🔩 Bolted Steel Connections

Written and maintained by the PhDino author · Last reviewed 21 September 2026 · Checked against 2 independent reference calculations · how PhDino checks its numbers

Related standards: AISC 360

Checking whether a group of bolts can transfer a shear load, considering both bolt shear and plate bearing.

A bolted connection can fail in more than one way, and the connection is only as strong as its weakest failure mode. Two of the most common checks are bolt shear (the bolt itself shearing through) and bolt bearing (the bolt crushing/tearing the plate material it bears against).

AISC 360 Chapter J covers this in detail. This calculator checks both modes and reports whichever governs — that's the connection's actual capacity.

Key formula

Bolt shear (per bolt): φR_n = φ × F_v × A_b
Bolt bearing (per bolt): φR_n = φ × 2.4 × d × t × F_u
Governing capacity = min(total shear, total bearing)

Variables

F_v

bolt shear stress (grade-dependent, e.g. A325 vs A490)

A_b

nominal bolt cross-sectional area

d, t

bolt diameter and connected plate thickness

F_u

ultimate tensile strength of the connected material

φ

LRFD resistance/reduction factor (0.75 here)

Notes & limitations

• Bearing capacity also depends on edge distance and bolt spacing (AISC J3.10 has reduced values for insufficient spacing) — this calculator assumes spacing is adequate.
• Slip-critical connections (where the joint must not slip at service loads) have an entirely different check based on friction, not covered here.