Do headed F1554 anchor bolts have a standard hex head or a heavy hex head?
ASTM F1554 does not specify whether the headed configuration is to be a standard hex pattern or heavy hex. There are three primary configurations covered by the ASTM F1554 specification which include straight rods, bent anchor bolts, and forged headed anchor bolts. Whether or not a headed anchor has a standard hex head or a heavy hex head can differ depending on the application. Since the head is embedded in the concrete, the designer or engineer may want a larger bearing surface than what a standard hex head would provide. If the head dimension is unspecified in the plans or specifications, it is best to leave the option of head style up to the manufacturer. Portland Bolt stocks headed F1554 anchor bolts and headed blanks in standard hex configurations and this flexibility may result in shorter lead times and less expensive bolts.
Although ASTM F1554 does not specify a head configuration, there are a number of other grades that do. This is important to keep in mind when specifying or ordering a particular grade of bolt.