ASTM F1554 anchor bolts can be straight rods (either fully threaded or threaded on each end), bent anchor bolts, or headed bolts.
Anchor Rods
Typically have a nut and/or anchor plate embedded in the concrete foundation to provide pull-out resistance. The nut and/or plate are often welded to the bottom of the anchor rod. Fully threaded rods can be used with epoxy in preexisting concrete slabs.
Bent Anchor Bolts
These anchor bolts have a 90° bend (right angle bend) that provides pull-out resistance. The smooth rod is bent to form an “L” shaped hook and is embedded in the concrete. This design provides the anchorage.
Headed Anchor Bolts
Headed bolts are turned upside down and poured into a concrete foundation with the threads projecting from the concrete and the head providing pull-out resistance. A square or round plate is often welded to the head of the bolt (for grades 36 and 55) to provide additional strength.