Case study and Evaluation of two steel bracing systems in the Bam earthquake and methods of retrofitting

Document Type : Original Article


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

2 M.Sc. Student, Department of Civil Engineering, K.N. Toosi University of Technology,Tehran, Iran

3 M.Sc. Student, Department of Civil Engineering, Sharif University of Technology, Tehran, Iran


In the seismically active countries such as Iran, there are many structures that have been designed and constructed in recent years that do not conform to the terms and provisions of the design codes. On 26 December 2003 at 1:57 GMT, the historical city of Bam, located in the south-eastern region of Kerman province in Iran, was shaken by a relatively strong and destructive earthquake. This earthquake clearly demonstrated that combination of relatively rigid load-bearing external brick walls and flexible internal steel columns, existing similarly in most other regions of the country, is quite hazardous. Also the use of steel beams and columns in buildings without observing proper seismic provisions showed no improvement over non-engineering designed buildings. In this research, two steel frame buildings which had been damaged in the bam earthquake were studied. The first building has bracing system in both directions and in the second building the bracing system only exist in one direction fallowed by infilled panel with saddlebag type connection(semi-rigid Khorjini connection) in opposite direction. In both buildings all the standard of criteria 2800 and Seismic provisions are considered. Nonlinear static analysis (Pushovers) and nonlinear time-history analysis are implemented on both structures. After determining the vulnerability of structures, using steel plates and viscous damper, the results show that retrofitted buildings with fluid viscous damper dissipate higher energy in comparison with the buildings retrofitted by the steel plate. Strengthening the existing buildings were investigated and compared with each others through three different methods: 1. replacing relatively strong bracing system with the relatively weaker bracing 2. Strengthening the columns by adding cover steel plates to the columns of building and 3. Global Strengthening bracing and columns system of buildings.


Main Subjects

[1] Wang, C.H.   and  Wen, Y.K.   “Seismic Response of 3-D Steel Buildings with Connection Fractures”, 12th World Conference on Earthquake Engineering, Paper No. 814. Auckland, New Zealand (2000).
[2] Minami, K.,  Sakai, J.,  and  Matsui, C. “Analysis of Damage of Stell Reinforced Concrete Building  Frames   by   1995   Hyogoken-Nambu Earthquake”, 12th World Conference on Earthquake Engineering, Paper No. 1127. Auckland, New Zealand (2000).
[3] Mahin, S.,     Malley, J.,    Hamburger, R.,    and Mahoney, M.  (2000).  “Overview of a  Program for  Reduction  of  Earthquake  Hazards  in  Steel Frame    Structures”, 12th World Conference on Earthquake Engineering, Paper No. 2541. Auckland, New Zealand (2000).
[4] Hamburger, R., Fouth D., and Cornell, C. “Performance Basis of Guidelines for Evaluation, Upgrade  and Design of Moment-Resisting  Steel Frames”, 12th World Conference on Earthquake Engineering, Paper No. 2543. Auckland, New Zealand (2000).  
[5] Malley, J.  and  Frank, K. “Materials and Fracture  Investigations  in the FEMA/SAC Phase2 Steel Project”, 12th World Conference on Earthquake Engineering, Paper No. 2544. Auckland, New Zealand (2000). 
[6] Krawinkler, H. “System Performance of Steel   Moment   Resisting   Frame   Structures”, 12th World Conference on Earthquake Engineering, Paper No. 2545. Auckland, New Zealand (2000).
[7] Roeder, C. “Performance  of  MomentResisting Connections”, 12th World Conference on Earthquake Engineering, Paper No. 2546. Auckland, New Zealand (2000).
[8] Mehrabian, A. and Haldar, A. “Some lessons learned from post-earthquake damage survey of structures in Bam, Iran earthquake of 2003”, Structural Survey, 23(3), pp. 180-192 (2005).
[9] Eshghi S, Zar´e M. Bam earthquake of 26 December 2003, Mw6.5: A Preliminary Reconnaissance report (2003). report english recc.html.
[10] Saedi Daryan, A., Bahrampoor, A. “Behavior of Khorjini connections in fire.”  Fire Safety Journal, 44(4), PP. 659-664(2009).
[11] Shakib, H., Dardaei, S., Joghan, Pirizadeh, M., Moghaddasi Musavi, A., “Seismic rehabilitation of semi-rigid steel framed buildings—A case study.” Journal of Constructional Steel Research, 67(6), PP. 1042-1049 (2011).
[12] Parsizadeh,F., Ibrion,M., Mokhtari, M., Lein, M., Nadim, M., "Bam 2003 earthquake disaster: On the earthquake risk perception, resilience and earthquake culture – Cultural beliefs and cultural landscape of Qanats, gardens of Khorma trees and Argh-e Bam." International Journal of Disaster Risk Reduction, 14(Part 4),pp. 457-469 (2015).
[13] Ibrion, M., Parsizadeh, F., Pakdaman Naeini, M., Mokhtari, M., Nadim, F., "Handling of dead people after two large earthquake disasters in Iran: Tabas 1978 and Bam 2003 – Survivors' perspectives, beliefs, funerary rituals, resilience and risk." International Journal of Disaster Risk Reduction, 11, pp. 60-77(2015).
[14] Farhoudian, A., Hajebi, A., Bahramnejad, A., Katz, C., "The Perspective of Psychosocial Support a Decade after Bam Earthquake: Achievements and Challenges." Psychiatric Clinics of North America, 36(3),pp. 385-402 (2013).
[15] Sadeghi, H., Manoochehri, M.F., Hosseini, K., Nakamura, T., Suzuki, S. "S-wave anisotropy in the aftershock region of the 2003 Bam, Iran, earthquake (Mw 6.5)." Tectonophysics, 594, pp. 128-136 (2013).
[16] Hosseini, M.A., de la Fuente, A., Pons, O. "Multi-criteria decision-making method for assessing the sustainability of post-disaster temporary housing units technologies: A case study in Bam, 2003." Sustainable Cities and Society, 20, pp. 38-51 (2016).
[17] Nicknam, A., Eslamian, Y. "A hybrid method for simulating near-source, broadband seismograms: Application to the 2003 Bam earthquake (Mw 6.5)." Tectonophysics, 487(1-4), pp. 46-58 (2010).
[18] Ramazi, H., Soltani Jigheh, H. "The Bam (Iran) Earthquake of December 26, 2003: From an engineering and seismological point of view." Journal of Asian Earth Sciences, 27(5), pp. 576-584 (2006).
[19] Hosseini Hashemi, B. and Jafari S.M.  “Performance of Batten Columns in Steel Buildings During the Bam Earthquake of 26 December”, JSEE: Special issue on Bam earthquake, pp. 101-109 (2003).
[20] Hosseini Hashemi B. and jafari S.M. “Experimental Evaluation of Cyclic Behavior of Batten Column", Journal of Constructional Steel Research, 78, pp. 88-96 (2012).
[21] Hosseini Hashemi, B. Ghafory Ashtiany, M. “Semi-rigid steel frame with “Khorjini” connections”. World Housing Encyclopedia report. Report ID 26 (2002).
[22] Hosseini Hashemi, B., Hassanzadeh, M. “Study of a semi-rigid steel braced building damaged in the Bam earthquake”, Journal of Constructional Steel Research, 64(6), pp. 704-721(2008).
[23] Galvo, A.S., Silva, A.R.D., Silveira, R.A.M. “Nonlinear dynamic behavior and instability of slender frames with semi-rigid connections.” International Journal of Mechanical Sciences, 52, pp. 1547-1562 (2010).