ABSTRACT
Strength assessment of existing buildings is a key challenge for structural engineers who need to feed structural computations with material data. The quality of assessment is limited due to sources of uncertainties arising at various levels and caused: by the testing method, by systematic interferences with the environment, by random interferences (due to material intrinsic variability), by human factor influence and by data interpretation, including errors in the model between what is measured and what is looked for. Rebound measurement and ultrasonic pulse velocity (UPV) are among the most widely used NDT methods regarding concrete strength assessment. A main point is that of “calibration”, i.e. that of building and using a reliable relationship between NDT values and strength.
