Regression Model to Estimate the Compressive Concrete Strength Based on Non-destructive Tests on Existing RC Buildings

The uncertainty in the concrete compressive strength is one of the most challenging issues in the seismic assessment of an existing RC building. This works characterizes the compressive concrete strength based on both in-situ destructive and non-destructive tests. A large set of data including (destructive) core tests and SONREB (rebound number S and ultrasonic velocity V) non-destructive test results, measured on the same structural elements of different existing RC buildings, has been collected. Then, a regression model is employed in order to derive predictive expressions for calculating the compressive concrete strength Rc based on the ultrasonic velocity V and on the rebound number S measurements. The work shows also that linear logarithmic regression (V-Rc) can be used instead of the multilinear logarithmic regression (V-S-Rc) without significant loss of accuracy.