Bridge Aerodynamic Stability

With the collapse of the Tacoma Narrows Bridge a new area of study was born within the branch of Civil Engineering. This area, called Aeroelasticity, considers the effects of a bridge deck immerse in a wind flow. This has become more and more important due to the ever increasing length of spans in cable supported bridges. Even though this is a new subject within Civil Engineering, Aeroelasticity had already been studied for some time by the Aeronautical Industry. Because of this, most theories applied nowadays to deck cross sections have been adapted from aerofoils and flat plates’ behaviour. Aeroelasticity provides answers for what kind of displacements and forces occur when a bridge deck is subjected to a flow of air. It also defines which instability phenomena can occur in this situation. Furthermore, experimental procedures and simplified models have been developed to help with the evaluation of the stability of bridge decks. These are presented in this dissertation and are applied to practical cases to evaluate their validity.