Free Engineering Tool #223

Anchor Bolt Pullout Calculator

Calculate anchor bolt pullout capacity per ACI 318. Enter bolt diameter, embedment depth and concrete strength.

ACI 318Pullout CapacityConcrete Anchors

Results

Concrete Breakout Capacity

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Breakout Cone Area

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Effective Depth

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Where k_c=24 for cast-in anchors, h_ef is effective embedment, and f’_c is concrete compressive strength.

A 35° cone from the anchor head to the concrete surface. The projected area determines the capacity.

Distance from concrete surface to the bearing surface of the anchor (head or nut).

Capacity is proportional to √fc. Doubling fc increases capacity by ~41%.

Reduced edge distance requires capacity reduction factors per ACI 318.

Cast-in anchors use kc=24. Post-installed may use kc=17 depending on type and approval.