How to use this calculator
- Enter anchor geometry. Use the anchor diameter and effective bonded embedment depth.
- Set the design load. Enter the target tension load being screened.
- Enter material values. Use the bond stress and steel allowable stress from your source, then choose a safety factor.
- Read the governing capacity. Compare bond capacity, steel capacity, utilization and required embedment.
- Verify final design separately. Check code, manufacturer, edge, spacing, cracked concrete and installation requirements before use.
How it works
This epoxy anchor pullout calculator uses a cylindrical bond screen. The bonded area is the anchor perimeter times the effective embedment:
A_bond = pi x d x h
T_bond = A_bond x tau_b / SF
It also calculates the gross steel tensile area and compares the entered steel stress limit against the same safety factor:
A_s = pi x d^2 / 4
T_steel = A_s x sigma_s / SF
The governing tension capacity is the lower of the bond and steel design capacities. Required embedment is back-solved from the target tension and entered bond stress.
Worked example
Verified against the live calculator
A 1/2 in adhesive anchor with 4 in effective
embedment, 1000 psi entered bond stress, 36 ksi
entered steel stress and SF = 3 gives about
2,090 lbf bond design capacity and
2,360 lbf steel design capacity. Bond governs. A
1,500 lbf target tension is about 72%
utilization, and the bond-only required embedment is about
2.9 in.
Frequently asked questions
How do you calculate epoxy anchor pullout?
For a bond-only screen, multiply the bonded surface area by the entered bond stress: T = pi*d*h*tau. Divide by the entered safety factor, then compare that bond capacity with the steel tensile capacity.
Does this replace ACI or the anchor manufacturer tables?
No. This is a formula-only screening calculator. Final adhesive anchor design still needs the approved manufacturer data, adopted code, concrete condition, installation requirements and engineering review where required.
Does it include concrete breakout, edge distance or anchor groups?
No. It reports edge distance as context only. Concrete breakout, pryout, cracked concrete, close edges, anchor spacing and group interaction can govern real anchors and are outside this calculator.
What bond stress should I enter?
Use the allowable or nominal bond stress from the adhesive manufacturer, project criteria, pull-test data or a conservative engineering assumption for the actual substrate, hole condition, temperature and installation method.
Method & assumptions
- Uses the entered bond stress and steel allowable stress. No anchor product table, ESR, ETA, ACI or local-code table is embedded.
- Bond capacity is
pi*d*h*tau_b/SF. Steel capacity is(pi*d^2/4)*sigma_s/SF. - Nearest edge distance is only a context ratio. Concrete breakout, pryout, spacing, groups and edge reductions are not calculated.
- Cracked concrete, seismic requirements, sustained loads, hole cleaning, adhesive cure, wet holes, temperature and inspection are outside this screen.
- Use rebar spacing, rebar lap splice length, deck footing concrete and bolt shear strength tools for adjacent takeoff and fastener checks.