| 1/2 | 9/16 (0.5625) | 5/8 (0.625) | 1/16 | 1/8 | | 5/8 | 11/16 (0.6875) | 13/16 (0.8125) | 1/16 | 3/16 | | 3/4 | 13/16 (0.8125) | 15/16 (0.9375) | 1/16 | 3/16 | | 7/8 | 15/16 (0.9375) | 1-1/16 (1.0625) | 1/16 | 3/16 | | 1 | 1-1/16 (1.0625) | 1-1/4 (1.250) | 1/16 | 1/4 | | ≥ 1-1/8 | d + 1/16 | d + 5/16 | 1/16 | 5/16 |
Short-Slotted and Long-Slotted Hole Dimensions
| Bolt Diameter | Short-Slot (SSL) Width × Length | Long-Slot (LSL) Width × Length |
|---|---|---|
| 1/2 | 9/16 × 11/16 | 9/16 × 1-1/4 |
| 5/8 | 11/16 × 7/8 | 11/16 × 1-9/16 |
| 3/4 | 13/16 × 1 | 13/16 × 1-7/8 |
| 7/8 | 15/16 × 1-1/8 | 15/16 × 2-3/16 |
| 1 | 1-1/16 × 1-5/16 | 1-1/16 × 2-1/2 |
| ≥ 1-1/8 | (d+1/16) × (d+3/8) | (d+1/16) × 2.5d |
Most searched dimension: A 3/4 in. bolt requires a standard hole of 13/16 in. — 1/16 in. clearance each side for erection tolerance.
The Four Hole Types
Standard Holes (STD)
The default for all connections. Permitted in all connection types, no slip resistance reduction, best net section strength. Use unless erection tolerances demand otherwise.
Oversized Holes (OVS)
Restricted to slip-critical connections only. Provide 3/16 in. to 5/16 in. additional clearance for accumulated fabrication tolerances. Require plate washers on outer plies. Slip resistance reduced by 15% (h_sc = 0.85). Common in multi-story column splices and beam-to-column moment connections.
Short-Slotted Holes (SSL)
One-direction adjustment of approximately one bolt diameter. Permitted in both bearing and slip-critical connections. Slot perpendicular to load maintains full slip resistance. Common in beam web connections.
Long-Slotted Holes (LSL)
Approximately 2.5 bolt diameters of travel. Restricted to slip-critical connections only. Require full-coverage plate washers. Severe slip resistance penalties (h_sc = 0.70 parallel to load). Used for thermal expansion joints and connections with ongoing structural movement.
Net Area Hole Deduction
Per AISC 360 Section J3.2, the hole deduction = standard hole diameter + 1/16 in.:
| Bolt Dia. | STD Hole | Net Deduction |
|---|---|---|
| 1/2 | 9/16 | 5/8 (0.625) |
| 5/8 | 11/16 | 3/4 (0.750) |
| 3/4 | 13/16 | 7/8 (0.875) |
| 7/8 | 15/16 | 1 (1.000) |
| 1 | 1-1/16 | 1-1/8 (1.125) |
| 1-1/8 | 1-3/16 | 1-1/4 (1.250) |
| 1-1/4 | 1-5/16 | 1-3/8 (1.375) |
| 1-1/2 | 1-9/16 | 1-5/8 (1.625) |
The extra 1/16 in. accounts for material damage from punching. Do not use bolt diameter or hole diameter directly in net area calculations — always include the +1/16 in. damage allowance.
Slip Resistance Reduction Factors — AISC 360 Table J3.1
| Hole Type | Load Direction | h_sc Factor |
|---|---|---|
| Standard (STD) | Any | 1.00 |
| Oversized (OVS) | Any | 0.85 |
| Short-Slotted (SSL) | Any | 0.85 |
| Long-Slotted (LSL) | Perpendicular to slot | 0.85 |
| Long-Slotted (LSL) | Parallel to slot | 0.70 |
Bearing Strength by Hole Type
| Hole Type | Tearout Coefficient | Bearing Coeff. |
|---|---|---|
| Standard (STD) | 1.2 | 2.4 |
| Oversized (OVS) | 1.0 | 2.0 |
| Short-Slotted (any orientation) | 1.0 | 2.0 |
| Long-Slotted, load perpendicular | 1.0 | N/A |
| Long-Slotted, load parallel | 1.0 | 2.0 |
Comparison — AISC Table J3.3 vs AS 4100 Table 9.6.2
| Bolt Size | Metric STD Hole | Metric Oversize | Short Slot (w × l) | Long Slot (w × l) |
|---|---|---|---|---|
| M16 | 18 mm | 20 mm | 18 × 22 mm | 18 × 40 mm |
| M20 | 22 mm | 24 mm | 22 × 26 mm | 22 × 50 mm |
| M24 | 26 mm | 30 mm | 26 × 32 mm | 26 × 60 mm |
| M27 | 30 mm | 34 mm | 30 × 37 mm | 30 × 67 mm |
| M30 | 33 mm | 38 mm | 33 × 40 mm | 33 × 75 mm |
| M36 | 39 mm | 44 mm | 39 × 46 mm | 39 × 90 mm |
Frequently Asked Questions
What is the standard hole size for a 3/4 inch A325 bolt per Table J3.3? A 3/4 in. bolt requires a standard (STD) hole of 13/16 in. diameter. The standard hole clearance is 1/16 in. For net area calculations, the hole deduction is 13/16 + 1/16 = 7/8 in.
When are oversized holes permitted? Oversized holes are permitted only in slip-critical connections, never in bearing-type connections. They require plate washers over any outer ply and carry a 15% slip resistance penalty (h_sc = 0.85).
What is the net area deduction for a bolt hole? The net area deduction = standard hole diameter + 1/16 in. For a 3/4 in. bolt: 13/16 + 1/16 = 7/8 in. The extra 1/16 in. accounts for material damage from punching.
What is the difference between short-slotted and long-slotted holes? SSL holes have slot length approximately d + 3/8 in. and are permitted in both bearing and slip-critical connections. LSL holes have slot length approximately 2.5d and are restricted to slip-critical connections only with plate washers required.
How do I choose which hole type to specify? Standard holes as default. Oversized holes for slip-critical connections with accumulated tolerances. Short-slotted for one-direction adjustment. Long-slotted for ongoing movement accommodation.
Run This Calculation
Use the Bolted Connections Calculator for automatic bolt shear, bearing, tearout, block shear, and hole type selection per AISC Table J3.3.
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Related Pages
- AISC Table J3.2 — Bolt Shear Strength
- AISC Table J3.4 — Minimum Edge Distance
- AISC Block Shear — Section J4.3
- Bolt Spacing & Edge Distance Reference
- Bolted Connections Calculator
Educational reference only. Verify against AISC 360-22 Table J3.3 and governing project specification.