STRENGTHENING EXISTING SLAB-COLUMN CONNECTION USING CFRP STRIPS IN HYBRID WITH STEEL COLLAR

Abstract

A variety of factors such as a change in the building's usage, the necessity to install new services, the corrosion of reinforcement, and construction or design mistakes, might make the punching shear strength of an existing slab-column connection crucial. Existing slab-column connections may need to be strengthened throughout the service life of a structure to address these problems. Different strengthening methods have been described by certain researchers, such as inserting shear reinforcements beforehand or afterward, providing transverse reinforcement bars, raising the column head, and enveloping the slab in fiber-reinforced polymer (FRP) sheets close to the shear critical zone. The performance of the existing slab-column connection, strengthened with CFRP strips in hybrid with steel collar at the inner slab-column connection, was analytically examined in this work to prevent future degradation of the degraded slab. The commercially accessible finite element software ABAQUS version 6.14-2 was used for modeling, analysis, and result generation. By comparing the software data to experimental data from the literature, which showed good agreement, the software data were validated. The CFRP strip length, CFRP strip width, CFRP end anchorages, dimensions of the steel plate, and its thickness are the primary study parameters that were examined. These materials' effects are investigated in terms of structural response parameters such as yield and ultimate load-carrying capacity, ductility, stiffness, energy absorption, and specimen failure mechanisms. Utilizing the hybrid strengthening technique resulted in improvements to several of the metrics examined with the structural performance of the tested specimens. The technique with increased CFRP length showed a stronger influence on enhancing ultimate load, ductility, and energy absorption capacity as compared to the control specimen. 37.17%, 61.61%, and 75.44%, respectively, were the increases. The control slab's ductile Punching failure mode has been altered to a flexural failure mode as a result of the strengthening procedure. Simple bolt holes can be drilled through steel collars and columns for bolt installation, but the column size needs to be large enough to permit connecting bolt holes that need to be drilled transversely through the column section.