Experimental determination of aeroelastic and aerodynamic parameters of long-span bridges

Determination of aeroelastic and aerodynamic parameters through wind tunnel investigations is an essential component of the aerodynamic modeling of bridges. With super-long span bridges being constructed and planned for future, the aerodynamic mechanisms have become even more complex than before. Recently developed multi-mode flutter and buffeting analyses have significantly advanced the capabilities of the existing analytical methods. However, availability of all the aerodynamic and aeroelastic parameters and other relevant descriptors is important for investigation of complex modal interactions and aeroelastic coupling expected in such long and flexible bridges.; A 3-DOF suspension system for wind tunnel section model tests was implemented and all the eighteen flutter derivatives were estimated for a streamlined (Tsurumi) and a bluff (Deer Isle) bridge deck sections. The experimentally obtained flutter derivatives were compared with those calculated using pseudo-steady approximations. The interrelations and approximate equivalences among the flutter derivatives of a low speed airfoil were analytically derived and the possibility of such interrelations among flutter derivatives of bridges was investigated. The sensitivity of aeroelastic parameters to seemingly small geometric changes was studied through a series of experiments on Tsurumi bridge by changing the modeling of its guard railings.; The buffeting forces on both the Tsurumi and the Deer Isle bridge deck section models were investigated in smooth and turbulent flow incoming conditions. The existing quasi-static formulation of buffeting forces was examined. Based on the observations of the effect of incident turbulence on the body-initiated or signature turbulence, a new approach to model buffeting forces and aerodynamic admittance has been suggested.