For equipment that is installed in earthquake prone areas, our seismic restraints may be used to secure equipment to the ground. These high strength stainless brackets attach to our leveling components to form a rigid connection that minimizes the build-up of seismic accelerations.

• Specifications
• Levelers

• made from high strength heat treated stainless steel
• all surfaces have an attractive bead blasted finish
• industrially cleaned, passivated, and individually bagged
• electropolishing available as an option

Apparatus: A steel frame with four leveler mounts and levelers was secured to a large shaker table with the restraints.  A crate filled with cement was placed on top. 

  Leveler Part Number: LV6311-AZ-SS
  Leveler Locations: 46.75 X 28.75 in.
  Leveler Extension: 1.25 in.
  CG Height: 22.0 inches

Tests: Tests were performed by an independent lab in accordance with the GR-63-CORE specification for a Pacific Rim Zone 4 earthquake.  This test simulates an earthquake with an 8.9 Richter magnitude and a peak G force of 2G's.  For perspective, this would rank among the top ten earthquakes since 1900 and the G forces are higher than any quake recorded in California.   

Results: At 2,000 lbs, the restraints and leveler studs showed no signs of yielding.  Subsequent testing at higher loads resulted in uncontrollable system resonances preventing a run at full strength.  For video of our test, see the movie below:

XA-LVRT-horizontal.wmv

Apparatus: A hydraulic press was fixtured to test a single restraint as shown.  The head of a leveler stud was attached to the end of the piston and secured to the restraint with the locknut.

Test: The piston was controlled by a PLC that was programmed move it rapidly up and down.  The peak pull force was over 2,500 lbs and the test was run for 30 seconds. 

Results: The restraint withstood testing with no signs of yielding.  For a movie, see the link below:

XA-LVRT-vertical.wmv