Design guide for considering concrete breakout in shear using ACI 318 anchoring-to-concrete provisions October 2025 | Page 74

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Nominal Bond Strength in Tension( N ag)

N ag =

A Na A Na0 ψ ec, Na ψ ed, Na ψ cp, Na N ba ACI 318-19 Eq.( 17.6.5.1b)

c Na = 10d a τ uncr 1100

design τ k, uncr =( ESR τ k, uncr)( f ' c / 2500 psi) 0. 25 =( 2040 psi)( 4500 psi / 2500 psi) 0. 25 = 2363 psi c Na =( 10)( 0.875 in)( 2363 psi / 1100 psi) 0. 5

ACI 318-19 Eq.( 17.6.5.1.2b) Reference ESR-3814 Table 11 for τ k, uncr and() xx. ESR τ k, uncr = 2040 psi d a = 0.875 in() xx = 0.25 f’ c = 4500 psi

= 12.83 in

A Na =( c x- + s x1 + s x2 + s x3 + c x +)( c y- + s y12 + s y23 + s x34 + c y +) =( 12.83 + 9.0 + 9.0 + 9.0 + 12.83)( 6.0 + 8.0 + 8.0 + 8.0 + 12.83) = 2255 in 2

A Na0 =( 2c Na) 2

c y + = ∞ in = c Na ψ ec, Na =

=( 25.66 in) 2 = 658.44 in 2

1 1 + e ′ N c Na

= 1.0 no eccentricity

ψ ed, Na = 0.7 + 0.3 c a, min c Na c Na = 12.83 in

2c Na = 25.66 in

ACI 318-19 Eq.( 17.6.5.3.1)

e’ N = 0.0 in c Na = 12.83 in

Reference ACI 318-19 Eq.( 17.6.5.4.1b)

= 0.7 +( 0.3)( 6.0 in / 12.83 in) = 0.84 c a, min = c y- = 6.0 in c Na = 12.83 in ψ cp, Na = MAX c a, min

| c Na c ac c ac

= 1.0 cracked concrete

Reference ACI 318-19 Eq.( 17.6.5.5.1b)

N ba = λ a α N, seis τ xxxx π d a h e f

ACI 318-19 Eq.( 17.6.5.2.1)

Reference ESR-3814 Table 11 for α N, seis. normal weight concrete: λ = 1.0 → λ a = 1.0 ACI 318-19 Table 17.2.4.1 design τ k, cr =( ESR τ k, cr)( f ' c / 2500 psi) 0. 15 =( 1240 psi)( 4500 psi / 2500 psi) 0. 15 = 1354 psi N ba =( 1.0)( 1.0)( 1354 psi)( π)( 0.875 in)( 12.0 in) = 44,664 lb

Reference ESR-3814 Table 11 for τ k, cr and() xx. ESR τ k, cr = 1240 psi f ' c = 4500 psi() xx = 0.15

d a = 0.875 in α N, seis = 1.0 h ef = 12.0 in

N ag =

A Na A Na0 ψ ec, Na ψ ed, Na ψ cp, Na N ba

N ag =( 2255 in 2 / 658.44 in 2)( 1.0)( 0.84)( 1.0)( 44,664 lb) = 128,489 lb

A Na = 2255 in 2 A Na0 = 658.44 in 2 ψ ec, Na = 1.0 ψ ed, Na = 0.84 ψ cp, Na = 1.0 N ba = 44,664 lb

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