Lock-Up Devices or Shock Transmission Units and Snubbers

A damper with extremely restrictive orifices, these products are used to limit relative motion between masses during a transient event, while providing free motion in the normal mode. Snubbers were developed during the 1960s for the protection of large steam pipes in nuclear power plants. A true power plant snubber often incorporated internal flow control valves to accommodate site specific force-velocity profiles.
 
 
In the 1990s, Taylor Devices began using snubbers as locking devices to limit the relative motion of highway bridge sections under various types of transient motion, usually seismic in origin. When used on civil engineering structures, the product is usually called a Lock-Up Device (LUD), or Shock Transmission Unit (STU). Most applications have been in regions of low or moderate seismic risk, typically including seismic zones 1-3 in the U.S.. On bridges in these zones, the Lock-Up Devices allow essentially unrestricted motion when the bridge structure slowly expands and contracts thermally, yet locks the structural masses together under seismic or wind storm conditions.
 
 
Taylor Devices' Lock-Up Devices have the same basic dimensions as our fluid viscous dampers. Available in force ranges of 10 kip to 2000 kip, with thermal stroke capability of up to 120 inches.
  
 
500 kip LUDS for the Sidney Lanier Bridge (Georgia) Powerplant snubber, 150 tons output
 

STU Dimensions

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