Design guide for considering concrete breakout in shear using ACI 318 anchoring-to-concrete provisions October 2025 | Page 91

PROFIS ENGINEERING

SUMMARY

•

Consider shear concrete breakout for anchor rows 1, 2 and 3.

• PROFIS Engineering considers a maximum of three anchor rows / columns with respect to shear concrete breakout calculations.

• Assume shear load acts towards the y- edge.

• x direction anchor spacing in each row is less than 3c a1, row 1

• Anchors in each row act as a group.

• y direction anchor spacing in between each row is greater than c a1, row 1

• ACI 318 Case 1 / Case 2 provisions are relevant.

• Calculate concrete breakout towards y- edge from row 1, row 2 and row 3

• Calculate ϕV cbg, row 1 using c a1, row 1 and check vs. 0.33V ua

• Calculate ϕV cbg, row 2 using c a1, row 2 and check vs. 0.67V ua

• Calculate ϕV cbg, row 3 using c a1, row 3 and check vs. 1.0V ua

•( 1.0V ua / ϕV cbg, row 3) controls the design with respect to concrete breakout in shear

•( 1.0V ua / ϕV cbg, row 3) controls the design with respect to all shear failure modes

•( N ua / ϕN cbg) controls the design with respect to all tension failure modes

• Tension / shear interaction is satisfied: fastening satisfies ACI 318-19 provisions.

For more information on extrapolating ACI 318 shear concrete breakout provisions with respect to this design example, reference Equal Number of Anchors and Equal Spacing – Case 3( page 8) in the design guide.

One Fixed Edge- V ua Towards Edge – Case 1, Case 2 and Case 3

carbon steel: f ult = 75,000 psi f y = 55,000 psi

Sustained Tension: N ua = 16,000 lb h ef = 10.0 in

October 2025 91