Fragility analysis of RC bridges considering spatially varying ground motions and SSI

Document Type : Article


Department of Civil Engineering, University of Mohaghegh Ardabili, Ardabil, Iran


Long-span structures like bridges experience different movements at the supports because of the wave-passage, incoherence, and site-response effects. In this study, spatially varying ground motions were used to evaluate the seismic vulnerability of different RC bridges. To gain the goal, three prototypes of Caltrans reinforced concrete curve bridges with different column heights and various radii were selected and used for the numerical study. The spatially correlated ground motions were generated by the conditional simulation method and then converted to corresponding displacements time histories to perform non-uniform excitations. The structures were analyzed under generated series and the fragility curves were developed based on the defined limit states. Furthermore, soil-structure interactions and different soil conditions were included in evaluating the non-linear behavior of the bridges. The results show that the damage exceedance probability increased under non-uniform excitations and it is more obvious for long-span bridges. Also, it is found that the effect of soil-structure interactions on the probability of failure of short-span bridges is negligible but for long-span bridges, the effect is significant. Moreover, it is obvious that for long-span structures situated on soft deposits, a combination of spatially varying ground motions in conjunction with soil-structure inter-actions remarkably increases the responses.


1. Zhong, J., Jeon J.S., Yuan, W., et al. "Impact of spatial variability parameters on seismic fragilities of a cable-stayed bridge subjected to differential support motions", Journal of Bridge Engineering, 22(6) (2017).
2. Zhang, J. and Huo, Y.L. "Evaluating effectiveness and optimum design of isolation devices for highway bridges using the fragility function method", Engineering Structures, 31(8), pp. 1648-1660 (2009).
3. Cornell, C.A., Jalayer, F., Hamburger, R.O., et al. "Probabilistic basis for 2000 SAC Federal Emergency Management Agency steel moment frame guidelines", Journal of Structural Engineering, 128(4), pp. 526-533 (2002).
4. Mackie, K. and Stojadinovic, B. "Probabilistic seismic demand model for California highway bridges", Journal of Structural Engineering, 6(6), pp. 428-481 (2001).
5. Mashayekhi, M.R., Harati, M., Barmchi M., et al. "Introducing a response-based duration metric and its correlation with structural damages", Bulletin of Earthquake Engineering, 17, pp. 5987-6008 (2019).
6. Mashayekhi, M.R., Harati, M., Darzi, A., et al.  Incorporation of strong motion duration in incrementalbased seismic assessments", Engineering Structures, 223, pp. 111-144 (2020).
7. Nielson, B.G. "Analytical fragility curves for highway bridges in moderate seismic zones", Ph.D. Thesis, Georgia Institute of Technology, Atlanta (2005).
8. Ramanathan, K.N. "Next generation seismic fragility curves for California bridges incorporating the evolution in seismic design philosophy", Ph.D. Thesis, Georgia Institute of Technology, Atlanta (2012).
9. Shinozuka, M., Feng, M.Q., Lee, J., et al. "Statistical analysis of fragility curves", Journal of Engineering Mechanics, 126(12), pp. 1224-1231 (2000).
10. Pan, Y., Agrawal, A.K., and Ghosn, M. "Seismic fragility of continuous steel highway bridges in New York state", Journal of Bridge Engineering, 12(6), pp. 689-699 (2007).
11. Padgett, J.E. and DesRoches, R. "Methodology for the development of analytical fragility curves for retrofitted bridges", Earthquake Engineering and Structural Dynamics, 37(8), pp. 1157-1174 (2008).
12. Pourzeynali S. and Hosseinnezahd A. "Reliability analysis of bridge structures for earthquake excitations", Scientia Iranica, 16(1), pp. 1-15 (2009).
13. Basoz, N.I., Kiremidjian, A.S., King, S.A., et al. "Statistical analysis of bridge damage data from the 1994 Northridge, CA, earthquake", Earthquake Spectra, 15(1), pp. 25-54 (1999).
14. De Grandis, S.D., Domaneschi, M., and Perotti, F. "A numerical procedure for computing the fragility of NPP components under random seismic excitation", Nuclear Engineering and Design, 239(11), pp. 2491- 2499 (2009).
15. Perotti, F., Domaneschi, M., and De Grandis, S.D. "The numerical computation of seismic fragility of base-isolated nuclear power plants buildings", Nuclear Engineering and Design, 262, pp. 189-200 (2013).
