Reinforcing bars (rebars) come in lengths of up to 60 feet. Theoretically speaking, this seems to obviate the need for splicing the rebars for all but the largest commercial projects. In practice, however, most building projects involve extensive rebar splicing. Due to many reasons, such as shipping constraints on the length and efficient use of materials. A lap splice is the most common method of creating a single structural entity from two rebar segments.

The lap splice, as the name suggests, is created by overlapping two lengths of rebar, then wiring them together. From a structural point of view, the most critical aspect of a lap splice is the overlap length. Note, however, that overlap requirements vary with both rebar size and the specific structural application.

Rebar Lap Splice Model Codes

In almost every construction situation, overlap lengths are subject to local building codes. Although it's imperative to check your local code for detailed compliance requirements, most codes are based on the International Building Code (IBC).

IBC code requirements are almost identical to the American Concrete Institute (ACI) codes. ACI code section 318-14, which governs rebar splicing, has been incorporated without meaningful modification into the corresponding concrete section of the 2015 and 2018 IBC. Therefore, either the IBC code sections governing concrete or ACI 318-14, current as of 2016, provide reliable information about lap splice code requirements.