Improvement of bearing performance on exterior steel beam-reinforced concrete column joints with steel column

To improve the bearing failure behavior of the exterior steel beam-reinforced concrete column joints composed of reinforced concrete columns, joint details using steel column was proposed. Steel column was attached to the lower flanges at right angles to the steel flange. The objective of this study is to clarify the effectiveness of proposed joint details experimentally and theoretically. To clarify the influence of steel column on the bearing failure of the joint, seven T-shaped subassemblages were tested under reversed cyclic loading. All specimens had the same cross sections of the steel beam. The experimental variables were the embedded length of the steel column, whether there is the end plate at the tip of the embedded steel column, and, the arrangement of transverse reinforcement ratio surrounding the steel column. The following remarks can be drawn from the test results. 1) In case of the specimen with a short embedded length of the steel column, the punching shear failure on the upper surface of the steel beam flange was remarkable when the maximum strength was reached. However, in the specimen with long embedded length of steel column, it was not observed the punching shear failure. 2) The maximum strength increased with the embedded length of the steel column. Further, the maximum strength of the specimen with the embedded length of three times of the steel column depths is subjected to bending yield strength of the steel column. 3) It was shown that the transverse reinforcement to surround the steel column and the end plate were necessary to improve the bearing failure of the joint.