Towards deformation-based capacity design of RCS beam–column connections

Hybrid RCS frame systems consisting of reinforced concrete (RC) columns and steel (S) beams have been recognized to possess several advantages in terms of structural performance and economy compared to pure RC and steel frames. However, their use has been limited to low or moderate seismic regions due to lack of appropriate design guidelines for RCS frames in high seismic risk zones. In this article, the implementation of a deformation-based capacity approach for the design of RCS connections in frames located in high seismic risk zones is described. The main purpose of the design procedure is to control joint distortions and damage, forcing most of the frame inelastic activity to occur in the beams. The design procedure is validated through the testing of two RCS beam–column–slab subassemblies under displacement reversals. Experimental results indicate that the proposed design procedure is effective in controlling joint deformations and damage, leading to the formation of plastic hinges at the beam ends. The test specimens showed excellent seismic behavior with significant energy dissipation capacity, which demonstrates the suitability of RCS frames for use in high seismic risk zones.