Probabilistic Seismic Demand Assessment of Steel Moment Resisting Frames Isolated by LRB

Document Type : Research

Authors

1 Associate Professor, K. N. Toosi University of Technology, Civil Engineering Department, Tehran, Iran,

2 Graduated Student in Earthquake Engineering, Department of Civil Engineering, Isfahan (khorasgan) Branch, Islamic Azad University, Isfahan, Iran

3 Ph.D of Structural Engineering, Faculty of Engineering, University of Guilan, Rasht, Iran,

Abstract

Seismic isolation is an effective approach used in controlling the seismic responses and retrofitting of structures. The construction and installation of such systems are expanded nowadays due to modern improvements in technology. In this research, the seismic performance of steel moment resisting frames isolated by Lead Rubber Bearing (LRB) is assessed, and the seismic demand hazard curves of the frames are developed using Probabilistic Seismic Demand Analysis (PSDA). In addition, the effects of LRB on overstrength, ductility and response modification factor of the frames are studied. To achieve this, Incremental Dynamic Analyses (IDA) are conducted using 10 records of near field earthquake ground motions on the intermediate steel moment resisting fixed base frames with 3, 6 and 9 storeys retrofitted by LRB according to ASCE 41. The results show that in the case of isolated frames, the values of ductility and response modification factor are decreased in comparison with those of fixed base frames. Moreover, based on the developed fragility curves, seismic isolation is more effective in improving structural performance in extensive and complete damage states compared to slight and moderate damage states. However, increasing the height of both structural groups (i.e. fixed base and base isolated) results in reduction in performance level. Besides, the probability of occurrence of a certain demand is reduced by base isolation.

