AISC Bolt Capacity Table

Quick reference for AISC 360 structural bolt capacities per LRFD design (phi = 0.75 for shear, phi = 0.75 for tension).

Bolt capacities below are based on nominal bolt strength from AISC 360-22 Table J3.2. Values assume threads included in shear plane (N condition) or threads excluded (X condition) as noted.

A325 Bolt Shear Capacity (phiRn, kips) — Single Shear

Bolt material: ASTM F3125 Grade A325, Fnv = 54 ksi (threads included), 68 ksi (threads excluded).

A490 Bolt Shear Capacity (phiRn, kips) — Single Shear

Bolt material: ASTM F3125 Grade A490, Fnv = 68 ksi (threads included), 84 ksi (threads excluded).

A325 & A490 Double Shear Capacity (phiRn, kips)

Double shear capacity = 2 x single shear. Applies when the bolt passes through three connected plates with two shear planes.

A325 & A490 Bolt Bearing Capacity (phiRn, kips/bolt)

Bearing capacity per bolt at standard holes, assuming clear distance Lc = 2d (minimum edge distance). phi = 0.75, connected material Fy = 50 ksi (A992), Fu = 65 ksi.

Calculated as phi x 1.2 x Lc x t x Fu where Lc = edge distance minus half the hole diameter. Actual bearing capacity depends on specific edge distance, hole type, and material grade.

Slip-Critical Capacity (A325SC & A490SC)

For slip-critical connections (prevented from slip at service loads), Class A faying surface (mu = 0.30):

Values assume standard holes, Class A surface, no filler plates. Slip-critical design per AISC Section J3.8. phi = 1.0 for slip prevention at service loads.

A325 Bolt Tension Capacity (phiRn, kips)

AISC 360-22 Table J3.2: Fnt = 90 ksi for A325.

A490 Bolt Tension Capacity (phiRn, kips)

AISC 360-22 Table J3.2: Fnt = 113 ksi for A490.

Notes on Usage

• phi factor: 0.75 for both shear and tension (LRFD)
• Bearing capacity governs at low edge distances — check separately per Table J3.6
• Bolt pretension for slip-critical connections: refer to AISC 360 Table J3.1
• Combined tension + shear: Interaction equation per AISC 360 Section J3.7 applies when both are present
• For ASD, divide phiRn by 1.50 (omega = 2.00)

A325 vs A490 Capacity Comparison Table by Diameter

The following table compares A325 and A490 bolt capacities across all standard diameters for single shear (threads included, N condition):

A490 bolts are consistently 26% stronger in shear (Fnv ratio 68/54 = 1.26) and 25% stronger in tension (Fnt ratio 113/90 = 1.26) than A325 bolts. However, A490 bolts cannot be galvanized and require more careful installation.

Single Shear vs Double Shear — When Each Applies

The number of shear planes depends on the connection geometry:

Important caveat: Double shear doubles the bolt shear capacity but does NOT double the bearing capacity. Bearing must be checked on each connected ply independently. A thin gusset plate in a double-shear connection may still fail in bearing even though the bolt shear is adequate.

Double Shear Worked Example

Given: 7/8" A325-N bolt in double shear, connecting a 1/2" gusset plate between two 3/8" splice plates. Connected material is A992 (Fu = 65 ksi).

Bolt shear: phiRn = 2 x 0.75 x 54 x 0.601 = 48.7 kips (double shear).

Bearing on 1/2" gusset: phiRn = 0.75 x 2.4 x 0.875 x 0.50 x 65 = 51.2 kips (with adequate edge distance). Bearing does not govern.

Bearing on each 3/8" splice plate: phiRn = 0.75 x 2.4 x 0.875 x 0.375 x 65 = 38.4 kips per plate. Total bearing from both splice plates = 2 x 38.4 = 76.8 kips. Bearing OK.

Result: Bolt shear governs at 48.7 kips.

