Abstract
The study aimed to assess the reliability and safety of simply supported reinforced concrete beams, both with and without shear reinforcement, based on the design criteria outlined in Eurocode 2. A total of fifteen reinforced concrete beams were created, each measuring 750mm x 150mm x 150mm and reinforced with 12mm diameter bars. These beams were cast with varying reinforcement ratios (1.0%, 1.5%, 2.0%, 2.5%, and 3.0%) and a target concrete strength of 25N/mm2. The shear strength of the beams was tested using a three-point bending test, and the Probability Distribution Function (PDF) of the reinforced concrete beam was determined using EasyFit software through the Kolmogorov-Smirnov Test. The reliability analysis was conducted using COMREL, employing the First Order Reliability Method (FORM), Second Order Reliability Method (SORM), and Monte-Carlo simulation methods. The outcome from the findings showed that the stochastic parameters used for the reliability analysis had reinforcement ratio, concrete characteristic strength, steel yield strength, and beam shear strength values of 1.34%, 22.05N/mm2, 389.84N/mm2, and 8121.56N respectively, whereas the steel reinforcement ratio and beam shear strength significantly fits a Log-normal distribution, while the concrete characteristic strength and steel reinforcement yield strength fits a normal distribution. The FORM and SORM reliability index values of the beam shear capacity are 3.795 and 3.791 with a failure probability of 7.38 x 10-5 and 7.52 x 10-5 respectively. The sensitivity analysis showed that concrete compressive strength is the most sensitive, followed by the steel reinforcement ratio, while the partial safety factor derived was 0.98 for the reinforcement ratio and 0.74 for the concrete compressive strength with a cumulative safety factor value of 0.725. Hence, it was recommended that for safety reasons, the partial safety factor for the shear capacity of reinforced concrete beams should be taken as 138 ρl fck, this represents a 38% increment as against the 100 ρl fck in the Eurocode design of beam shear capacity.

Key words: Calibration, Shear strength, Steel reinforcement, Reinforced concrete, Beam, Eurocode 2.