Strengthening of interior circular column-slab region incorporating combinations of bonded UHPECC layer, CFRP sheets, and threaded steel bolts
Ahmed Hamoda, Khaled Sennah, Aref A. Abadel, Mohamed Emara
Abstract
This study aims to address safety concerns related to punching shear failure in flat slabs, which are widely used in construction for their versatility and cost-effectiveness. The research explores innovative strengthening measures to enhance the punching shear capacity of flat slabs. The study employed Ultra-High-Performance Engineered Cementitious Composites (UHPECC) as a bonded concrete overlay on the tension side of the slab, combined with bonded carbon fiber-reinforced polymer (CFRP) sheets for indirect flexural strengthening and threaded steel bolts for direct shear strengthening. Five 1000×1000×100 mm square flat slabs with central circular columns were constructed and tested to collapse. The results demonstrated that the combination of UHPECC overlay, CFRP sheets, and threaded steel bolts significantly enhanced the punching shear capacity, with an increase ranging from 63 % to 92 % over the unstrengthened slab. The experimental findings confirm that the proposed technique effectively augments the punching shear capacity of flat slabs. Additionally, a finite-element (FE) model developed to predict the behavior of the tested slabs showed good alignment with the experimental results, validating the efficacy of the strengthening measures.