Advances in modeling of aerodynamic forces on bridge decks

Aerodynamic forces on bridges are commonly separated into static, self-excited, and buffeting force components. By delving into the relationships among force descriptors for static, self-excited, and buffeting components, novel perspectives are developed to unveil the subtle underlying complexities in modeling aerodynamic forces. Formulations for airfoil sections and those based on quasi-steady theory are both considered. The time domain modeling of unsteady aerodynamic forces including their frequency-dependent characteristics and spanwise correlation is presented, which are often neglected in current time domain analyses due to modeling difficulty. A nonlinear aerodynamic force model is proposed to take into account the nonlinear dependence of the aerodynamic forces on the effective angle of incidence. The nonlinear aerodynamics may become increasingly critical when the aerodynamic characteristics of innovative bridge deck designs, with attractive aerodynamic performance, exhibit significant sensitivity with respect to the effective angle of incidence and with the increases in the bridge span. Clearly, in these cases one may be pushing the envelope of the current linear aerodynamics which has successfully served thus far. The synergistic review of the writers' recent work in bridge aerodynamics presented here, in light of the current state-of-the-art in this field, may serve as a building block for developing new analysis tools and frameworks for the accurate prediction of the response of long span bridges under strong wind excitation.