Utilizing Earthquake Response Spectrum to Calculate the Floor Acceleration of Steel Frames

Authors
R. Karami Mohammadi
M. Mohammadi
K.N.Toosi University
Abstract
Abstract: The importance of non-structural components in seismic Performance Based Design of buildings is well known nowadays. In this research calculation of absolute acceleration applied on non-structural components located on floors of moment-resisting, eccentric braced and concentric braced frames subjected to earthquake ground motions has been studied. The results of nonlinear time-history analyses of 3, 5 and 7-story steel frames with 8 different periods and 5 reduction factors subject to 15 records of near-field earthquakes and 15 records of far-field earthquakes has been used to investigate the effects of different parameters on absolute acceleration induced in each floor of the structures. The effect of inelastic behavior of system, natural periods of primary and secondary systems, structural system type and near-field ground motions have been studied with use of modified shear-building models of steel frames. The shear building models are set to have an equivalent lateral force-deformation behavior in each story to the one’s of given steel frames. Reliability of these models to estimate the maximum roof displacement and the maximum inter-story drift of steel frames has been investigated elsewhere through probabilistic analysis of the results obtained from comprehensive incremental dynamic analyses. The relationships that are presented in building codes to calculate the force applied on non-structural components has been usually expressed as a ratio of peak ground acceleration. This method of calculating of input acceleration to non-structural elements ignores the effect of frequency content of design ground motion. The results of the present study have been used to introduce a new method for calculation the force applied on non-structural components based on ground acceleration spectrum. In this method the input acceleration to non-structural components has been expressed as a ratio of earthquake response spectrum (instead of the peak ground acceleration). For this ratio which is entitled as “spectral amplification factor” two different expressions have been proposed for use in structures with linear and nonlinear behavior. This approach explicitly accounts for the frequency content of design earthquake in calculation of peak floor acceleration. The results of this study show that Euro-code 8 and ASCE 7-2010 recommendations need to modify specially for the precise location of the non-structural element and inelastic behavior of the structure. It has been demonstrated that structural system type does not significantly affect the amount of induced acceleration on each floor of steel frames.

Keywords

[1]  The Seismic Design Handbook; ch13; 2001.
[2]  American Society of Civil Engineers Minimum Design Loads for Buildings and Other Structures ASCE 7; (2010).
[3]  Eurocode 8: Design of structures for earthquake resistance; (2003).
[4]  Uniform Building Code ; Volume 2; Structural Engineering Design Provisions; (1997).
[5]  Sadeghzadeh-Nazari; M. ; Ghafory-Ashtiany; M. ; “Seismic Design Force Requirements for Secondary Systems in Buildings” ; 6th International Conference on Seismology and Earthquake Engineering; may (2011).
[6]  Oropeza ; M. ; Favez ; P. ; Lestuzzi; P. ; “Seismic Response of Nonstructural Components in case of Nonlinear Structures Based on Floor Response Spectra Method” ; Bull Earthquake Eng, 8:387–400; 2010.
[7]  Medina ; R. A. ; Sankaranarayanan ; R. ; Kingston K. M.; “Floor Response Spectra for Light Components Mounted on Regular Moment-Resisting Frame Structures” ; 2006.
[8]  Braga ; F. ; Manfredi ; V. ; Masi ; A. ; Salvatori ; A. ; Vona; M. ; “Performance of Non-structural Elements in RC Buildings During the L’Aquila” ; 2009 earthquake; Bull Earthquake Eng 9:307–324; 2011.
[9]  Shooshtari ; M. ; Saatcioglu ; M. ; Naumoski ; N. ; Foo ; S. ; “Floor Response Spectra for Seismic Design of Operational and Functional Components of Concrete Buildings in Canada” ; Can. J. Civ. Eng. 37: 1590–1599; 2010.
[10]  Blackman; J. ; “Defense Nuclear Facilities Safety Board” ; December 2009.
[11]  Subramanian ; K. V. ; SpidharGopal ; P. ; Sudarsan ; R. P. ; “A Practical Approach for Floor Response Spectra Generation in Nuclear Power Plants”; 1999.
[12]  Varpasuo; P. ; “The Development of the Floor Response Spectra using Large 3D Model”; Nuclear Engineering and Design Vol. 192:229–241; 1999.
[13]  Kitada; Y. ; Hattori; K. ; Ogata ; M. ; Kanda ; J. ; “Stochastic Seismic Floor Response Analysis Method for Various Damping Systems” ; Nuclear Engineering and Design; Vol. 128:247-257; September 1990.
[14] فیوض; ع. ; غفوری آشتیانی; م. ; “روش ساده تحلیل سیستم های ثانویه”، The Construction Industry Portal of Iran، 2003.
[15]  Chen ; Y. ; Soong ; T. T. ; “STATE-OF-THE-ART REVIEW Seismic Response of Secondary Systems” ; Engineering Structures; Vol. 10; April 1988.
[16]  Singh ; M. P. ; Suarez ; L. E. ; Matheau ; E. E. ; Maldonado ; G. O. ; “Simplified Procedures for Seismic Design of Nonstructural Components and Assessment of Current Code Provisions”; Technical Report NCEER 93-0013; August 1993.
[17]  Villaverde ; R. ; “Earthquake Engineering from Engineering Seismology to Performance Based Engineering CRC Press” ; Ch19; 2004.
[18]  Viti ; G. ; Olivieri ; M. ; Travi ; S. ; “Development of Non-Linear Floor Response Spectra” ; Nuclear Engineering and Design; Vol. 64:33-38; April 1981.
[19]  Peters ; K. A. ; Schmitz ; D. ; Wanger ; U. ; “Determination of Floor Response Spectra on The Basis of the Response Spectrum Method”; Nuclear Engineering and Design; Vol. 44:255-262; November 1976.
[20]  Uma ; S. ; Zhao ; J. ; King ; A. ; “Floor Response Spectra for Frame Buildings under Ultimate and Serviceability Limit States”; Don't Mess with Structural Engineers ASCE; 2009.
[21]  Miranda ; E. ; Taghavi ; SH. ; “Approximate Floor Acceleration Demands I: Multistory Buildings. I: Formulation; Journal of Structural Engineering” ; Volume 131; April 2004.
[22]  Miranda ; E. ; Taghavi ; SH. ; “Approximate Floor Acceleration Demands in Multistory Buildings. II: Applications; Journal of Structural Engineering”; Volume 131; April 2004.
[23]  Chaudhuri ; S. R. ; Villaverde; R. ; “Effect of Building Nonlinearity on Seismic Response of Nonstructural Components: A Parametric Study” ; Journal Of Structural Engineering ASCE; April 2008.
Modares Civil Engineering journal
Volume 13, Issue 1
March and April 2013
Pages 89-99