Shear strength of high-strength concrete beams: Modeling and design recommendations

• Analytical model for prediction of flexural and shear resistance of HSC beams.
• Stress-block approach which takes into account the higher brittleness of HSC.
• Bond-splitting failure and concrete crushing of compressed strut are considered.
• Minimum and maximum amount of percentage of longitudinal bars and stirrups for HSC.

In the present paper, the flexural and the shear resistance of high strength reinforced concrete (HSC) beams with longitudinal bars, in the presence of transverse stirrups is analyzed both theoretically and experimentally. The experimental researches here presented are parts of previous researches carried out by the author. Researches refer to HSC beams with high percentages of steel bars failing in shear and in flexure. From the analytical point of view, a model based on the evaluation of the resistance contribution due to beam and arch actions including bond splitting and concrete crushing failure modes is developed and presented. The model was verified against available experimental results and those recently obtained by the author. Some of the more recent analytical expressions able to predict the shear and the flexural resistance of concrete beams were mentioned and design considerations are made referring to a ductile design of HSC beams. Finally, design recommendations were derived with the proposed model and compared with expressions given in most common codes.