One method to establish the continuity between precast components is splicing reinforcing bars from components that need to be connected. To complete this process, the coupler is required to splice two bars together. It allows axial force to be transferred from one bar to the other. Several styles of bar splicing system are commercially available. Following describes the most common rebar couplers that are classified by mechanical principle.x

• Threaded sleeve
  The bars are manufacturedwith male thread with or without taper, and they screw into a sleeve with a female thread.
• Screw lock sleeve
  A steel sleeve fits over the bar. Set screws are driven through the sleeve into the bar and clamp the bar.
• Filler sleeve
  A steel sleeve fits over the bar and is filled with metal or grout.
• Headed bar sleeve
  A head is formed on the end of each bar and a threaded coupling piece draws the two together.
• Grip sleeve
  A steel sleeve is swaged onto the bar ends by a hydraulic tool.
• Side-by-side mechanical lap splice
  A steel sleeve is positioned around two overlapping bars, and a wedge pin is driven into a hole between two bars. Some products utilize set screws clamp the bars.

For some products, two mechanical principles are combined together. Following table provides a brief summary on the features of each splicing system.

Reinforcement end anchorage systems are designed to minimize embedment length and develop the tensile strength of the bar. The end anchorage can be prefabricated at the end of plain rebar or be installed at field by several mechanical principles, including threaded sleeve, screw lock sleeve, and grip sleeve. End anchorages simplify the rebar splicing in areas where rebar congestion prevents use of long lap splices or large diameter hooked rebar.