Bridge monitoring combining laser scanning and ground penetrating radar

This paper presents a case study in which a Ground penetrating radar (GPR) system consisting of two antennas was used to investigate the condition of a bridge deck in central Sicily. The acquired data were analyzed for identifying the asphalt overlay thickness, concrete cover depth and deck thickness and location of the rebar reinforcement. The GPR survey was complemented with site investigation on layer thicknesses for calibration/verification purpose and complemented with a Terrestrial Laser Scanning system (TLS) to verify the bridge design characteristics (i.e., bridge deck curvature) information. The study shows that this methodology has significant merits on accurately assessing such bridge deck components when bridge design records are non-existing, and by using non-invasive methods such as laser scanning and GPR. The great advantage provided by the TLS technique is the possibility to obtain a 3D output model of the scanned element with the accuracy of the best topographic instruments in order to improve and verify GPR data interpretation.