Shock Transmission Unit (STU) / Lock-Up Device (LUD)

Product Introduction

The Shock Transmission Unit (STU), also known as a Lock-Up Device (LUD), is a velocity-based restraint and protection device. It is typically installed between structural components that experience relative displacement. When the two connected structures undergo slow relative movement, the STU can accommodate this displacement through its own extension and contraction. However, when the relative displacement velocity reaches its predefined lock-up threshold, the device rapidly engages and locks. At this point, no relative sliding occurs between its components; it effectively becomes a rigid link. This allows for the transfer of forces between adjacent structures, thereby preventing structural damage.

Its primary application is in engineering structures such as bridges and buildings, where it provides seismic resistance and displacement restraint.