Effective Strength of Concrete Struts for the Strut-and-Tie Model of Prestressed Concrete Beams

The effective strength values of concrete struts should be accurately determined for the safe and rational strut-and-tie model analysis/design of structural concrete. In this study, the authors proposed effective strut strength equations specifically for the analysis/design of prestressed concrete beams within the strut-and-tie model. These equations took into account the effects of shear span-to-effective depth ratio, shear reinforcement ratio, magnitude of prestressing force, and prestressing steel ratio. To validate the accuracy of the developed equations, the authors predicted the failure strengths of 47 prestressed concrete deep beams, all of which were tested to shear failure. Both the existing and developed strength equations were used in the recommended indeterminate strut-and-tie model. The failure strengths estimated using the developed strength equations consistently aligned with experimental results, indicating their reliability and agreement.