Size effect is the functional dependence of the ultimate stress of a given structure (“nominal strength”) on structure size. Since size effect has to do with the limited toughness of quasi-brittle materials, concrete structures exhibit a strong size effect, that…
Size effect is the functional dependence of the ultimate stress of a given structure (“nominal strength”) on structure size. Since size effect has to do with the limited toughness of quasi-brittle materials, concrete structures exhibit a strong size effect, that is enhanced by notches (“notch sensitivity”). Size effect appears whenever the structural behaviour shifts from ductile to brittle. Within this context, a size-effect law based on Neuber’s theory for stress concentrations around a notch is developed in this paper in the case of cementitious materials. The nominal strength σ is formulated as a function of the mechanical and structural N parameters, assuming that a dominant cohesive crack forms at failure and that this crack is similar to a pointed notch with a small plastic area at the tip. The proposed size-effect law is shown to fit satisfactorily many test results and to agree with the size-effect laws found in the literature.