PROFIS ENGINEERING
Table 22. Interaction
Tri-Linear: N ua ϕN n
+ V ua ϕV n
≤ 1.2
0.54 + 0.57 = 1.11 < 1.2 OK
Parabolic: N 5 5
ua 3 V ua + 3 ≤ 1. 0 ϕN n ϕV n
ACI 318-19 Eq.( 17.8.3)
Reference ACI 318-19 commentary R17.8.
( 0.54) 5 / 3 +( 0.57) 5 / 3 = 0.358 + 0.392 = 0.75 < 1.0 OK FASTENING MEETS THE DESIGN CRITERIA.
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 row 1 and row 2 is less than c a1, row 1
• ACI 318 Case 3 provisions are relevant for row 1 and row 2.
• Calculate concrete breakout( ϕV cbg) from row 1 using c a1, row 1.
• Assume 1.0V ua acts on row 1( conservative assumption) neglects load on row 3
• Check ϕV cbg, row 1 vs. 1.0V ua
• y direction anchor spacing in between row 2 and row 3 is greater than c a1, row 1
• ACI 318 Case 1 / Case 2 provisions are relevant for row 1 and row 3.
• Calculate concrete breakout( ϕV cbg) from row 3 using c a1, row 3.
• Calculate concrete breakout( ϕV cbg) from row 1 using c a1, row 1.
• Assume V ua is distributed between row 1 and row 3
• Check ϕV cbg, row 3 vs. 1.0V ua
• Check ϕV cbg, row 1 vs. 0.5V ua
•( N ua / ϕN cbg) controls the design with respect to 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 Unequal Spacing( page 10) in the design guide.
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