Experimental shear failure of reinforced concrete beams in fire conditions

This paper presents the results of a test campaign of twelve reinforced concrete beams without transverse reinforcements under four-point bending and thermal loading in order to achieve their shear failure in fire conditions. Midspan deflection, temperature, shear strength and crack angle of the beams were measured throughout the campaign. Furthermore, the experimental shear strength of the beams at ambient temperature was compared to predictions from ACI Code-318–25 and EN 1992–1–1. Then, the experimental shear strength of the beams in fire conditions was compared to predictions from EN 1992–1–2 and those derived from a design model based on the upper bound kinematic approach of the yield design theory. Such comparisons were made using different values of the effectiveness factor applied to the compressive strength of concrete, available in the literature, making it possible to show the influence of such a factor on the comparative results.