Formulation of shear strength of slender RC beams using gene expression programming, part I: Without shear reinforcement

• GEP algorithm is introduced for the shear capacity modeling of RC slender beams.
• A simplified formula is obtained for the shear capacity of beams without stirrups.
• The proposed model performs superior to the ACI, EC2, CSA and NZS code models.

In this study, a new design equation is derived to predict the shear strength of slender reinforced concrete (RC) beams without stirrups using gene expression programming (GEP). The predictor variables included in the analysis are web width, effective depth, concrete compressive strength, amount of longitudinal reinforcement, and shear span to depth ratio. A set of published database containing 1942 experimental test results is used to develop the model. An extra set of test results which is not involved in the modeling process is employed to verify the applicability of the proposed model. Sensitivity and parametric analyses are carried out to determine the contributions of the affecting parameters. The proposed model is effectively capable of estimating the ultimate shear capacity of members without shear steel. The results obtained by GEP are found to be more accurate than those obtained using several building codes. The GEP-based formula is fairly simple and useful for pre-design applications.