Three-dimensional model of suspension bridges via a fully nonlinear continuum formulation

A fully nonlinear three-dimensional dynamic model of a suspension bridge under fairly general loading conditions is proposed. The nonlinear balance equations are obtained via a direct total Lagrangian formulation and the kinematics, for the deck and the two cables, include the finite displacements of the centroidal lines and the flexural and torsional finite rotations of the deck cross-sections (otherwise rigid in their own planes). The deformation parameters are nonlinear functions of the displacement gradients. The proposed model takes into account the fully nonlinear extensional-flexural-torsional coupling and examines the aeroelastic phenomena induced by static wind actions. With reference to the Hu Men Suspension Bridge, the critical wind velocities are calculated and compared with the results obtained via a linear analysis. The proposed applications are numerically performed via a finite element analysis.