An experimental study on structural resistance of square CFT column to beam connections using internal plate with holes

As the height of recently-constructed buildings increases, new structure system is applied in addition to existing S, RC and SRC to reduce building weight and to secure construction efficiency. In particular, a CFT structure has been applied to many building construction cases due to its superior structure performance and constructability. The CFT structure requires a diaphragm to facilitate the smooth transfer of the beam flange load to the column and the opposite beam in connections. In particular, when a beam with a different depth is connected to the right and left sides of the column in building construction case, there appeared to have been difficulty in establishing a diaphragm designed for smooth transfer of the lower-part flange load delivery of the beam and in ensuring concrete filling capacity. This paper proposes connection details of forms that vertically welded a perforated plate to the inside of a CFT column to smoothly transfer lower-part beam flange load to the column. This connection method uses the anchor effect of concrete in delivering the beam flange load, by filling holes of an internal perforated plate with concrete when the inside of the CFT column was filled with concrete. Moreover, the vertical installation of the perforated plate enhanced a concrete filling capacity. To analyze the structural performance of the proposed connection details, five specimens were made with parameters that corresponded to the installment direction of the perforated plate (vertical and horizontal), whether or not there was concrete filling, the thickness of the perforated plate, and the number of shear holes. Experimental tests were also conducted on the specimens.