The experimental study of the new pore-forming grouting connection joint with welded closure confinement steels

This paper describes a new designed precast shear wall structure connection joint in China, which can effectively reduce the production costs of connectors and significantly improve the construction speed. This connection joint is the new pore-forming grouting connection joint with welded closure confinement steels (NPGCS). This connection joints use the thin metal bellows to form the pores, by which can dramatically cut the construction price compared to the traditional steel sleeves connections, and reinforce more welded closure confinement steels to improve the mechanic properties of concrete and thus to realize the connection of vertical steel bars. The construction of the shear wall structures using NPGCS contains three processes including the pore forming in wall panels' production, the steel insertion and assembly in site, the steel bars grouting. Later, by the experimental test of two precast shear wall specimens using NPGCS and one cast-in-situ shear wall specimen which has the same parameters with the precast specimens, the performance of the connection joints were studied. The experimental results show that even with the existing of the grouting layer which can significantly week the mechanic properties of the vertical connection steel bars, the mechanic properties of the connection joint, including the capacity and ductility, are close or even better than those of the cast-in-situ specimen contributing to the reinforcement of the welded closure confinement steels. So, from the characteristics of the connection and the study results, it is obviously that the NPGCS has a wide application prospect in the building industrialization.