REINFORCED CONCRETE STRUCTURE: NON DESTRUCTIVE IN SITU STRENGTH ASSESSMENT OF CONCRETE

When a study of the seismic damageability assessment of reinforced concrete (RC) structures is conducted, the characterization of the concrete used during the construction is of fundamental importance. According to the most recent seismic codes, the evaluation of concrete compressive strength is a fundamental step in the assessment of existing RC buildings. In fact in the assessment of seismic vulnerability of structures or in the evaluation of their seismic damage, we cannot ignore the correct evaluation of the materials' mechanical properties. Recent innovations in codes provide clear rules for assessing the safety and conduct of static strengthening on existing buildings. The type and number of in situ tests depend on the level of knowledge: Limited, Normal and Full. The knowledge level defines adoptable methods of analysis as well as the values of the Partial Safety Factors. A series of destructive and non-destructive tests were carried out on an important historic building in Reggio Calabria: the National Museum of "Magna Grecia". This paper outlines the structure which was tested and the principal results of the testing campaign. The results show the variation of the mechanical properties of the in-situ concrete, the reliability of the combined methods, the need to calibrate the strength obtained by non-destructive methods with the strength of cylindrical specimens (cores) which were extracted from the same structural elements in the proximity of the non-destructive test.