Large-Scale Testing to Study the Effects of Critical Parameters on the Aerodynamic Behavior of Long Span Bridges

Abstract

All rights reserved.iv DEDICATION This dissertation is dedicated to my wife, Maryam Asghari Mooneghi. There is an old quote saying that "No man succeeds without a good woman behind him". I should say that this is more than true in my case. My wife not only was my support as my best friend during my career, let me share with her the difficulties I faced and helped me relax, but also was a great scientist with whom I was able to discuss about challenging problems. There were some days I was near to a complete surrender, but her sacrifices let me stand up again and continue the way. I am always grateful to my wife, not only as my wife but as my closest friend and I want to thank her for her supports during the precious time that we spent together at FIU and at Wall of Wind to get our PhDs. Wind tunnel testing is a well-established practice to evaluate the stability of bridges against wind loads. In order to study the response of the prototype in laboratory, dynamic similarity requirements should be satisfied. One of the parameters that is normally violated in wind tunnel testing is Reynolds number. In this dissertation, the effects of Reynolds number on the aerodynamics of a double deck bridge were evaluated by measuring fluctuating forces on a motionless sectional model of a bridge at different wind speeds representing different Reynolds regimes. Also, the efficacy of vortex mitigation devices was evaluated at different Reynolds number regimes. Not only the flow properties play an important role on the aerodynamic response of the bridge, but also the geometry of the cross section shape is expected to have significant effects. In this dissertation, the effects of deck details, such as width of the gap between the twin decks, and traffic barriers on the aerodynamic characteristics of a twin deck bridge were investigated, particularly on the vortex shedding forces with the aim of clarifying how these shape details can alter the wind induced responses.