Anchor Bolt Design

Quick pick (TL;DR)

Cast-in headed studs for new foundations & high load; chemical (adhesive) anchors for retrofit; expansion anchors only for light/temporary duty.
Find the tension per bolt from the overturning moment (couple), check the bolt steel (φNsa), then check the concrete failure modes to ACI 318 Chapter 17 — breakout, pullout, pryout and edge — which usually govern and drive embedment depth & edge distance.

Step 1 — Anchor type

Type	Use for	Note
Cast-in stud	New / heavy	Strongest
Chemical	Retrofit	Cure-dependent
Expansion	Light duty	Limited

Step 2 — Worked tension check

Vessel base, M 40 kN·m, 4 bolts

Given overturning moment M = 40 kN·m 4 bolts, tension-side lever arm s = 0.5 m Step 1 — Tension per bolt 2 bolts resist on the tension side T = M / (s × n) = 40 / (0.5 × 2) T = 40 kN/bolt Step 2 — Steel capacity φNsa = φ · As · fut (M16, As 157 mm²) φNsa = 0.75 × 157 × 400 = 47,100 N φNsa = 47.1 kN Step 3 — Check T / φNsa = 40 / 47.1 = 0.85 → steel OK Then — concrete → check breakout/pullout; set hef & edge

Moment → tension couple; steel is easy — ACI 318 concrete breakout usually governs hef & edge distance.

Step 3 — Concrete & detailing

Concrete breakout governs — hef/edge/rebar.
Check shear & tension-shear interaction.
Sleeves for adjustment; ductile if seismic.

Anchor tension calculator

Tension per bolt & steel check

T = M/(s·n_t); φNsa = φ·As·fut. Concrete breakout usually governs.

Moment M (kN·m)

Lever arm s (m)

Tension-side bolts

Bolt size

fut (MPa)

Steel check only — ACI 318 Ch.17 concrete checks usually govern embedment/edge.

Common mistakes

Ignoring concrete breakout.
Expansion anchors on vibration.
Edge distance too small.

Requisition & datasheet

Application, loads, bolts.
Type, size, capacity, concrete checks.

Frequently asked questions

What should I know about Anchor Bolt Design?

Cast-in headed studs for new foundations & high load; chemical (adhesive) anchors for retrofit; expansion anchors only for light/temporary duty. Find the tension per bolt from the overturning moment (couple), check the bolt steel (φNsa), then check the concrete failure modes to ACI 318 Chapter 17 — breakout, pullout, pryout and edge — which usually govern and drive embedment depth & edge distance.

Which standards or codes apply?

ACI 318 Chapter 17 (anchoring to concrete), ACI 349 (nuclear/heavy), AISC Design Guide 1 (base plates & anchor rods), ETAG/EOTA for post-installed anchors.

Standards — ACI 318 Ch.17; ACI 349; AISC DG1; ETAG.