Investigating Importance of Friction between Elastomer Bearing and Its Support on the Seismic Performance of Skew Seat-type Bridges

Document Type : Research


1 Ph.D. Candidate, Department of Civil Engineering, Urmia University, Urmia Iran.

2 Professor, Department of Civil Engineering, Urmia University, Urmia Iran.


Seat-type bridges compose a large portion of bridge inventories in different countries. There is evidence of excellent performance of these bridges in Iran during past earthquakes, that could be attributed to the slip of elastomeric bearings. This study investigates how the coefficient of friction between elastomeric bearing and its support and skew angle of the bridge could affect the performance of seat-type bridges. This assessment is done using incremental dynamic analyses on a three-span model bridge. The finite element model accounts for the slip of bearings, backfill passive resistance, and plastic deformation of columns. The results show that while the skew angle predominantly affects the required seat width in different codes, the correlation between the required seat width and coefficient of friction is much stronger. It is also established that, considering the mean response, there is no possibility of unseating even for maximum considered level ground motion. At the same time, the possibility of a loss of access due to abutment displacement is quite probable even for a design-basis earthquake. Furthermore, it is shown that the slip of the bearings significantly reduces seismic demand on the substructure. The findings show the paramount importance of modeling bearing slip in any seismic assessment of these bridge types


1. Moinfar, A.A., A. Naderzadeh, A., (1990), An immediate and preliminary report on the Manjil, Iran earthquake of 20 june 1990, Bulletin of New Zealand Society of Earthquake Engineering, 23(4) 254-283. [DOI:10.5459/bnzsee.23.4.254-283]
2. Eshghi, S., Ahari, M.N., (2005), Performance of transportation systems in the 2003 Bam, Iran, earthquake, Earthquake Spectra, 21(1) 455-468. [DOI:10.1193/1.2098891]
3. Yashinsky, M., Oviedo, R., Ashford, S., Fargier‐Gabaldon, L., Hube, M., (2010), Performance of Highway and Railway Structures during the February 27, 2010 Maule Chile Earthquake, EERI/PEER/FHWA Report.
4. Kawashima K., Unjoh S., Hoshikuma J.I., Kosa, K., (2011), Damage of bridges due to the 2010 Maule Chile Earthquake, Journal of Earthquake Engineering, 15(7) 1036-68. [DOI:10.1080/13632469.2011.575531]
5. Meng, J.Y., Lui, E.M., (2000), Seismic analysis and assessment of a skew highway bridge, Engineering Structures, 22(12) 1433-1452. [DOI:10.1016/S0141-0296(99)00097-8]
6. Kaviani, P., Zareian, F., Taciroglu, E., (2012), Seismic behavior of reinforced concrete bridges with skew-angled seat-type abutments, Engineering Structures, 45(1) 137-150. [DOI:10.1016/j.engstruct.2012.06.013]
7. Ghotbi, A.R., (2014), Performance-based seismic assessment of skewed bridges with and without considering soil-foundation interaction effects for various site classes, Earthquake Engineering and Engineering Vibration, 13(4) 357-373. [DOI:10.1007/s11803-014-0248-7]
8. Omrani, R., Mobasher, B., Sheikhakbari, S., Zareian, F., Taciroglu, E., (2017), Variability in the predicted seismic performance of a typical seat-type California bridge due to epistemic uncertainties in its abutment backfill and shear-key models, Engineering Structures, 148(5) 718-738 [DOI:10.1016/j.engstruct.2017.07.018]
9. Wu, S., (2019), Investigation on the connection forces of shear keys in skewed bridges during earthquakes, Engineering Structures, 194 (3) 334-343. [DOI:10.1016/j.engstruct.2019.05.020]
10. Filipov E.T., Revell J.R., Fahnestock L.A., LaFave J.M., Hajjar J.F., Foutch D.A., Steelman J.S., (2013), Seismic performance of highway bridges with fusing bearing components for quasi-isolation, Earthquake Engineering and Structural Dynamics, 42(12) 1375-1394. [DOI:10.1002/eqe.2277]
11. Kelly, J.M., Konstantinidis, D., (2009), Effect of friction on unbonded elastomeric bearings, ASCE Journal of Engineering Mechanics, 135(9) 953-960. [DOI:10.1061/(ASCE)EM.1943-7889.0000019]
12. Konstantinidis, D., Kelly, J.M., Makris, N., (2008), Experimental investigations on the seismic response of bridge bearings, EERC 2008-02, Earthquake Engineering Research Center.
13. IDOT, (2012), Bridge manual, Illinois Department of Transportation, Bureau of Bridges and Structures, Division of Highways.
14. AASHTO, (2017), AASHTO LRFD Bridge Design Specifications_SI Unit 2008. Washington, D.C.: American Association of State Highway and Transportation Officials.
15. Wang, K.H., Li, C., Li, Q., Li, Y., (2014), Seismic design method of small and medium span bridge considering bearing friction slipping," Gongcheng Lixue/Engineering Mech., 31(6) 85-92.
16. Buckle, I.G., Friedland, I., Mander, J.B., Martin, G., Nutt, R., Power, M., (2006), Seismic Retrofitting Manual for Highway Structures : Part 1 - Bridges, pp. 658.
17. McKenna, F., Fenves, G. L, and Scott, M. H. (2000) Open System for Earthquake Engineering Simulation. University of California, Berkeley,
18. JMander, J.B., Priestley, M.J.N, Park, R., (1988), Theoretical Stress‐Strain Model for Confined Concrete, Journal of Structural Engineering, 114(8) 854-875. [DOI:10.1061/(ASCE)0733-9445(1988)114:8(1804)]
19. Caltrans, (2019), Seismic Design Criteria Version 2.0, Calif. Dep. Transp. Sacramento, CA, U.S.
20. Billah, A. M., Alam, M.S. (2014), Seismic performance evaluation of multi-column bridge bents retrofitted with different alternatives using incremental dynamic analysis. Engineering Structures, 62(5) 105-117. [DOI:10.1016/j.engstruct.2014.01.005]