Assessment of composite column and RC beam joints

Structural steel reinforced concrete (SRC) composite column to reinforced concrete (RC) beam connections are widely used in South Korea in the top-down construction method. Several joint types have been proposed and implemented for anchorage of the steel reinforcing bars. These anchoring methods can be classified as the passing through type, the wing plate type, and the H-beam bracket type. Their structural performance, however, is not yet clearly understood. In this paper, the experimental exploration of structural characteristics such as strength, stiffness, stiffness degradation, energy dissipation capacity and ductility under monotonic and cyclic loads is described. The test results show that the passing through type connection has the best structural performance of the joint types tested. However, in practice, it is inefficient to make holes in the thick flange of steel columns. With improvements to the passing through type, wide beam type joints were experimentally investigated in a practical application. In the wide beam type joint, the tensile force was resisted by a number of steel reinforcing bars placed at the edge of the slab without intersecting a steel column and without changing its cross-sectional shape. The wide beam type was found to be adequate in the SRC column to RC beam joint not only because of its structural capacity but also for its economic merits.