Active Control and Stability of Cable-Stayed Bridge

The dynamic stability analysis of a typical two cable-stayed bridge implemented by the active feedback control systems has been carried out. The control systems (hydraulic servomechanisms) are connected to the existing four suspension cables so that under severe wind storm these cables serve also as active tendons. The bridge is subjected to both the buffeting and the self-excited loads as well as the control forces from the tendons (cables). The analysis has been applied to the Sitka Harbor Bridge in Alaska, as well as a hypothetical bridge with a much smaller stiffness. Numerical results indicate that the flutter speed of both bridges can be raised up to any desirable level or infinity by a suitable choice of the design values for the active control parameters.