Bearing Capacity per AISC J3.10 — Detailed Analysis

Bearing capacity depends on the clear distance Lc from the bolt hole edge to the plate edge (or to the adjacent hole edge). AISC 360-22 Section J3.10 provides two bearing equations:

When Deformation at Service Load is a Design Consideration (Most Common)

phiRn = 0.75 x 1.2 x Lc x t x Fu    (for each bolt, limited to phiRn <= 0.75 x 2.4 x d x t x Fu)

When Deformation at Service Load is NOT a Design Consideration

phiRn = 0.75 x 1.5 x Lc x t x Fu    (for each bolt, limited to phiRn <= 0.75 x 3.0 x d x t x Fu)

Bearing Capacity Table — 3/4" Bolts in A992 Steel (Fu = 65 ksi)

For thin plates (1/4") with minimum edge distance, bearing governs over bolt shear. For thicker plates (1/2"+) with adequate edge distance, bolt shear typically governs.

Combined Shear and Tension Interaction

When bolts carry both shear and tension simultaneously (e.g., in moment end plates or bracket connections), AISC 360 Section J3.7 requires an interaction check:

Interaction Equation

When fv >= 0.2 x Fnv:
  (fv/Fnv)^2 + (ft/Fnt)^2 <= 1.0

Alternative (for LRFD):
  F'nt = 1.3 x Fnt - (Fnt / (phi x Fnv)) x fv  <= Fnt

Where fv = required shear stress and ft = required tension stress.

Interaction Capacity Table — 3/4" A325-N Bolt

This illustrates why moment end plate connections require careful bolt group analysis: the bolts must resist both the shear from the beam reaction AND the tension from the moment couple. For connections with high moment-to-shear ratios, the tension demand dominates and may require A490 bolts or larger diameters.

Bolt Group Capacity Quick Reference

For common connection types, the following table provides approximate bolt group capacities:

Note: Eccentric bolt group capacities are lower than the straight sum shown above. For eccentric connections (e.g., single-plate shear connections with eccentricity between bolt line and weld line), use the instantaneous center of rotation method per AISC Manual Part 7.

Pretensioned vs Snug-Tight Conditions

AISC 360-22 Table J3.1 specifies when bolt pretensioning is required:

Minimum Pretension Forces (AISC Table J3.1)

Pretension is approximately 70% of the specified minimum tensile strength of the bolt. For slip-critical connections, the clamping force from pretension creates friction resistance on the faying surface, which must meet the surface class requirements (Class A: mu = 0.30, Class B: mu = 0.50, Class C: mu = 0.35).

Design Strength Summary Tables

A325-N Complete Design Strength (phiRn per bolt)

A490-N Complete Design Strength (phiRn per bolt)

For A490 bolts 1-1/8" and larger, bearing on 1/2" plate starts to govern over bolt shear, indicating that thicker plates or higher-strength steel may be needed to develop the full bolt capacity.

Regional standards

Reference pages organized by design code jurisdiction:

• Australian bolt-capacity-table
• European bolt-capacity-table
• UK bolt-capacity-table

Frequently Asked Questions

What is the difference between A325 and A490 bolts? A325 (ASTM F3125 Grade A325) has Fnt = 90 ksi in tension and Fnv = 54 ksi in shear (threads included). A490 (ASTM F3125 Grade A490) has Fnt = 113 ksi in tension and Fnv = 68 ksi in shear — roughly 25% stronger. A490 bolts must not be galvanized and require special attention in slip-critical connections. Use A325 for most structural connections; A490 where bolt count or size would otherwise be excessive.

What does "threads included" vs "threads excluded" mean? The shear plane cuts through the threaded portion of the bolt (N condition, threads included) or the unthreaded shank (X condition, threads excluded). The threaded area is smaller than the gross area, so N-condition capacity is lower. Most standard connections use N-condition (threads are in the shear plane by default); X-condition requires deliberate detailing to ensure threads are outside the shear plane, confirmed by inspection.

