The precast construction method is effective for improving the quality of reinforced concrete structures and rationalizing the construction, so applications have continued to increase. This method is an important factor in the joining between the PC members, especially the joint design and construction of the reinforcing bars.

Rebar coupling method have been developed and applied to various types of couplers such as lap coupler, gas pressure welding coupler, mechanical coupler, and welded coupler. Among them, grout-charging coupler method is often adopted for it’s ability to absorb the error of the reinforcing bars to facilitate construction and suitability for large-diameter reinforcing bars which are widely used recently.

High strength is required for concrete and rebars as well in designing rebar and concrete members, due to size of buildings has become larger and taller. The BCS splice sleeve suitable for SD600 high-strength steel bars was actually developed for reinforcing bars, and its structural performance is evaluated and put into practical use. After completion of development of SD600 high strength rebar compatible splice sleeve, it has been widely used as a reinforcing material for column members for places such as underground parking lots, parking buildings, apartment basements and warehouses. D16, D19, D22, D25, D29, D32, and D35 have been developed and commonly used after extensive testing.