Numerical analysis of the cyclic behavior of the fully connected reinforced concrete shear wall to concrete-filled tube columns

Concrete-filled tube (CFT) columns are often used in composite frame structures due to their remarkable characteristics. However, the lateral performance of CFT columns in frame structures is found to be inadequate and thus, reinforced concrete shear walls are often incorporated into such frames. The interaction between reinforced concrete shear walls and CFT columns relies primarily on shear studs, while shear studs can create composite action between the wall and CFT columns, their capacity is not fully utilized under cyclic loads. Therefore, this study proposes a new type of connection for reinforced concrete shear wall with CFT columns. The proposed connection consists of shear studs and welded horizontal reinforcements of the reinforced shear wall directly on CFT columns, which is called a full connection. To evaluate the effectiveness of the proposed connection, a three-dimensional (3D) six-story frame building was designed using ETABS. Subsequently, a subframe of the six-story building was then selected for numerical analysis using LS-DYNA finite element software, considering two types of connections, a partial connection and a full connection. The numerical study comparing the frames with partial and full connections, considering different diameters of shear studs, is conducted through quasistatic cyclic analysis to assess their cyclic responses. The results in terms of crack pattern, force–displacement hysteresis curves, effective stiffness, and damping ratio are discussed in detail. The cyclic responses of the full connection frames are found to outperform the frames with the partial connection. In conclusion, the proposed connection facilitates a smoother load transfer path between the concrete of the shear wall and the CFT columns and provides a better composite action between them.