Smart bridge dampers (SBD)

A program of research has been conducted by the Center for Structural Control (CSC) at the University of Oklahoma to extend the service life of highway bridges, by retrofitting them with computer-controlled hydraulic stiffeners. The system consists of a moment producing assembly that bolts on to an existing bridge. The heart of the SBD system is a special hydraulic actuator that is outfitted with a motor controlled valve. The valve position is regulated to provide appropriate amounts of stiffness and damping to the bridge in order to minimize the stress caused by heavy trucks. Lyapunov´s second method was used to synthesize a control law. A simulation, using a simple pin-pin bridge, demonstrates the advantages of the new technology. The results indicate that the SBD system can reduce maximum stress by as much as 65%; thus, adding many years of additional service life to the bridge