AN INNOVATIVE DETAIL FOR PRECAST CONCRETE BEAM COLUMN MOMENT CONNECTIONS

A new detail is introduced for precast concrete beam-to-column moment connections. The detail consists of a connecting steel frame used to mechanically connect the threaded end protruding reinforcing bars from beam and column. The connection detail is made convenient to assemble where the erection method resembles that of steel construction. No idle crane time is necessary, since the connecting steel frame is designed to carry the beam's own weight. When the connection construction is completed, the joint functions as a moment resisting hard connection. The experimental testing program involved testing of twelve full-scale specimens in addition to a pilot test. Of the twelve tests seven are flexural tests, three are shear tests, and two are monolithic flexural tests for comparison. Modes of failure in the flexural tests were mainly due to rupture of tension reinforcement; however, premature slippage of the rebars may occur under certain conditions, but could be conveniently prevented. In the shear tests, diagonal tension crack failure predominated. If the connection parameters are properly selected, the connection will be capable of developing the beam's full plastic moment and undergo sufficient rotation before collapse.