Post flutter energy map for H-shaped bridge girder

In this study, with the help of three-degree-of-freedom random forced vibration device developed independently by Tongji University, high-precision measurement bridge aerodynamic force under large torsional amplitude was realized, and a potential energy spectrum established in consideration evolution effect that varies reduced velocity. As result, new research strategy for nonlinear flutter girders is proposed. Taking Old Tacoma Narrows Bridge as an example, mechanism phenomena at post-flutter state analyzed, wind-induced instability path its development were deduced. The results show response can be divided into two components according to spectrum. One component related effect, other mechanical damping ratio which helpful studying relationships between bifurcation flutter. At collapse Bridge, both nonlinearity variations have important contributions behavior terms effects. Variations torsion greatly improve performance bridge. Thus, structural displacement depends on competitive among ratio, rigidity, oncoming wind