Predictive models for evaluating concrete compressive strength in existing buildings

An accurate assessment of the concrete compressive strength is a fundamental step towards evaluation of existing rc structures under gravity and seismic loads. The results obtained in previous studies by the authors on current destructive and non-destructive methods, dealing with buildings located in the Italian Region of Tuscany, show that the combined Sonreb method, considering different variants found in the relevant literature, consistently provides the best prediction of strength compared to the sclerometric and to the ultrasonic methods, being characterized by an high stability. In this paper, considering the same data base of experimental data used in the previous studies, new models are proposed to improve the prediction of concrete compressive strength as obtained from the sclerometric and ultrasonic methods, also to verify their capability to reach similar reliability to that of the Sonreb method.