Aerodynamic Behavior of Long-Span Cable-Stayed Bridges

In this paper, we study the behavior of the aerodynamic fan-shaped scheme of cable-stayed bridges under wind load. A numerical analysis is developed, based upon time integration of the motion equations of the discretized structure. The main structural nonlinearity arising from the stress–strain stay's constitutive equation is taken into account together with the nonlinear effects that arise assuming a nonstationary model for aerodynamic loads. A Newmark's type algorithm is used to discuss first the problem of free oscillations in still air, and to determine next the critical wind speeds, both in the case of A-shaped and of H-shaped towers. For the latter case, the overall discrete model is validated by comparison with analytical results obtained by a continuous model, already developed [5, 7]. The performance improvement of the structural behavior obtained by using A-shaped towers is numerically investigated by using the discrete model proposed here.