16. Vasseghi, A., Bahrani, M.K., and Soltani, M. "Seismic retrofit of a typical reinforced concrete bridge bent in Iran", Scientia Iranica, 22(4), pp. 1402-1410 (2015).
17. Hojat Jalali, H. and Maleki, S. "Nonlinear behavior of concrete end diaphragms in straight slab-girder bridges", Scientia Iranica, 22(3), pp. 604-614 (2015).
18. Sotoudeh, M.A., Ghaemian, A., and Sarvghad, Moghadam A. "Determination of limit-states for nearfault seismic fragility assessment of concrete gravity dams", Scientia Iranica, 22(3), pp. 1135-1155 (2019).
19. Ghaffari, E., Estekanchi, H.E., and Vafai, A. "Application of endurance time method in seismic analysis of bridges", Scientia Iranica, 27(4), pp. 1751-1761 (2020).
20. Barnawi, W.T., and Dyke, S.J. "Seismic fragility relationships of a cable-stayed bridge equipped with response modification systems", Journal of Bridge Engineering, 19(8), pp. 1-12 (2014).
21. Mangalathu, S., Choi, E., Park, H.C., et al. "Probabilistic seismic vulnerability assessment of tall horizontally curved concrete bridges in California", Journal of Performance of Constructed Facilities, 32(6), pp. 1-11 (2018).
22. Xie, Y. and DesRoches, R. "Sensitivity of seismic demands and fragility estimates of a typical California highway bridge to uncertainties in its soil-structure interaction modeling", Engineering Structures, 189, pp. 605-617 (2019).
23. Noori, H.R., Memarpour, M.M., and Soltanieh, M.Y. "Effects of ground motion directionality on seismic behavior of skewed bridges considering SSI", Soil Dynamics and Earthquake Engineering, 127, p. 105820 (2019).
24. Chen, X. "System fragility assessment of tall-pier bridges subjected to near-fault ground motions", Journal of Bridge Engineering, 25(3), pp. 1-12 (2020).
25. Shekhar, S., Ghosh, J., and Ghosh, S. "Impact of design code evolution on failure mechanism and seismic fragility of highway bridge piers", Journal of Bridge Engineering, 25(2), pp. 1-19 (2020).
26. Wei, B., Zhuo, Y., Hu, Z., et al. "Influence of site conditions on structural vulnerability of a super high three-tower cable-stayed bridge", Structures, 34, pp. 3882-3893 (2021).
27. Rachedi, M., Matallah, M., and Kotronis, P. "Seismic behavior & risk assessment of an existing bridge considering soil-structure interaction using artificial neural networks", Engineering Structures, 232, p. 111800 (2021).
28. Salimi, M.R., Afsar Dizaj, E., and Kashani, M.M. "Fragility analysis of rectangular and circular reinforced concrete columns under bidirectional multiple excitations", Engineering Structures, 233, p. 111887 (2021).
29. Todorov, B. and Muntasir Billah, A.H.M. "Seismic fragility and damage assessment of reinforced concrete bridge pier under long-duration, near-fault, and far-field ground motions", Structures, 31, pp. 671-685 (2021).
30. Fosoul Saber, A.S. and Tait Michael, J. "Soil-pilestructure interaction effects on seismic demands and fragility estimates of a typical Ontario highway bridge retrofitted with fiber reinforced elastomeric isolator", Soil Dynamics and Earthquake Engineering, 151, p. 106967 (2021).
31. Zanardo, G., Hao, H., and Modena, C. "Seismic response of multi-span simply supported bridges to a spatially varying earthquake ground motion", Earthquake Engineering and Structural Dynamics, 31(6) (2002).
32. Yu, M., Erlei, Y., Bin, R., et al. "Improved Hilbert spectral representation method and its application to seismic analysis of shield tunnel subjected to spatially correlated ground motions", Soil Dynamics and Earthquake Engineering, 111, pp. 119-130 (2018).
33. Papadopoulos, S.P. and Sextos, A.G. "Anti-symmetric mode excitation and seismic response of base-isolated bridges under asynchronous input motion", Soil Dynamics and Earthquake Engineering, 113, pp. 148-161 (2018).
