Bar | |||
d_{b} | 0.375 | in | bar diameter. |
λ | |||
f'_{c} | psi | Specified 28-day compressive strength of concrete in which the bar is to be developed. | |
f_{y} | Yield strength of bar to be developed. |
↑ ACI 318-19 Straight Tension Development Length, L_{d}:
Ψ_{t} | More than 12 in. of fresh concrete placed below horizontal reinforcement. | ||
Ψ_{e} | Epoxy-coated or zinc and epoxy dual-coated reinforcement with clear cover less than 3d_{b} or clear spacing less than 6d_{b}. | ||
Ψ_{s} | No. 6 and smaller bars and deformed wires | ||
Ψ_{g} | Grade 40 or Grade 60 | ||
c_{c} | in | distance from center of bar to nearest concrete surface. | |
s_{b} | in | center-to-center spacing of bars being developed. | |
c_{b} | 1.5 | in | |
A_{tr} | in^{2} | Total cross-sectional area of all transverse reinforcement within spacing s that crosses the potential plane of splitting through the reinforcement being developed. If unsure of value use 0. | |
s | in | maximum center-to-center spacing of transverse reinforcement within L_{d}. | |
n | number of bars being developed. | ||
K_{tr} | 0 |
\[L_{d} = \text{max } \begin{bmatrix}\text{(a) }\left( \frac{3}{40} \frac{f_{y}}{\lambda\sqrt{f'_{c}}} \frac{\psi_{t}\psi_{e}\psi_{s}\psi_{g}}{(\frac{c_{b}+K_{tr}}{d_{b}})} \right) d_{b} \text{ (25.4.2.4a)} \\ \text{(b) }12 \text{ in} \end{bmatrix} \text{[25.4.2.1]}\] | ||
\[K_{tr} = 0.0 \] | ||
↑ ACI 318-19 Hooked Development Length, L_{dh}:
Ψ_{e} | Epoxy-coated or zinc and epoxy dual-coated reinforcement | |
Ψ_{r} | Other | |
Ψ_{o} | Other | |
Ψ_{c} | test |
\[L_{dh} = \text{max }\begin{bmatrix}\text{(a) } \left(\frac{f_{y}\psi_{e}\psi_{r}\psi_{o}\psi_{c}}{55\lambda\sqrt{f'_{c}}} \right)d_{b}^{1.5} \\ \text{(b) }8d_{b} \\ \text{(c) }6 \text{ in} \end{bmatrix} \text{ [25.4.3.1]} \] | ||