A Shear-based Adaptive Pushover Procedure for Moment-resisting Frames

Document Type : Research Article

Authors

Department of Civil Engineering, Isfahan University of Technology, Esfahan, Iran

Abstract

The effects of higher modes are neglected in conventional pushover analysis procedures. Among the improved pushover methods, the adaptive pushover procedures are attractive for their multi-mode capability. In such procedures, the dynamic characteristics of buildings are updated in each stage of analysis consistent with the extent of the non-linear action throughout the structure. In this paper an adaptive pushover procedure is introduced that works with inter-story shear forces. It is compared with the conventional adaptive pushover methods where story accelerations or displacements are the bases of analysis. In the proposed method, the inter-story shears are calculated and updated based on the current dynamic characteristics of structure at each analysis step. They are then converted to the equivalent lateral forces for pushover analysis. Through using a correction factor based on the fundamental period of the building, a procedure is also developed for modifying the story drifts. Comparison with the average results of exact nonlinear dynamic analysis of a number of buildings under several earthquakes shows accuracy similar to the most precise procedure within the available conventional adaptive pushover methods. For the comparative analysis, 5, 10 and 15-story buildings and seven ground motions are utilized. Moreover, the proposed method is practically more adaptable to the current commercial softwares.

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Main Subjects


[1] Applied Technology Council, Seismic evaluation and retrofit of concrete buildings, ATC-40, Redwood City, California, USA. 1996.
[2] Building Seismic Safety Council, Prestandard and Commentary for the Seismic Rehabilitation of Buildings, Report FEMA-356, Washington, DC. 2000.
[3] Federal Emergency Management Agency, Improvement of nonlinear static seismic analysis procedures, FEMA 440, prepared by Applied Technology Council (ATC-55 Project), Washington, D.C. 2005.
[4] ASCE/SEI Seismic Rehabilitation Standards Committee, Seismic rehabilitation of existing buildings (ASCE/SEI 41-06), American Society of Civil Engineers, Reston, VA, 2007.
[5] P. Fajfar, P. Gaspersic, The N2 method for the seismic damage analysis of RC buildings, Earthquake Engineering & Structural Dynamics, 25(1) (1996) 31-46.
[6] S.A. Freeman, The capacity spectrum method, Proceedings of the 11th European conference on earthquake engineering, Paris, 1998.
[7] C. Casarotti, R. Pinho, An adaptive capacity spectrum method for assessment of bridges subjected to earthquake action, Bulletin of Earthquake Engineering, 5(3) (2007) 377-390.
[8] M.N. Aydinońülu, An incremental response spectrum analysis procedure based on inelastic spectral displacements for multi-mode seismic performance evaluation, Bulletin of Earthquake Engineering, 1(1) (2003) 3-36.
[9] T.F. Paret, K.K. Sasaki, D.H. Eilbeck, S.A. Freeman, Approximate inelastic procedures to identify failure mechanisms from higher mode effects, Proceedings of the eleventh world conference on earthquake engineering, 1996.
[10] K. Sasaki, S. Freeman, T. Paret, Multimode pushover procedure (MMP)-A method to identify the effects of higher modes in a pushover analysis, Proceedings of the 6th US national conference on earthquake engineering, Seattle, Washington, 1998.
[11] W. Tso, A. Moghadam, Pushover procedure for seismic analysis of buildings, Progress in Structural Engineering and Materials, 1(3) (1998) 337-344.
[12] A.K. Chopra, R.K. Goel, A modal pushover analysis procedure for estimating seismic demands for buildings, Earthquake engineering & structural dynamics, 31(3) (2002) 561-582.
[13] J.M. Bracci, S.K. Kunnath, A.M. Reinhorn, Seismic performance and retrofit evaluation of reinforced concrete structures, Journal of Structural Engineering, 123(1) (1997) 3-10.
[14] T. Lefort, Advanced pushover analysis of RC multi-storey buildings, Imperial College London United Kingdom, 2000.
[15] B. Gupta, S.K. Kunnath, Adaptive spectra-based pushover procedure for seismic evaluation of structures, Earthquake spectra, 16(2) (2000) 367-392.
[16] M. Requena, G. Ayala, Evaluation of a simplified method for the determination of the nonlinear seismic response of RC frames, Proceedings of the twelfth world conference on earthquake engineering, Upper Hutt, New Zealand., 2000.
[17] V.K. Papanikolaou, A.S. Elnashai, J.F. Pareja, Limits of applicability of conventional and adaptive pushover analysis for seismic response assessment, Mid-America Earthquake Center, Civil and Environmental Engineering Department, University of Illinois at Urbana-Champaign, (2005) 1-92.
[18] S. Antoniou, R. Pinho, Advantages and limitations of adaptive and non-adaptive force-based pushover procedures, Journal of Earthquake Engineering, 8(04) (2004) 497-522.
[19] S. Antoniou, R. Pinho, Development and verification of a displacement-based adaptive pushover procedure, Journal of Earthquake Engineering, 8(05) (2004) 643-661.
[20] K. Turker, E. Irtem, An effective load increment method for multi modal adaptive pushover analysis of buildings, Structural Engineering and Mechanics, 25(1) (2007) 53-73.
[21] J. Mao, C. Zhai, L. Xie, An improved modal pushover analysis procedure for estimating seismic demands of structures, Earthquake Engineering and Engineering Vibration, 7(1) (2008) 25-31.
[22] M. Poursha, F. Khoshnoudian, A. Moghadam, A consecutive modal pushover procedure for estimating the seismic demands of tall buildings, Engineering Structures, 31(2) (2009) 591-599.
[23] H.G. Pour, M. Ansari, M. Bayat, A new lateral load pattern for pushover analysis in structures, Earthquakes and Structures, 6(4) (2014) 437-455.
[24] G.E. Manoukas, A.M. Athanatopoulou, I.E. Avramidis, Multimode pushover analysis based on energy-equivalent SDOF systems, Structural Engineering and Mechanics, 51(4) (2014) 531-546.
[25] P. Sarkar, A.M. Prasad, D. Menon, Seismic evaluation of RC stepped building frames using improved pushover analysis, Earthquakes and Structures, 10(4) (2016) 913-938.
[26] X. Yu, D. Lu, B. Li, Estimating uncertainty in limit state capacities for reinforced concrete frame structures through pushover analysis, Earthquakes and Structures, 10(1) (2016) 141-161.
[27] K. Shakeri, M.A. Shayanfar, T. Kabeyasawa, A story shear-based adaptive pushover procedure for estimating seismic demands of buildings, Engineering structures, 32(1) (2010) 174-183.
[28] ANSI/AISC 360-16, Specification for Structural Steel Buildings, American Institute of Steel Construction, 130 East Randolph Street, Suite 2000, Chicago, Illinois 60601, 2016.
[29] Pacific Earthquake Engineering Research Center, PEER strong motion database, University of California, Berkeley Berkeley, CA, Disponivel online em: peer.berkeley.edu/products/strong_ground_motion_db.html. 2000.
[30] A. Campos-Costa, A. Pinto, European seismic hazard scenarios–an approach to the definition of input motions for testing and reliability assessment of civil engineering structures, JRC Special Publication No. X, 99 1999.
[31] SeismoSoft, SeismoStruct. A computer program for static and dynamic nonlinear analysis of framed structures, Available from URL: http://www.seismosoft.com. 2006.