Shock-Transmission Units are also well-known as Temporary Connection Devices (TCD) or Lock-up Devices, and the exterior is similar to Fluid Viscous Dampers (FVD). The STU locks the adjacent structure rigidly during high impact behavior. It is different from FVD, which offers energy dissipation under earthquake.
The STU links separated structures together into one rigid structure to strengthen resistance to earthquake.
A typical performance figure is shown to the right. When a slow speed (6.5mm / hour) acts on the STU, the output force is less than 10% of the nominal force.
Application & Connection
When installed, the STU shortens and elongates along with the bridge, and the STU locks the bridge with the pier and abutment during an earthquake.