Shear strength of concrete members without transverse reinforcement: A mechanical approach to consistently account for size and strain effects

Influence of flanges on the shear‐carrying capacity of reinforced concrete beams without web reinforcement

“…As discussed in References , the activation of the various STA depends a great deal on the critical shear crack pattern and its associated kinematics. With respect to T‐beams without transverse reinforcement, the critical shear crack pattern observed is slightly different to the one observed at a rectangular section beam.…”

“…With respect to the influence of shear slenderness on rectangular concrete members, two different responses have traditionally been acknowledged: beams with shear span to depth ratio a / d lower than approximately 2.5 are capable of carrying partially the load by direct strut (arching action) as illustrated in Figure f (where a is the shear spam, and d is the effective depth). For rectangular beams with higher shear span to depth ratio, arching action is no longer governing, and beam STA (Figure a) control the shear strength . This change of the governing model can be observed, for instance, in the results of a test campaign carried out by Swamy et al and illustrated in Figure , where an abrupt change in the slope of the curve occurs at a value a / d ≈ 2.5.…”

“…As a result of what has been illustrated in Figures and , the ratio h f / d , where h f is the depth of the flange, is essential to evaluate the shear strength of a T‐beam. In the following sections, this will be investigated by using the mechanical model of the Critical Shear Crack Theory (CSCT) …”

“…The CSCT is a rational approach to assess the shear strength of the slender concrete members without shear reinforcement . The CSCT claims that the plasticity‐based solutions with an inclined compression strut‐carrying shear (Figure f) overestimate the shear strength when a critical shear crack develops through the theoretical strut.…”

“…The CSCT takes into account the different STA presented in Figure by assuming different contributions for each based on the shape of the critical shear crack and its associated kinematics. It is shown by means of analytical integration of the stresses that the shear strength at failure depends on the opening, roughness, and fracture energy properties of the critical shear crack …”