Structural behavior of reinforced concrete column having mid-span transverse opening: Experimental study and numerical analysis

This study presents five different strengthening techniques to mitigate the axial load-carrying capacities of reinforced concrete (RC) column having mid-span transverse opening under different loading conditions. These techniques are concrete compressive strength (f c’ ), column size, rebar size, rebar size and concrete f c' , and internally wrapped carbon fiber reinforced polymers (CFRP) strips. Experimental findings revealed that providing mid-span transverse opening (50 mm diameter) in RC columns (cross-section: 200 mm × 200 mm) reduces its axial load-carrying capacity by 20.99 %. However, with increased cross-section (230 mm × 230 mm) and rebar size (4N19), the axial load-carrying capacity of RC column was improved by 18.75 % and 9.38 %, respectively, compared to the RC column having no opening. The eccentric loading conditions showed a direct relationship between the bending moment and eccentricity of the RC column with increased cross-section. However, no obvious decline effect was found on the structural behavior of all RC specimens against cyclic loading. Furthermore, a non-linear finite element model (FEM) was established and showed good agreement with the experimental results under a marginal error of 3.71 %. Lastly, parametric analysis identified that cross-section and rebar size have the major influence on improving the axial load-carrying capacities of RC specimens having mid-span transverse opening under concentric and eccentric loading.