Numerical investigation of the effect of joint core details on the performance of reinforced concrete column to steel beam connection in corner columns

The past severe earthquakes around the world have shown that the beam to column connection is prone to failure. Therefore, significant provisions should be considered in the design of the connection. RCS moment-resisting frame systems, consisting of Reinforced Concrete (RC) columns and Steel (S) beams, take advantage of the inherent stiffness and damping, as well as low-cost of concrete, the lightweight and construction efficiency of structural steel. Since two types of materials including steel and concrete are used in a RCS system, the detail of the connection plays a significant role on the overall performance of the system. In general, there are two types of RCS connections, column through type & beam through type. The main objective of this study is to investigate the effect of parallel and diagonal stiffeners on stress-strain propagation and concrete damage in column through type RCS connections. For this purpose, RCS connections with different joint details were modeled and analyzed in ABAQUS. Finite element analyses results showed that parallel stiffeners are more capable to provide confinement in comparison to the diagonal types. However, the performance of diagonal stiffeners in terms of strength and plastic hinge formation in the joint is better than parallel stiffeners. Increase of stiffener thickness causes to improve the performance of joint core and decreases its damage level. Furthermore, increasing in cover-plate thickness improves the performance of connections in terms of of strength and plastic hinge formation.