Structural response analysis of a reinforced concrete building based on excitation of microtremors and passing subway trains

A period of more than 2 days measurements of the ambient seismic noise were conducted inside a reinforced concrete (RC) building in central Beijing. The temporal seismic array consists of 16 3-component short-period seismometers, with 2 on each floor, from the basements to the 7 th floor in this 7-story RC building. Two types of analysis were conducted to the measured data to extract the structural response of the building: 1) the horizontal to vertical (H/V) spectral ratio method to the continuous ambient noise; and 2) the seismic interferometry analysis with a deconvolution procedure to the seismic sources generated by the passing subway trains. Both analyses indicate the fundamental resonance frequency of this RC building is about 2.2 Hz in EW and 2.9 Hz in NS, with an unknown mode at the frequency of 5 Hz. The H/V analysis indicates that the major noise source comes to the building from EW direction, consisting with the urban traffic layout in central Beijing area. The seismic interferometry analysis of the structural response to the passing subway trains gives an estimate of the damping ratio of this RC building is about 0.17, a very efficient level of damping to resonant vibrations. We conclude that structural analysis using the ambient seismic noise (microtremors) as excitation input may provide an economical and flexible way to supplement the traditional strong ground motion analysis using only accelerograms in building vulnerability assessment to seismic hazard. This project is supported by Ministry of Science and Technology of China with Project No. 2006DFA21650 and the Institute of Earthquake Science (Project No. 0207690229).

[1]  Liu Chengqing,et al.  Damage Analysis of High-Rise Building under Seismic Load Based on Frequency Measurement , 2007 .

[2]  D. L. Anderson,et al.  Seismic excitation by the space shuttle Columbia , 1991, Nature.

[3]  Naoki Satake,et al.  Evaluation of vibration properties of high-rise steel buildings using data of vibration tests and earthquake observations , 1996 .

[4]  Li-Ling Hong,et al.  Empirical formula for fundamental vibration periods of reinforced concrete buildings in Taiwan , 2000 .

[5]  Lanbo Liu,et al.  Site effects on earthquake ground motion based on microtremor measurements for metropolitan Beijing , 2009 .

[6]  Peter Bormann,et al.  New Relationships between Vs, Thickness of Sediments, and Resonance Frequency Calculated by the H/V Ratio of Seismic Noise for the Cologne Area (Germany) , 2002 .

[7]  Felice Carlo Ponzo,et al.  Seismic waves generated by oscillating buildings: analysis of a release test , 2003 .

[8]  Stefano Parolai,et al.  Assessing the Vibrational Frequencies of the Cathedral of Cologne (Germany) by Means of Ambient Seismic Noise Analysis , 2006 .

[9]  G. Panza,et al.  Realistic Modeling of Seismic Wave Ground Motion in Beijing City , 2004 .

[10]  Maria Rosaria Gallipoli,et al.  Structure, soil-structure response and effects of damage based on observations of horizontal-to-vertical spectral ratios of microtremors , 2004 .

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

[12]  Clotaire Michel,et al.  Dynamic parameters of structures extracted from ambient vibration measurements : An aid for the seismic vulnerability assessment of existing buildings in moderate seismic hazard regions , 2007, 0710.1210.