How To Calculate Fastener Pullout

Another name for fastener is anchor bolt. People use anchor bolts and fasteners to anchor fixtures and materials to a foundation. Anchor bolt pull-out strength represents the force required to pull the bolt or fastener out of a foundation. The formulas needed to calculate the pull-out strength or force, depends on whether the foundation is concrete, steel, epoxy grout or some combination of materials, such as an anchor bolt embedded in epoxy grout that is attached to concrete.

Step 1

Calculate the pull-out strength of an anchor bolt embedded in epoxy grout and attached to a concrete foundation. To do it, use the formula F = D x 3.1415 x L x 800 psi — where F is bolt pull-out force — D is the grout hole diameter in inches — and L is the length of the grout hole.

For a D of 1 inch and a L of 4 inches, the bolt pull-out force is 10,050 lbs.

Step 2

Calculate the pull-out strength of an anchor bolt embedded in epoxy grout and attached to a steel foundation. To do it, use the formula F = D x 3.1415 x L x 1600 psi — where F is bolt pull-out force — D is the bolt diameter in inches — and L is the length of the bolt embedded in grout.

For a D of 1 inch and a L of 4 inches, the bolt pull-out force is 20,100 lbs

Step 3

Calculate the pull-out strength for an anchor bolt embedded in concrete. To do it, use the formula F = 800 psi x 3.1415 x 1.4142 x H^2 — where F is the bolt pull-out force — and H is the height from the top of the concrete to the tip end of the embedded bolt.

At a height (H) of 5 inches, the bolt pull-out force is 88,854 lbs