When does bolt bearing capacity govern over bolt shear? Bearing capacity (phi × Rn = phi × 2.4 × Fu × d × t) governs when the edge distance or plate thickness is small relative to the bolt diameter. Common trigger: edge distance < 1.5d or thin gusset plates. AISC 360 Table J3.6 gives bearing values; always check bearing at each connected ply separately. For connections with standard holes and adequate edge distance, shear typically governs.

How do I account for combined tension and shear in a bolt? Use AISC 360 Section J3.7. When shear stress frv exceeds 20% of the bolt shear capacity, the available tension capacity is reduced. The interaction equation: F'nt = 1.3×Fnt − (Fnt/phi×Fnv) × frv ≤ Fnt. Check this for bracket plates, moment end plates, and any connection where the bolt load has both a horizontal and vertical component.

What phi factor applies to bolt capacity in LRFD? AISC 360 uses phi = 0.75 for both bolt shear and bolt tension. For slip-critical connections (where the joint must not slip at service load), a separate check uses phi = 1.0 for Class A faying surfaces or phi = 1.13 for Class B, applied to the slip resistance — not the bolt strength.

How many 3/4 in A325 bolts do I need for a 100-kip shear connection? A single 3/4 in A325 bolt in single shear with threads included (N condition) has φRn = 17.9 kips. For 100 kips: n = 100 / 17.9 = 5.6 → use 6 bolts minimum. Always check bearing on the connected material separately. For A36 plate (Fu = 58 ksi) with standard holes and adequate edge distance: φRn_bearing = 0.75 × 2.4 × 58 × 0.75 × t per bolt. For 3/8 in plate: 0.75 × 2.4 × 58 × 0.75 × 0.375 = 29.3 kips/bolt — bearing controls only if the plate is very thin.

What is the A490 tension capacity for a 1 in bolt, and when should I use A490? A 1 in A490 bolt has φRn in tension = 0.75 × 113 × 0.606 = 51.4 kips (using the tensile stress area of 0.606 in²). Compare to A325: 0.75 × 90 × 0.606 = 41.0 kips — A490 is 25% stronger in tension. Specify A490 when bolt count is limited by geometry (e.g., moment end plates with fixed bolt pattern), when bolt diameter is constrained, or where A325 bolts would require an impractically large group to resist high tension demands such as in rigid moment connections.

How do I calculate double-shear bolt capacity? For double shear, multiply the single-shear capacity by 2. A 7/8 in A325 bolt in double shear (threads included): φRn = 2 × 24.4 = 48.8 kips. Double shear occurs in gusset plates sandwiched between two connection elements (e.g., a brace-to-gusset connection). Note that bearing must also be checked on each individual ply — the bearing capacity is not doubled unless each ply is thick enough to develop its own bearing resistance.

Run This Calculation

→ Bolted Connections Calculator — full bolt group capacity with shear, bearing, block shear, and eccentric bolt group checks per AISC 360.

→ Gusset Plate Calculator — gusset plate and weld group design including bolt layout and block shear at connections.

Calculate Bolt Group Capacity

Use the Bolted Connection Calculator to check bolt group capacity with full AISC 360 derivation steps, including instantaneous centre of rotation for eccentric bolt groups.

Related pages

• Bolt Torque Chart — A325, A490, Metric 8.8/10.9, SAE Gr5/Gr8
• Bolt Spacing & Edge Distance — Minimum Requirements
• Bolt Hole Sizes — AISC Standard, Oversize & Slotted
• Steel Connection Design — Bolted and Welded Limit States
• Bolted Connections Calculator — full bolt group capacity with eccentric bolt group checks
• Gusset Plate Calculator — gusset plate and bolt group design including block shear
• Steel Grades Reference — A36, A572, A992 material properties for connection plates
• Bolt grades reference
• AISC bolt hole sizes
• AS 4100 Bolt Group Design
• Steel Fy and Fu reference table

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