Section J3.1/Bolted Connections
AISC 360-22 Section J3 covers bolted connection design including bolt grades, spacing, edge distances, and strength calculations.
Bolts used in structural connections must conform to ASTM standards for the specified grade (A325/F1852 or A490/F2280, now designated as Group A and Group B per ASTM F3125). Bolt holes must conform to the provisions of Section J3.2. The minimum bolt spacing is 2-2/3 times the bolt diameter. Minimum edge distance is based on bolt diameter per Table J3.4. Bolt pretension is required for slip-critical connections and connections subject to fatigue or tension.
Why this section exists
Bolted connections are the most common method of joining structural steel members. The design provisions ensure that bolts have adequate spacing to develop their full strength, sufficient edge distance to prevent tearout, and proper installation tension where required. A connection failure can be sudden and catastrophic, making the specification and detailing of bolts one of the most critical aspects of structural steel design.
What plan reviewers look for
Plan reviewers check connection details for bolt size, grade, quantity, spacing, and edge distance. They verify that the bolt grade is specified (not just "HS bolts") and that the connection type is identified (bearing, slip-critical, or pretensioned). They also check that the bolt strength calculations are consistent with the connection geometry shown on the details.
Common violations
Related AISC 360 requirements
Section J3.6 covers the tensile and shear strength of individual bolts. Section J3.8 covers the strength of bolt groups. Section J4.1 covers the affected elements (plates and connected members) at bolted connections. Section J10.1 covers concentrated forces at flanges and webs.