Statistical Analysis of Rebound Hammer Assessment on Reinforced Concrete Buildings

Abstract

This research explores the use of non-destructive equipment (Schmidt Rebound Hammer) to investigate the state of reinforced concrete buildings. A total of 138 Slabs, 266 Beams and 210 Columns were assessed as structural elements spread across six (6) different buildings. The columns, beams and slabs for the residential buildings have overall mean rebound compressive strength of 26.15 N/ mm2 20.18 N/ mm2 and 32.2 N/mm2 respectively. For the institutional buildings, the overall average rebound compressive strength for the columns, beams and slabs is 25.71 $N$/ mm2, 27.22 N/mm2 and 34.92 N/mm2 respectively. The columns, beams and slabs for the industrial buildings have overall mean rebound compressive strength of 30.27N/mm2, 24.23N/mm2 and 39.87N/ mm2 respectively. Rebound compressive strength values reduce as the height of the building increases. The standard deviation and coefficient of variance for a set of structural elements in the buildings showed high level of uncertainties and disparities which is an established factor in the use of the rebound hammer. This is a clear indication that a more robust method of analysis is needed for the interpretation and drawing of conclusions from the rebound hammer assessment.