsabadi, A., and M. Kapuskar. 2006. “Practical nonlinear abutment model for seismic soil-structure interaction analysis.” In Proc., 4th Int. Workshop on Seismic Design and Retrofit of Transportation Facilities. Buffalo, NY: Multidisciplinary Center for Earthquake Engineering Research (MCEER).
Wakefield, R. R., A. S. Nazmy, and D. P. Billington. 1991. “Analysis of seismic failure in skew RC bridge.” J. Struct. Eng. 117 (3): 972–986. https://doi.org/10.1061/(ASCE)0733-9445(1991)117:3(972).
Wu, S. 2019a. “Investigation on the connection forces of shear keys in skewed bridges during earthquakes.” Eng. Struct. 194 (1 September 2019): 334–343. https://doi.org/10.1016/j.engstruct.2019.05.020.
Wu, S. 2019b. “Unseating mechanism of a skew bridge with seat-type abutments and a simplified method for estimating its support length requirement.” Eng. Struct. 191 (15 July 2019): 194–205. https://doi.org/10.1016/j.engstruct.2019.04.059.
Wu, S., I. G. Buckle, and A. Itani. 2016. Effect of skew on seismic performance of bridges with seat-type abutments. Rep. No. CCEER-16-08. Reno, NV: Center for Civil Engineering Earthquake Research, Dept. of Civil and Environmental Engineering, Univ. of Nevada.
Wu, S., I. G. Buckle, A. Itani, and D. Istrati. 2019. “Experimental datasets from large-scale shake table experiments on skew bridges.” Accessed January 14, 2019 https://doi.org/10.17605/OSF.IO/2Q3DP.
Zakeri, B., and G. G. Ghodrati Amiri. 2014. “Probabilistic performance assessment of retrofitted skewed multi span continuous concrete I-girder bridges.” J. Earthquake Eng. 18 (6): 945–963. https://doi.org/10.1080/13632469.2014.916241.
Information & Authors
Information
Published In
Journal of Bridge Engineering
Volume 24 • Issue 10 • October 2019
Copyright
© 2019 American Society of Civil Engineers.
History
Received: Jul 28, 2018
Accepted: May 8, 2019
Published online: Aug 14, 2019
Published in print: Oct 1, 2019
Discussion open until: Jan 14, 2020
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.