Impact of Stochastic Traffic on Modified Cross-Section Profiles of a Slender Long-Span Bridge: Wind Tunnel Experimental Investigation
Publication: Journal of Engineering Mechanics
Volume 139, Issue 3
Abstract
For a slender long-span bridge, the global aeroelastic and aerodynamic phenomena, such as flutter stability and buffeting response, induced by wind turbulence significantly affect the safety and lifetime performance of the bridge. To investigate these phenomena, a wind tunnel experimental technique with bridge section models is typically required to identify some critical aerodynamic coefficients, such as flutter derivatives, which are dependent on the specific profile (shape) of a bridge cross section and the functions of reduced frequencies. Obviously, this practice is based on the assumption that the shape of the cross section of a long-span bridge does not vary over time. Such an assumption may not remain valid when the stochastic traffic on the bridge is considered, because of the simple fact that the presence of vehicles changes the profile of the bridge cross section. The current study aims to provide some insights through experimental assessment of traffic impacts on flutter derivatives of the modified bridge cross section because of the presence of traffic. A bridge section model with scaled vehicle models distributed on the bridge deck is tested in the wind tunnel following the simulated stochastic traffic flow. Several scenarios are tested to provide insights on the variations of the flutter derivatives over different sections along the bridge and at different time instants for the same location. In addition, some extreme situations, such as under evacuation or serious congestion, are also studied.
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Acknowledgments
This material is based on work supported by National Science Foundation Grant No. CMMI-0900253. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the investigators and do not necessarily reflect the views of the National Science Foundation. Dr. Jun Wu, the former graduate research assistant at Colorado State University (CSU), provided the traffic flow simulation results for the experimental study. Professor Bogusz Bienkiewicz at Colorado State University shared valuable advice throughout the wind tunnel experiments. All these contributions are greatly appreciated.
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© 2013 American Society of Civil Engineers.
History
Received: Oct 10, 2011
Accepted: Mar 29, 2012
Published online: Feb 15, 2013
Published in print: Mar 1, 2013
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