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Nonstructural component field testing method for the evaluation of seismic demand incorporating floor response spectrum

University of British Columbia

Nonstructural component (NSC) failures due to earthquake events can cause significant economic losses and even life-threatening hazards to occupants. In order to mitigate nonstructural seismic damages, it is critical to assess the seismic force demand which can be utilized to optimize the design of the NSC, and/or to assess methods of rehabilitation on anchorages to enhance seismic strength. The existing design codes and standards provide guidelines to calculate the minimum lateral earthquake force for designing a new NSC. However, they do not reflect the in-service condition of an existing NSC, which can vary significantly from when it was first installed. This study is intended to develop an easy-to-implement methodology to assess the seismic force demand of an existing NSC under normal operation. The procedure of the proposed methodology includes two principle phases: 1) field modal identification testing and 2) floor response spectrum analyses using a 3D finite element model (FEM). The practicality of this methodology was assessed through a case study on the U.B.C Hospital Koerner Pavilion building. In this study, the focus is on the machinery and equipment that are critical for the operation of a hospital. During the experimental stage, the fundamental frequencies and damping ratios of eight NSCs were identified. In the second phase, the horizontal floor response spectra (FRS) were constructed from the linear time history analysis results performed on a FEM. Finally, the FRS is used to obtain the lateral seismic force of each NSC corresponding to its dynamic properties. These forces were then compared with those obtained using the NBCC 2010 code equation to demonstrate the effectiveness of this method. Results from the case study provided evidence that the proposed method is overall a simple and effective tool for diagnosing the in-service modal properties of a NSC. The testing results can be easily applied in FRS analysis to obtain a more realistic nonstructural seismic force than that from the NBCC 2010 approach. The potential applications and limitations of the proposed methodology are also discussed in this dissertation to facilitate engineers to determine the suitability of this method to their specific projects.

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2014-04-24

Attribution-NonCommercial-NoDerivs 2.5 Canada

http://hdl.handle.net/2429/46567

Civil Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/2.5/ca/