34. Papadopoulos, S.P. and Sextos, A.G. "Simplified design of bridges for multiple-support earthquake excitation", Soil Dynamics and Earthquake Engineering, 113, p. 106013 (2020).
35. Yao, E., Wang, S., Ruan, B., et al. "Numerical study on site response considering ground motion spatial variation", Soil Dynamics and Earthquake Engineering, 127, p. 105836 (2019).
36. Yao, E., Wang, S., Miao, Y., et al. "Simulation of fully non-stationary spatially varying ground motions considering nonlinear soil behavior", Soil Dynamics and Earthquake Engineering, 129, p. 105954 (2020).
37. El Haber, E., Cornou, C., Jongmans, D., et al. "Impact of spatial variability of shear wave velocity on the lagged coherency of synthetic surface ground motions", Soil Dynamics and Earthquake Engineering, 145, p. 106689 (2021).
38. McKenna, F., Scott, M.H., and Fenves, G.L. "Nonlinear finite element analysis software architecture using object composition", Journal of Computing in Civil Engineering, 24(1), pp. 95-107 (2010).
39. Konakli, A. and Der Kiureghian, A., Stochastic Dynamic Analysis of Bridges Subjected to Spatially Varying Ground Motions, Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA (2011).
40. Konakli, K. and Der Kiureghian, A. "Simulation of spatially varying ground motions including incoherence, wave-passage and differential site-response effects", Earthquake Engineering and Structural Dynamics, 41(3), pp. 495-513 (2012).
41. Liao, S. and Zerva, A. "Physically compliant, conditionally simulated spatially variable seismic ground motions for performance-based design", Earthquake Engineering and Structural Dynamics, 35(7), pp. 891- 919 (2006).
42. Der Kiureghian, A. "A coherency model for spatially varying ground motions", Earthquake Engineering and Structural Dynamics, 25(1), pp. 99-111 (1996).
43. Luco, J.E. and Wong, H.L. "Response of a rigid foundation to a spatially random ground motion", Earthquake Engineering and Structural Dynamics, 14(6), pp. 891-908 (1986).
44. Bi, K.M., Hao, H., and Chouw, N. "Influence of ground motion spatial variation, site condition and SSI on the required separation distances of bridge structures to avoid seismic pounding", Earthquake Engineering and Structural Dynamics, 40(9), pp. 1027-1043 (2011).
45. Soyluk, K. and Dumanoglu, A. "Spatial variability effects of ground motions on cable-stayed bridges", Soil Dynamics and Earthquake Engineering, 24(3), pp. 241-250 (2004).
46. Der Kiureghian, A. and Neuenhofer, A. "Response spectrum method for multi-support seismic excitations", Earthquake Engineering and Structural Dynamics, 21(8), pp. 713-740 (1992).
47. Ketchum, M., Chang, V., and Shantz, T., Influence of Design Ground Motion Level on Highway Bridge Costs, Pacific Earthquake Engineering Research Center, University of California Berkeley CA (2004).
48. Taucer, F., Spacone, E., and Filippou, F.C., A Fiber Beam-Column Element for Seismic Response Analysis of Reinforced Concrete Structures, Earthquake Engineering Research Center, College of Engineering, University of California, Berkeley (1991).
49. Mander, J., Priestly, M., and Park, R. "Theoretical stress-strain model for confined concrete", Journal of Structural Engineering, 114(8), pp. 1804-1826 (1988).
50. Zhang, J. and Markis, N. "Seismic response analysis of highway overcrossings including soil-structure interaction", Earthquake Engineering & Structural Dynamics, 31(11), pp. 1967-1991 (2002).
51. Medina, R.A. and Krawinkler, H., Seismic Demands for Non-Deteriorating Frame Structures and Their Dependence on Ground Motions, John, A., Blume, Earthquake Engineering Center, Stanford University, Stanford, CA (2003).
52. Ghobarah, A. "Performance-based design in earthquake engineering: state of development", Engineering Structures, 23(8), pp. 878-884 (2001).
53. Wolf, J. "Spring-dashpot-mass modeling for foundation vibrations", Earthquake Engineering and Structural Dynamics, 26(9), pp. 931-949 (1997).
54. Vamvatiskos, D. and Cornell, C. "Incremental dynamic analysis", Earthquake Engineering and Structural Dynamics, 31(3), pp. 491-514 (2002).