The Theory of Critical Distances to predict static and dynamic strength of notched plain concrete under mixed-mode I/II loading

The Theory of Critical Distances (TCD) is a powerful design tool capable of estimating the strength of notched/cracked materials by post-processing the linear-elastic stress fields ahead of the relevant stress raisers. The purpose of this paper is to reformulate the TCD to make it suitable for predicting the static/dynamic strength of notched unreinforced concrete subjected to Mixed-Mode I/II loading. The accuracy and reliability of the new extension of the TCD were checked using a large number of experimental results generated by testing plain concrete containing different geometrical features and tested under different loading rates and loading multiaxility. The predictions based on the proposed approach were seen to be within an error interval of ±30%. This level of accuracy is acceptable because it is within the scattering level of the experimental results used to calibrate the approach. These findings are promising and proving that this new reformulation of the TCD can be used to design notched plain concrete by modelling concrete as a linear-elastic, homogeneous, and isotropic material.