Series of Full-Scale Field Vibration Tests and Bayesian Modal Identification of a Pedestrian Bridge
Publication: Journal of Bridge Engineering
Volume 21, Issue 8
Abstract
Many spectacular pedestrian bridges were designed and constructed recently. Owing to their special shapes, it is expected that various types and a wide range of vibration frequency components will be induced by pedestrians. To avoid accidents and reduce risk, the vibration characteristics of pedestrian bridges during their service life must be carefully assessed. The most direct and reliable way to study the vibration characteristics of a structural system is through field vibration tests. In this paper, a series of full-scale field vibration tests (including ambient, forced, and free vibration tests) were carried out on a pedestrian bridge at City University of Hong Kong (CityU). The difficulties encountered in the field tests are reported. The recently developed Bayesian methods were utilized to determine the modal parameters of the bridge based on measurements from all three kinds of tests. In addition to the most probable values (MPVs) of modal parameters, the associated posterior uncertainties were also analytically calculated. Four modes were identified, including three vertical bending modes and one torsional mode. The accuracy of the identified modal parameters was assessed through the posterior uncertainty. Because the amplitudes of the vibration in the three kinds of tests were different, the modal parameters determined from these kinds of tests were compared and discussed. Suggestions related to the proper use and potential vibration problems during the lifecycle of pedestrian bridges were provided based on the analysis results.
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Acknowledgments
The paper is sponsored by the National Natural Science Foundation of China (Grant No. 51508407 and 51508413), Fundamental Research Funds for the Central Universities, China (Grant No. 2014KJ040), Shanghai Pujiang Program (Grant No. 15PJ1408600), and Research Grants Council of the Hong Kong Special Administrative Region, China [Project No. 9041758 (CityU 110012)]. The authors thank Siu-Kui Au, professor at the University of Liverpool, for giving valuable suggestions during the field tests. The authors thank the anonymous reviewers for their constructive comments.
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Published In
Journal of Bridge Engineering
Volume 21 • Issue 8 • August 2016
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Dec 2, 2014
Accepted: Sep 15, 2015
Published online: Feb 1, 2016
Discussion open until: Jul 1, 2016
Published in print: Aug 1, 2016
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