A307 Anchor Bolt ((top)) [ 90% RECENT ]
| Error | Correction | | :--- | :--- | | Specifying "A307 anchor bolt" without grade | Write: ASTM A307, Grade A, low-carbon steel, plain finish, 36 ksi min yield, 60 ksi min tensile. | | Using A307 in epoxy anchors | Specify F1554 Grade 36 or 55 for adhesive anchoring. | | Omitting bend radius for L-bolts | Minimum inside bend radius = 2 × bolt diameter. | | No corrosion allowance | Add: Hot-dip galvanize per ASTM A153, unless noted otherwise. |
| Environment | Required Protection | | :--- | :--- | | | As-rolled (plain) acceptable | | Exterior, moderate | Hot-dip galvanized per ASTM A153 (minimum 2.0 oz/ft²) | | Coastal/marine | Stainless steel (Type 304 or 316) – A307 spec does not apply; use F1554 | | Embedded in concrete | No coating required (alkaline passivation) – but cutoff must be above ground | a307 anchor bolt
| Property | Value | | :--- | :--- | | | 60 ksi (414 MPa) minimum | | Yield Strength | 36 ksi (248 MPa) minimum (typical, not mandatory by ASTM but implied by material) | | Elongation | 18% minimum (in 8 in.) – High ductility | | Hardness | Brinell 100–241 | | Threads | UNC series (Class 1A or 2A) | | Material | Low-carbon steel (e.g., A36, 1018) | | Error | Correction | | :--- |
The ASTM A307 anchor bolt is not a “lesser” product—it is an product for specific roles. Its high ductility (18% elongation) exceeds that of higher-strength bolts, making it valuable for connections requiring plastic deformation without fracture. However, engineers must resist the temptation to “upgrade” to A307 for simplicity. For seismic, high-tension, or cyclic loading, F1554 Grade 55 or Grade 105 is required. When used correctly—embedded in concrete for light structural or non-structural anchorage—the A307 bolt provides safe, reliable, and economical service for decades. | | No corrosion allowance | Add: Hot-dip
Performance, Limitations, and Specification of ASTM A307 Anchor Bolts in Structural Applications
| Prohibited or Dangerous Application | Reason | | :--- | :--- | | in seismic zones (D, E, F) | Lack of guaranteed strain-hardening capacity and impact toughness. | | High-tension bracing connections (e.g., tension-only braced frames) | Steel tensile failure may occur before concrete breakout, leading to brittle collapse. | | Epoxy-grouted or adhesive anchors under sustained tension | A307 bolts have no surface treatment spec; smooth surface reduces bond strength. Adhesive manufacturers often require F1554. | | Shear lugs with tension (combined loading >20% of capacity) | Low shear strength relative to higher-grade bolts. | | Post-installed anchors in overhead life-safety applications | IBC prohibits unless specifically tested per ACI 355.2. A307 rarely qualifies. |
A307 anchor bolts are ideal for where ductility and economy are priorities, but ultra-high strength is not required.