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Compression development length: validation

Every formula and clause of Compression development length was compared by hand with CSA A23.3-24, and every row matched, on 2026-10-01. The rows below are read from the calculation itself at its declared values, so they are the formulas the page runs today.

Formulas

NameSymbolicClauseAgainstDate
d_b\(\displaystyle 16\ \mathrm{mm}\)CSA metric bar sizes, nominal diameter2026-10-01
k_c\(\displaystyle 1\)CSA A23.3-24 Table 12.3, coating2026-10-01
k_d\(\displaystyle 1\)CSA A23.3-24 Table 12.3, concrete density2026-10-01
K_tr\(\displaystyle \frac{40 \cdot A_{\mathrm{tr}}}{s \cdot n}\)Cl. 12.3.2CSA A23.3-24 Cl. 12.3.2, K_tr and the 12 d_b spacing limit2026-10-01
l_dc\(\displaystyle \left(\frac{k_{c} \cdot k_{d} \cdot f_{y}}{1.3 \cdot \left(1 + \frac{0.1 \cdot \min\left(K_{\mathrm{tr}}, 1.75 \cdot d_{b}\right)}{d_{b}}\right) \cdot \min\left(\sqrt{f_{c} \cdot 1\ \mathrm{MPa}}, 8\ \mathrm{MPa}\right)} - 21\right) \cdot d_{b}\)Cl. 12.3.2, with the 8 MPa cap of Cl. 12.1.2CSA A23.3-24 Cl. 12.3.2 and Cl. 12.1.22026-10-01
l_d_single\(\displaystyle \max\left(l_{\mathrm{dc}} \cdot A_{s,\mathrm{ratio}}, 300\ \mathrm{mm}\right)\)Cl. 12.3.1 and 12.3.4CSA A23.3-24 Cl. 12.3.1 and Cl. 12.3.42026-10-01
k_bundle\(\displaystyle 1\)CSA A23.3-24 Cl. 12.3.52026-10-01
l_d\(\displaystyle l_{d,\mathrm{single}} \cdot k_{\mathrm{bundle}}\)Cl. 12.3.5CSA A23.3-24 Cl. 12.3.52026-10-01

Clauses

ClauseStepsAgainstDate
Cl. 12.3.2K_trCSA A23.3-24 Clause 12, as cited2026-10-01
Cl. 12.3.2, with the 8 MPa cap of Cl. 12.1.2l_dcCSA A23.3-24 Clause 12, as cited2026-10-01
Cl. 12.3.1 and 12.3.4l_d_singleCSA A23.3-24 Clause 12, as cited2026-10-01
Cl. 12.3.5l_dCSA A23.3-24 Clause 12, as cited2026-10-01