Health Assessment of a Pedestrian Bridge Deck using Ground Penetrating Radar

Abstract

Scanning concrete structures using ground penetrating radars (GPR) continues to be one of the most efficient methods for defect (i.e. crack, void and delamination) detection within concrete structures as well as detection of reinforcing bars damage due to corrosion. The aim of this study was to assess the structural health of a 45-year old pedestrian bridge deck. To achieve this, a number of experiments using a GPR system were conducted on a strong concrete floor with known construction drawings to detect cover depth and rebar orientations. After validating the GPR results through the experiments, the GPR system was used for nondestructive assessment of the pedestrian bridge deck. From the scanned results, the location and orientation of the reinforcing bar were established. In addition, the diameters of the bars was estimated by measuring the thickness of the hyperbola curves in the B-scans. The scanned output shows no signs of corrosion of reinforcement or damage of concrete in the form of delamination or cracking.