Variability of the fixed‐base and soil–structure system frequencies of a building—The case of Borik‐2 building

Borik-2 is an IMS (Institute for Testing of Materials, Belgrade, Serbia)-type prefabricated 14-story reinforced-concrete building located in Banja Luka, Republic of Srpska (Bosnia, former Yugoslavia), and is a rare example of an instrumented building in Europe shaken by a significant number of earthquakes. This paper presents an analysis of its response to 20 earthquakes recorded in this building, and a comparison with results from previous full-scale tests and analyses. Only one of the 20 earthquakes (8/13/1981, M=5.4) could possibly have caused damage, but no structural damage was reported. For each of these earthquakes, the building fundamental fixed-base frequency f1 was computed from wave propagation travel times estimated by impulse response functions, and the soil–structure system frequency fsys was estimated from the peaks of the Fourier spectra of the response. The analysis suggests consistency of the estimates of fsys from the earthquake response data, from the forced vibration tests before the earthquakes, and ambient vibration tests conducted near the end of the earthquake sequence. The results suggest nonlinear but essentially ‘elastic’ behavior of the building for the amplitudes of motion covered by the data, and essentially linear soil–structure interaction. During the largest event, f1 and fsys decreased, respectively, by about 16 and 22% for EW motions, and by about 18 and 31% for NS motions, compared with the values before the earthquake from the small amplitude response. Comparison of f1 and fsys during the smaller events before and after EQ 11 event shows that f1 did not change, but fsys reduced permanently, by about 10% for EW and 15% for NS. Copyright © 2008 John Wiley & Sons, Ltd.

[1]  Kiyoshi Kanai,et al.  Some New Problems of Seismic Vibrations of a Structure. Part 1. , 1963 .

[2]  Hideji Kawakami,et al.  Wave Propagation Modeling Analysis of Earthquake Records for Buildings , 2004 .

[3]  Mihailo D. Trifunac,et al.  Wave propagation in a seven-story reinforced concrete building: II. Observed wavenumbers , 2001 .

[4]  J. E. Luco,et al.  On the apparent change in dynamic behavior of a nine-story reinforced concrete building , 1987 .

[5]  Charles R. Farrar,et al.  Damage identification and health monitoring of structural and mechanical systems from changes in their vibration characteristics: A literature review , 1996 .

[6]  Erdal Safak,et al.  Wave-Propagation Formulation of Seismic Response of Multistory Buildings , 1999 .

[7]  Katsutada Sezawa,et al.  Decay in the Seismic Vibrations of a Simple or Tall Structure by Dissipation of their Energy into the Ground , 1935 .

[8]  Charles R. Farrar,et al.  A summary review of vibration-based damage identification methods , 1998 .

[9]  Maria I. Todorovska,et al.  Effects of rainfall on soil–structure system frequency: Examples based on poroelasticity and a comparison with full-scale measurements , 2006 .

[10]  Darryll J. Pines,et al.  Damage detection in a building structure model under seismic excitation using dereverberated wave mechanics , 2003 .

[11]  Mihailo D. Trifunac,et al.  Propagation of earthquake waves in buildings with soft first floor , 1990 .

[12]  Mihailo D. Trifunac,et al.  Impulse response analysis of the Van Nuys 7‐storey hotel during 11 earthquakes and earthquake damage detection , 2008 .

[13]  Mihailo D. Trifunac,et al.  Earthquake damage detection in the Imperial County Services Building I: The data and time–frequency analysis , 2007 .

[14]  Mihailo D. Trifunac,et al.  Apparent Periods of a Building. II: Time-Frequency Analysis , 2001 .

[15]  E. Peter Carden,et al.  Vibration Based Condition Monitoring: A Review , 2004 .

[16]  M. I. Todorovskaa,et al.  Wave propagation in a seven-story reinforced concrete building : III . Damage detection via changes in wavenumbers , 2003 .

[17]  Hideji Kawakami,et al.  A New Method for Propagation Analysis of Earthquake Waves in Damaged Buildings: Evolutionary Normalized Input-Output Minimization (NIOM) , 2003 .

[18]  Maria I. Todorovska,et al.  Seismic Waves in Buildings with Shear Walls or Central Core , 1989 .

[19]  Mihailo D. Trifunac,et al.  On identification of Damage in Structures Via Wave Travel Times , 2001 .

[20]  Thomas H. Heaton,et al.  The Observed Wander of the Natural Frequencies in a Structure , 2006 .

[21]  Thomas H. Heaton,et al.  Propagating Waves in the Steel, Moment-Frame Factor Building Recorded during Earthquakes , 2007 .

[22]  Mihailo D. Trifunac,et al.  Re-occurrence of site-specific response in former Yugoslavia—part II: Friuli, Banja Luka and Kopaonik , 2003 .

[23]  Donald E. Hudson,et al.  Dynamic Tests of Full-Scale Structures , 1977 .

[24]  Katsutada Seazwa,et al.  16.Improved Theory of Energy Dissipation in Seismic Vibrations of a Structure , 1936 .

[25]  Roel Snieder,et al.  Extracting the Building Response Using Seismic Interferometry: Theory and Application to the Millikan Library in Pasadena, California , 2006 .

[26]  Mihailo D. Trifunac,et al.  Earthquake damage detection in the Imperial County Services Building III: Analysis of wave travel times via impulse response functions , 2008 .

[27]  Hoon Sohn,et al.  A review of structural health monitoring literature 1996-2001 , 2002 .

[28]  Mihailo D. Trifunac,et al.  Isolation of soil‐structure interaction effects by full‐scale forced vibration tests , 1988 .

[29]  Hideji Kawakami,et al.  Normalized input–output minimization analysis of wave propagation in buildings , 2003 .

[30]  Mihailo D. Trifunac,et al.  Wave propagation in a seven-story reinforced concrete building: I. Theoretical models , 2001 .

[31]  Mihailo D. Trifunac,et al.  Re-occurrence of site-specific response in former Yugoslavia—part 1: Montenegro , 2003 .

[32]  Mihailo D. Trifunac,et al.  Frequency dependent attenuation of strong earthquake ground motion , 1990 .

[33]  Mihailo D. Trifunac,et al.  Wave propagation in a seven-story reinforced concrete building: III. Damage detection via changes in wavenumbers , 2003 .

[34]  Mihailo D. Trifunac,et al.  Antiplane Earthquake Waves in Long Structures , 1989 .