Keywords


1. American institute of steel construction, "AISC-360-Specification for structural steel buildings", Chicago, Illinois, 2010.
2. American Society of Civil Engineers, "ASCE/SEI7-Minimum design loads for buildings and other structures", Reston, Virginia, 2010.
3. American Society of Civil Engineers, "ASCE-41-Seismic evaluation and retrofit of existing buildings", Federal Emergency Management Agency, 2013.
4. Aslani, H., "Probabilistic Earthquake Loss Estimation and Loss Disaggregation in Buildings", PhD Thesis, Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, 2005.
5. BHRC, Iranian code of practice for seismic resistance design of buildings, standard No. 2800-5, 3rd edition. Building and Housing Research Center. Tehran, 2005.
6. Cordova, P.P., Deierlein, G.G., Mehanny, S.S.F., Cornell, C.A., "Development of two-parameter seismic intensity measure and probabilistic assessment procedure",Proceedings of the 2nd U.S. - Japan Workshop on Performance-based Earthquake Engineering Methodology for Reinforced Concrete Building Structures, Sapporo, Japan, 2001, p. 187-206.
7. Cornell, C.A., "Calculating building seismic performance reliability", Eleventh Conference on Earthquake Engineering, Acapulco, Mexico, 1996.
8. Dezfuli, F. H., Li, Sh., Alam, M. S., Wang, J. "Effect of constitutive models on the seismic response of an SMA-LRB
9. isolated highway bridge", Engineering Structures. 2017, 148: 113-125. [DOI:10.1016/j.engstruct.2017.06.036]
10. Fanaie, N., Ezzatshoar, S., "Studying the seismic behavior of gate braced frames by incremental dynamic analysis (IDA)", Constructional and steel research, vol.99, 2014, p. 111-120. [DOI:10.1016/j.jcsr.2014.04.008]
11. Han, R., Li, Y., van de Lindt, J.,"Seismic risk of base isolated non-ductile reinforced concrete buildings considering uncertainties and mainshock-aftershock sequences",Structural Safety, vol.50, 2014, p. 39-56. [DOI:10.1016/j.strusafe.2014.03.010]
12. HAZUS_MH MR4, Earthquake Model Technical Manual. Federal Emergency Management Agency. Washington, DC, 2009.
13. Hutchinson, T.C., Chai, Y.H., Boulanger, R.W., Idriss, I.M., "Inelastic seismic response of extended pile-shaft-supported bridge structures", Earthquake Spectra, vol.20 (4), 2004, p. 1057-1080. [DOI:10.1193/1.1811614]
14. Jalali, S.A., Banazadeha, M., Abolmaali, A., Tafakori, E., "Probabilistic seismic demand assessment of steel moment frames with side-plate connections", Scientia Iranica, vol.19 (1), 2012, 27-40. [DOI:10.1016/j.scient.2011.11.036]
15. Karim, K.R., Yamazaki, F., "Effect of isolation on fragility curves of highway bridges based on simplified approach", Soil Dynamics and Earthquake Engineering, vol.27 (5), 2007, p. 414-426. [DOI:10.1016/j.soildyn.2006.10.006]
16. Khaloo, A.R., Tonekaboni, M. "Risk based seismic assessment of structures", Advances in Structural Engineering, 16(2), 2013, p. 307-314. [DOI:10.1260/1369-4332.16.2.307]
17. Luco, N., Cornell, C.A., "Structure-specific scalar intensity measures for near-source and ordinary earthquake ground motions", Earthquake Spectra, vol. 23(3), 2007, p. 357-392. [DOI:10.1193/1.2723158]
18. Luco, N., Mai, P.M., Cornell, C.A., Beroza, G. C., "Probabilistic seismic demand analysis at a near fault site using ground motion simulations based on a stochastic kinematic earthquake source model",Proceedings of the 7th U.S. National Conference on Earthquake Engineering, Boston, Massachusetts 2002.
19. Massumi, A., Tasnimi, A.A., Saatcioglu, M., "Prediction of seismic overstrength in concrete moment resisting frames using incremental static and dynamic analysis", Proceedings of the 13th World Conference on Earthquake Engineering, Vancouver, B.C, Canada,2004.
20. Mazzoni, S., McKenna, F., Scott, M.H., Fenves, G.L., Jeremic, B., "OpenSees Command Language Manual", Berkely, CA: Pacific Earthquake Engineering Center, Univ, California at Berkely, 2007.
21. Mwafy, A.M., Elnashai, A.S., "Calibration of force reduction factors of RC buildings", Journal of Earthquake Engineering, vol. 6(2), 2002: 239-73. [DOI:10.1080/13632460209350416]
22. Naeim, F., Kelly, J.M., "Design of Seismic Isolated Structures from Theory to Practic", (6th edition), John Wiley & Sons, Inc, New York, USA, 1999. [DOI:10.1002/9780470172742]
23. Sewell, R.T., Toro, G.R., McGuire, R.K., "Impact of Ground Motion Characterization on Conservatism and Variability in Seismic Risk Estimates", Report NUREG/CR-6467, U.S. Nuclear Regulatory Commission, Washington, D.C, 1991.
24. Nakhostin Faal, H., Poursha, M. "Applicability of the N2, extended N2 and modal pushover analysis methods for the seismic evaluation of base-isolated building frames with lead rubber bearings (LRBs).", Soil Dynamics and Earthquake Engineeirng, 2017, 98: 84-100 [DOI:10.1016/j.soildyn.2017.03.036]
25. Shome, N., Cornell, C.A., Bazzurro, P., Eduardo, C.J., "Earthquakes, records and nonlinear responses", Earthquake Spectra, vol.14 (3), 1998: 469-500. [DOI:10.1193/1.1586011]
26. Shome, N., Cornell, C.A. "Probabilistic Seismic Demand Analysis of Nonlinear Structures", RMS Report-35, Reliability of Marine Structures Group, Stanford University, Stanford, 1999.
27. Stewart, J.P., Chiou, S.J., Bray, J.D., Garves, R.W., Somerville, P.G., Abrahamson, N.A., "Ground motion evaluation procedures for performance based design", Soil Dynamics and Earthquake Engineering, vol.22, 2002, p.765-772. [DOI:10.1016/S0267-7261(02)00097-0]
28. Tena-Colunga, A., Gómez-Soberón, L.A., "Torsional response of base-isolated structures due to asymmetries in the superstructure", Engineering Structure, vol.24 (12), 2002, p. 1587-1599. [DOI:10.1016/S0141-0296(02)00102-5]
29. Tyler, R.G., Robinson, W.H., " High-Strain tests on lead-rubber bearing for earthquake loadings", Bull new Zealand Natl. Soc, Earthquake Engineering, vol.7(2), 1984, p. 90-105.
30. Ryan, K.L., Kelly, J.M., Chopra, A.K., "Nonlinear model for lead-rubber bearings including axial-load effects", Journal of Engineering Mechanics, vol. 131(12), 2005: 1270-8. [DOI:10.1061/(ASCE)0733-9399(2005)131:12(1270)]
31. Uang, C.M., "Establishing R or (Rw) and Cd factor building seismic provision", Structural Engineering, vol. 117(1), 1991, p. 19-28. [DOI:10.1061/(ASCE)0733-9445(1991)117:1(19)]
32. Wen, Y.K., Ellingwood, B.R., "The role of fragility assessment in consequence-based engineering", Earthquake Spectra, vol. 21(3), 2005: 861-77. [DOI:10.1193/1.1979502]