Appendix B - Development and Lap Lengths

Lap Splice Lengths(1) and Hooked Bar Embedments (inches)

(1) Min. lap for spliced bars, in., assumes fy = 60 ksi, per ACI 318-11, Equation (12-1).

(2) 40 bar diameters for fy = 40 ksi and 48 diameters for fy = 60 ksi IBC ’12-2107.2

(3) Min. lap is development length x 1.3, assuming Class B splice. Cannot be reduced for stress level.

(4) Assumes standard hook and not reduced by ratio As (required) / As (provided).

Note that IBC ’12, 2107.2, modifies ACI 530-11, Section 2.1.7.7.1.1 which has the effect of deleting the following

development length equation in ACI 530:

γ = 1.0 for #3, #4, #5 bars, 1.4 for #6, #7, and 1.5 for #8

K = Masonry cover but not less than 5 db

This requirement resulted in much longer lap lengths and has met with considerable objection.