Section 25.5.1/Lap Splices of Deformed Bars in Tension
ACI 318-19 Section 25.5.1 covers lap splice requirements for deformed reinforcing bars in tension, directly affecting rebar scheduling and detailing.
Lap splices for deformed bars in tension must be either Class A or Class B. Class A splices have a length equal to the development length (ld). Class B splices have a length equal to 1.3 times ld. Class B is required when more than 50 percent of the bars are spliced within the required lap length, or when the area of reinforcement provided is less than twice the area required by analysis at the splice location. In practice, most field splices are Class B.
Why this section exists
Reinforcing bars are manufactured in standard lengths (typically 20, 40, or 60 feet) and must be spliced where longer continuous bars are needed. Lap splices transfer force from one bar to another through the surrounding concrete. The splice must be long enough for the full bar force to transfer. Where many bars are spliced at the same location, the increased demand on the surrounding concrete requires a longer splice length (Class B).
What plan reviewers look for
Plan reviewers check that lap splice lengths are specified on the structural details or in a splice schedule. They verify the splice class (A or B) based on the percentage of bars spliced and the reinforcement ratio at the splice location. They also check that splices are not located at points of maximum stress unless the reinforcement is significantly oversized.
Common violations
Related ACI 318 requirements
Section 25.4.2 covers the development length that forms the basis for splice length calculations. Section 25.5.2 covers lap splices in compression. Section 25.5.7 covers mechanical and welded splices as alternatives to lap splices.