ACI 439.3R-07

Reinforcing bar splices are key components in reinforced concrete construction. Because mechanical splices do not rely on the surrounding concrete to transfer the force between bars, splitting failures are not a concern, and the strength of the splice is not sensitive to the compressive strength of the concrete or the amount of cover. Splices in reinforcing steel are grouped in three categories: lapped bars, mechanical, or welded; the focus of this report is mechanical splices. Strength capacities established in ACI 318 are higher for mechanical splices than for lap splices. Several types of mechanical splices have been qualified to sustain inelastic reinforcing bar strain excursions representative of those that might be brought about by overload due to seismic activity, wind, or blast.

This report provides engineers and contractors with updated information about bar-to-bar mechanical splices and the types of proprietary mechanical splices currently available. There is no attempt to state conditions of acceptance or to endorse or rate one particular mechanical splice over another.

The information on mechanical splices and their installation was provided by mechanical splice manufacturers. Although it was compiled by the committee, none of the information was directly verified by the committee. An attempt was made to include generic descriptions of all types of mechanical splices generally available and sold in the North American market at the beginning of 2004; however, some mechanical splices new in the market may not be included due to lack of knowledge of their existence or because no information was submitted for inclusion at the time this report was written.

Reasons for using mechanical splices, as well as various engineering considerations that should be made when specifying mechanical splices, are discussed. Mechanical splices are described in terms of seismic type, configuration, installation procedure, clearance requirements, and other characteristics. Illustrations of the various mechanical splices are included.