Appendix B - Development and Lap Lengths

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.