Testing low strength concrete of collapsed frame buildings

Within the scope of measurement of in-situ material properties, the paper presents results of two studies carried out by the Authors for forensic investigations of concrete properties in existing reinforced concrete frame structures collapsed during the 2009 Aquila earthquake. The two edifices were built in the 1960s; the results provide data on low-strength material property measurement. Cores were extracted: 53 specimens in two series for the first building and 16 in the second. Compression tests were carried out following EN12390-3, providing data on density, compression strength and ultrasound velocity. Non-Destructive Testing with SONREB measurements were also carried out in the first building. The test results are analyzed and discussed in relation to the design documents and the Italian code specifications at the time of the design of the building. The conclusions show that the concrete quality was very poor in relation to low quality construction practices.