The Study of The Behavior and Punching Shear Strength of The Joint System between Concrete Slabs and Hollow Structural Steel Columns

Abstract

Researchers from Sahaviriya Steel Industries PCL. Or SSI, initiated the innovative construction system using hollow steel sections as gravity columns with the splicing joints that are capable of supporting while being embedded in the reinforced concrete floor, commercially called “PostConnex”. The research was performed via laboratory testing with 2 samples per 1 testing condition of the fabricated steel PostConnex system being cast in reinforced concrete slab, for which testing conditions varied (1) shear headed stud, (2) connection cap-plate and stiffener-assemblage thicknesses, (3) bolt diameter and (4) cap plate yield strength, in order to investigate punching shear capacity and to observe system behavior in comparison with punching shear capacity as per ACI 318-19, as well as Critical Shear Crack Theory, CSCT. The results showed that the testing conditions either with or without shear headed studs were higher than calculated value per the above-mentioned standard for approximately 42% and 28% consecutively, while in line with Critical Shear Crack Theory. This can be concluded that PostConnex can be safely designed in accordance with the current design standard and CSCT with the alignment of the assumed behavior of connecting components. Hence, PostConnex can be practically used for the gravity column application for multi-story buildings.