Probabilistic Seismic Assessment of RC Buildings Considering Soft and Extreme Soft Story irregularities Subjected to Main Shock-Aftershock Sequences

Document Type : Research Article


1 Faculty of civil engineering, SHahrood university of technology

2 faculty of civil engineering, Shahrood university of technology,

3 Faculty of Civil engineering, Shahrood University of Technology, Shahrood, Semnan, Iran

4 Assistant Professor of Civil Engineering; Shahrood University of Technology


Recent Iranian earthquake damages like the damages caused by the Kermanshah earthquake revealed that RC buildings having soft-story irregularities experienced more seismic vulnerability. Moreover, earthquake aftershocks increased the seismic failures in past earthquake events. But they are not included in recent seismic design codes. In this article, for assessing the effects of soft-story irregularities and also the earthquake aftershocks, 3,5 and 8 story RC models having intermediate sway frames are designed and then modeled in OPENSEES and then IDA analysis is performed in order to produce the seismic fragility curves consistent with HAZUS definitions. The resulting seismic fragility curves revealed the influence of soft-story irregularities and also main shock-aftershock sequences on the vulnerability of considered RC models. By increasing the height of the RC structures, the effects of soft-story irregularities and the aftershocks decreased in the seismic vulnerability of the considered buildings.


Main Subjects

[1] ح. پهلوان, غ.ر. قدرتی امیری, ب. گنجوی, ارزیابی لرزه ای و توسعه منحنی شکنندگی ساختمان های بتن آرمه ایران با لحاظ اثر میان قاب‌های بنایی و ضعف سازه‌ای, 1393.
[2] R.P. Kennedy, A.C. Cornell, R.D. Campbell, S. Kaplan , H.F. Perla, Prob bilistic seismic s fety study of n existing nucle r power pl nt, Nucle r Eng & Design,  (1980).
[3] C.A. Kircher , W. Martin  Development of fragility Curve for Estimating of Earthquake damage Work Shopon Continuing Action to Reduce losses from Earthquake , Washington ,Dc : U.S.Geological Survey,  (1993).
[4] T. Anagnos, C. Rojahn, A. Kiremidjian, NCEER-ATC joint study on fragility of buildings,  (1995).
[5] A. Singhal, A.S. Kiremidjian, Bayesian updating of fragilities with application to RC frames, Journal of structural Engineering, 124(8) (1998) 922-929.
[6] A. Aziminejad, A. Moghadam, Effects of strength distribution on fragility curves of asymmetric single story building, in:  Ninth Canadian Conf. on Earthquake Eng., Ottawa, Ontario, Canada June, 2007.
[7] ع. ناصری, غ.ر. قدرتی امیری, ارزیابی احتمالاتی خسارت لرزه‌ای سازه‌های بتن آرمه با توسعه منحنی‌های شکنندگی, 1392.
[8] N. A, Seismic Vulnerability Assessment of the Iranian Existing RC Frame Structures with Probabilistic Methods, Pardisan University, Babolsar, 2013.
[9] ع. ناصری, ح. پهلوان, غ.ر. قدرتی امیری, ارزیابی  احتمالاتی خسارت لرزه ای سازه های بتن آرمه شمال ایران با استفاده از منحنیهای شکنندگی نشریه‌ی علمی پژوهشی مهندسی سازه و ساخت،( 1396).
[10] B. Silwal, O.E. Ozbulut, Aftershock fragility assessment of steel moment frames with self-centering dampers, Engineering Structures,  (2018).
[11] Y. Pang, L. Wu, Seismic Fragility Analysis of Multispan Reinforced Concrete Bridges Using Mainshock-Aftershock Sequences, Hindawi Mathematical Problems in Engineering,  (2018).
[12] S. Veismoradi, A. Cheraghi, E. Darvishan, Probabilistic mainshock-aftershock collapse risk assessment of buckling restrained braced frames, Soil Dynamics and Earthquake Engineering 115 (2018) 205–216,  (2018).
[13] مرکز تحقیقات ساختمان و مسکن آیین نامه طراحی ساختمان ها در برابر زلزله استاندارد2800, ویرایش چهارم, 1393.
[14] F.J. Vecchio, M.B. Emara, Shear Deformation in Reinforced Concrete Frames, ACI Structural, 89 (1992) 1.
[15] H. Pahlavan, M. Shaianfar, G.G. Amiri, M. Pahlavan, Probabilistic seismic vulnerability assessment of the structural deficiencies in Iranian in-filled RC frame structures, Journal of Vibroengineering, 17(5) (2015).
[16] J.B. Mander, M.J. Priestley, R. Park, Theoretical stress-strain model for confined concrete, Journal of structural engineering, 114(8) (1988) 1804-1826.
[17] A. Elnashai, R. Pinho, S. Antoniou, INDYAS-A Program for INelastic DYnamic Analysis of Structures, Engineering Seismology and Earthquake Engineering Report No. ESEE 00-2, Imperial College, London,  (2000).
[18] س.م. حسینی, ه. کنارنگی, کاربر نرم افزارOpenSees درمدلسازی و تحلیل سازه ها, انتشارات آزاده, 1392.
[19] Y. Li, R. Song, J.W. Van De Lindt, Collapse fragility of steel structures subjected to earthquake mainshock-aftershock sequences, Journal of Structural Engineering, 140(12) (2014) 04014095.
[20] M. Raghunandan, A. Liel, H. Ryu, N. Luco, S. Uma, Aftershock fragility curves and tagging assessments for a mainshock-damaged building, in:  Proceedings of the 15th World Conference on Earthquake Engineering, 2012.
[21] HAZUS-MH MR5, Multi-Hazard loss Estimation Methodology: Earthquake Model. Depariment of Homeland security, FEMA, Washington, D.C,, in, 2003.
[22] M. Banazadeh, S. Jalali, Probabilistic Seismic Demand Assessment of Steel Moment Frames with Sideplate Connections,  (2013).