Experimental Investigation of Fixed-Ended RC Beams with Circular Post-Installed Openings Across Different a/d Ratios

OpenAlex İngilizce

This study experimentally investigated the structural behavior of reinforced concrete beams with circular openings created by core drilling in the midspan and shear span regions under fixed-ended boundary conditions. A total of 21 full-scale beams with shear span-to-effective depth ratios (a/d) of 1.25, 1.75, and 2.25 were tested under a four-point bending setup. After concrete hardening, 100, 200, and 300 mm diameter openings were introduced by core drilling. The results showed that the effect of opening location on load-carrying capacity varied with the a/d ratio. In the a/d = 1.25 and 1.75 series, openings in the shear span caused more pronounced reductions, whereas in the a/d = 2.25 series, midspan openings became more influential. Increasing the opening diameter reduced both load-carrying capacity and energy dissipation capacity, and this reduction varied with opening location and a/d ratio. Openings in the shear span led to shear failure in the a/d = 1.25 and 1.75 series, whereas flexural effects became more pronounced in the a/d = 2.25 series. Nevertheless, 300 mm openings caused shear failure even in beams expected to exhibit more flexure-dominated behavior.