Evaluation of seismic reliability of steel moment resisting frames rehabilitated by concentric braces with probabilistic models

Document Type : Original Article

Authors

1 MSc of Civil Engineering, Faculty of Civil Engineering, Semnan University, Semnan, Iran

2 Associate Professor, Faculty of Civil Engineering, Semnan University, Semnan, Iran

Abstract

Probability of structure failure which has been designed by "deterministic methods" can be more than the one which has been designed in similar situation using probabilistic methods and models considering "uncertainties". The main purpose of this research was to evaluate the seismic reliability of steel moment resisting frames rehabilitated with concentric braces by probabilistic models. To do so, three-story and nine-story steel moment resisting frames were designed based on resistant criteria of Iranian code and then they were rehabilitated based on controlling drift limitations by concentric braces. Probability of frames failure was evaluated by probabilistic models of magnitude, location of earthquake, ground shaking intensity in the area of the structure, probabilistic model of building response (based on maximum lateral roof displacement) and probabilistic methods. These frames were analyzed under subcrustal source by sampling probabilistic method "Risk Tools" (RT). Comparing the exceedance probability of building response curves (or selected points on it) of the three-story and nine-story model frames (before and after rehabilitation), seismic response of rehabilitated frames, was reduced and their reliability was improved. Also the main effective variables in reducing the probability of frames failure were determined using sensitivity analysis by FORM probabilistic method. The most effective variables reducing the probability of frames failure are  in the magnitude model, ground shaking intensity model error and magnitude model error

Keywords


[1] FEMA, “State of art report on past performance of steel moment frame buildings in earthquakes”, Federal Emergency Management Agency, Report No, FEMA 355E, Washington, DC, (2000)
[2] Bruneau, M., Uang, C. M., Whittaker, A. S., “Ductile design of steel structures”, New York, (1998)
[3] Mahin, S. A., “Lessons from damage to steel buildings during the Northridge earthquake”, Engineering Structures, (1998)
[4] Watanabe, E., Sugiura, K., Nagata, K., Kitane, Y., “Performances and damages to steel structures during 1996 Hyogoken-Nanbu earthquake”, Engineering Structures, (1998)
[5] Nakashima, M., Inoue, K., Tada, M., “Classification of damage to steel buildings observed in the 1995 Hyogoken-Nanbu earthquake”, Engineering Structures, (1998)
[6] Naeim, F., Lew, M., Huang, C. H., Lam, H. K., Carpenter, L. D., “The performance of tall buildings during the 21 September 1999 chi-chi earthquake Taiwan”, The Structural Design of Tall Buildings, (2000)
[7] Di Sarno, L., Elnashai, A. S., Nethercot, D, A., “Seismic retrofitting of framed structures with stainless steel”, Journal of Constructional Steel Research, (2006)
[8] Guneyisi, E. M., "Seismic reliability of steel moment resisting framed buildings retrofitted with buckling restrained braces", Earthquake Engineering and Structural Dynamics, 41, p. p. 853-874, (2012).
[9] Ditlevsen, O., and Madsen,H. O.," Structural reliability methods", Wiley and Sons, Chichester, NewYork,NY. (1996).
[10] Mahsuli, M., Haukaas, T., "Seismic risk analysis with reliability methods, part I: Models", Structural Safety, 42, p. p. 63-74, (2013).
[11] Mahsuli, M., "Model-Manual for Rt.", University of Brithish Columbia, Vancover, www.inrisk.ubc.ca, (2012)
[12] Atkinson, G. M., and Boore, D. M., "Empirical ground-motion relations for subduction-zone earthquake and their application to Cascadia and other regions", Bulletin of the Seismological Society of America, 93(4), p. p. 1703-1729, (2003).
[13] Mahsuli, M., "Probabilistic modelsT methods and software for evaluating risk to civil infrastructure".Ph.D Thesis, The University of British Columbia (Vancouver), (2012).
]14[ آیین نامه استاندارد2800، (1384) آیین نامه طراحی ساختمانها در برابر زلزله، ویرایش سوم.‌
[15] McKenna, F., Scott, M. H., and Fenves, G. L., "Nonlinear finite-element analysis software architecture using object composition" ,J.Computer and Civil Engineering, 24(1), p. p.95-107, (2010).
[16] Menegotto, M., and Pinto, P. E, "Method of analysis forcyclically loaded R.C plan frames including change in geometry and non-elements behavior of elements under combined normal force and bending", Proc. Of IABSE Symposium on Resistance and Ultimate Deformability of Structures Acted on by Well Defined Repeated Loads,13, p. p. 15-22., (1973).
[17] FEMA, "Prestandard and commentary for the seismic rehabilitation of buildings", FEMA 356, Federal Emergency Management Agency, Washington, DC, (2000).