Seismic Performance of a Novel Partially Embedded Transfer Connection with Wing Wall in Steel-Concrete Vertical Irregular Structures: Physical Tests and Theoretical Model

The design of transfer connections in steel-concrete vertical irregular structures is crucial for high-rise buildings and long-span structures due to the abrupt changes in mass, stiffness, and damping ratio. The conventional approach is to embed all the upper steel columns into the lower reinforced concrete (RC) to form steel-reinforced concrete columns (SRCs), resulting in high steel consumption associated with significantly increased construction costs. To address this issue, a novel solution of a partially embedded transfer connection with a wing wall (PETC-WW) is proposed in this paper. The proposed PETC-WWs in four types together with a conventional approach, i.e., deeply embedded connection (DEC), were designed and constructed to undergo large-scale physical tests. The tests were conducted by a combination of cyclic lateral loading and preaxial compressive loading. The seismic performance of these transfer connections was then evaluated. The test results indicate that all four types of the proposed PETC-WW have better performance than the DEC in terms of higher load-carrying capacity, greater structural stiffness, and better energy dissipation. It was found that the presence of the wing wall can effectively prevent premature failure of the central RC column, thereby reducing the risk of collapse of the upper structure. In addition, a theoretical model for the proposed PETC-WW was developed. The strengths predicted by the theoretical model were compared with the corresponding test strengths. The differences between the theoretical predictions and test results were within 10%. The proposed PETC-WW is superior to the conventional approach in cost and convenience of construction, as well as effectiveness in seismic resistance. It is hence recommended to be adopted in steel-concrete vertical irregular structures in high-intensity seismic areas.