Efficient Reduced-Order Modeling Tools for Aeroelastic Predictions in Super Long-Span Bridges

Clarkson University, Potsdam NY

Investigators

Abstract

Wind-induced vibration of super-long-span bridges is a major concern for bridge designers. The wind can induce problematic vibration in two different ways. One way is the vibration induced by the periodic shedding of vortices that are enhanced by coupling with bridge motion; this is Vortex-Induced Vibration. The second way is the high-speed winds associated with severe storms; in this situation, flutter, among other fluid-structure interaction phenomena, is a major concern for its catastrophic nature. Thus there is a need to enhance the design technology through the development of improved computational capability that takes into account critical fluid mechanical phenomena that potentially induce problematical vibration of flexible bridges. A multi-disciplinary research effort devoted to advanced modeling of flexible long-span suspension bridges is planned. The research is targeted to the development, validation, and application of relatively sophisticated analysis tools to model highly unsteady flow over bridge decks associated with uniform and other important wind conditions and with the nonlinear flexible structures with torsional, bending, and axial modes excited. The main focus of this research is the development and application of new reduced-order models based on unsteady aerodynamic non-linear indicial functions to investigate long-span wind-induced bridge-structure vibration with two major outcomes: (i) the availability of powerful and affordable computational tools for aeroelastic predictions in bridges and (ii) an improved understanding of the aerodynamic instabilities, their triggering mechanisms and hints on how to prevent them. With the development of advanced aeroelastic modeling and computational techniques, engineers will be able to examine the inherent structural flexibility of long-span bridges coupled with aerodynamic nonlinearities due to fluid-structure interactions. The broader understanding of how elastic structures respond to wind should lead to new design criteria and insights for new design paradigms for long span bridges, wind turbines, skyscrapers, only to name a few. The results of this research will advance the knowledge of nonlinear fluid-structure interaction modeling of long- and super-long-span bridges and many other flexible structural systems exposed to aerodynamic loading. The results will also be useful to the engineer interested in retrofitting existing bridges with passive and active flow controls and other modifications as well as help engineers interested in developing improved structural health monitoring strategies.