This study looks to propose a hybrid soft computing approach that can be used to accurately estimate the shear strength of reinforced concrete (RC) deep beams. Support vector regression (SVR) is integrated with three novel metaheuristic optimization algorithms: African Vultures optimization algorithm (AVOA), particle swarm optimization (PSO), and Harris Hawks optimization (HHO). The proposed models, SVR-AVOA, -PSO, and -HHO, are designed and compared to reference existing models. Multi variables are used and evaluated to model and evaluate the deep beam’s shear strength, and the sensitivity of the selected variables in modeling the shear strength is assessed. The results indicate that the SVR-AVOA outperforms other proposed and existing models for the shear strength prediction. The mean absolute error of SVR-AVOA, SVR-PSO, and SVR-HHO are 43.17 kN, 44.09 kN, and 106.95 kN, respectively. The SVR-AVOA can be used as a soft computing technique to estimate the shear strength of the RC deep beam with a maximum error of ±3.39%. Furthermore, the sensitivity analysis shows that the deep beam’s key parameters (shear span to depth ratio, web reinforcement’s yield strength, concrete compressive strength, stirrups spacing, and the main longitudinal bars reinforcement ratio) are efficiently impacted in the shear strength detection of RC deep beam.

The ductility and capacity of reinforced concrete beam-column connections depend mainly on the concrete’s strength and the provided reinforcements. This study investigates numerically the role of low-strength concrete in beam-column joints utilizing ABAQUS software. In this simulation, a newly developed stress-inelastic strain relationship for both confined and unconfined low-strength concrete is used. This study recommended a specific value of the concrete dilation angle for both substandard and standard joints. Also, stirrups’ yield strength value was found to play an insignificant role in improving the shear resistance of such joints with low-strength. In addition, the joint shear strength prediction using empirical models that implicitly consider the stirrups contribution in improving joint resistance was found to be better than the prediction of other models that explicitly consider the stirrups’ presence. The numerical results also showed that the use of a diagonal steel haunch as a joint retrofitting technique significantly increases the joint shear capacity and changes its brittle shear failure into a ductile beam flexural failure.

Being a critical component of reinforced concrete (RC) structures, retrofitting beam-to-column joints (BCJs) has been extensively investigated, particularly for substandard designs. These investigations attempted to avoid possible shear failure in the joint region; however, careful consideration of the most effective and potentially practical solution was limited. Therefore, this study systematically evaluates three retrofitting techniques that are assumed to be both effective and replicable in real applications. The three techniques were carbon-fiber-reinforced polymers (CFRP), steel angles with pretension bolts, and U-shaped steel bars. First, finite element (FE) models were validated against experimental data to confirm the accuracy of the proposed numerical model. Then, a parametric study was conducted to explore the effect on the joint performance. The considered parameters for CFRP: bond shear stress and the ply count; for steel angles with pretension bolts: angle’s leg size, component thickness, and bolt diameter; for U-shaped bar technique: diameter and length of the bar. Based on the parametric analysis, a comparison between the three techniques was performed to achieve the most robust designs possible. Results indicated that the overall joint strength in terms of ultimate load was enhanced using the CFRP and U-shaped techniques compared to the control joint by 103.93% and 43.55%, respectively. Steel angles with pretension bolts exhibited the highest performance, with a 148.50% increase in ultimate load, and was the most effective in relocating the failure to the beam.