Anchor Bolts

This cross section shows the top section of the anchor bolt or the 8 to 10 bolt diameters of stretch length needed. This length is from the bottom of the sleeve to the top of the base plate.  

  1. This is the area between the pipe sleeve and the anchor bolt. It is needed to allow for proper stretch of the anchor bolt and needs to be filed with a non-binding material prior to grout pour.  This material can be an expandable spray foam that will prevent grout from touching the anchor bolt and not allowing for stretch.  
  2. The pipe sleeve is generally 2 times the bolt diameter when set in new concrete.  If you are going to core drill for an anchor bolt this will need to be 3 times the bolt diameter and then filled with Chockfast Grey.  
  3. The rest of the anchor bolt needs to be protected from the grout that is above the pipe sleeve.  This is a foam insulation typically used on hot water pipes in a house.  If you don’t have this insulation you can use several wraps of duct tape as to not allow the grout to take profile on the anchor bolt preventing stretch.  
  4. This is the anchor bolt the main restraint to hold down the equipment.  Shown in this illustration is the 8 to 10 bolt diameters for stretch.  The bottom half the anchor bolt is shown in the detail below.  



The bottom half of the anchor bolt is the embedded length of the bolt.  This is generally 8 to 10 bolt diameters similar to the stretch length.  This would make the length of the anchor bolt approximately 16 to 20 bolt diameters in total length.  The bottom of the anchor bolt needs to have an anti-pull out device installed.  This is typically achieved with a fender washer and a nut installed on the bottom.  The nut is tac welded so it cannot be unthreaded.  If the anchor bolt is installed in a core drilled hold the anchor bolt will supported temporarily to allow for the Chockfast Grey to cure to hold the anchor bolt to the foundation.  If the anchor bolts are set in a foundation they can be tied to the rebar cage and have the pipe sleeve installed to allow for stretch.