An automated signal processing system for the signature analysis of radar waveforms from bridge decks

Abstract

This paper describes the results of a project which employed impulse radar to detect faults existing beneath the surface of an asphalt-covered bridge deck at Papineau Creek, Ontario. A simple but enlightening mathematical analysis is provided which accurately predicts the waveforms actually observed. The methodology clearly demonstrates the usefulness of impulse radar as a diagnostic tool in remote sensing. Amongst the problems discussed and solved are: the identification of faults due to debonding, scaling, and delamination; the measurement of asphalt thickness at selected locations on the bridge deck and hence the determination of average thickness over the entire bridge deck; and the automated processing of the data using a computer. A comparison of the radar detected faults with those detected using conventional methods is provided. A set of parameters has been developed which permits data to be reduced to a simple set of measurements that can be plotted for visual inspection. Dans cet article, on decrit les r6sultats d'un projet dans lequel on a utilise un radar impulsionnel pour detecter les defauts sur la surface d'un pont asphalte a PapineauCreek, Ontario. On utilise une methode d'analyse simple qui calcule avec precision les formes d'onde observees. La methodologie demontre clairement l'application du radar impulsionnel comme un outil pratique dans les applications de detection des objets eloignes. On etudie les problemes suivants: l'identification des defauts dus aux "debonding, scaling" et a la "delamination." On fait une etude com parative pour la detection des defauts observes par la methode proposee et par d'autres methodes usuelles. On etablit un ensemble des parametres qui permet la reduction des donnees en un ensemble de mesures pour inspection visuelle. |

Detection of Reinforced Concrete Blocks Using Two-Port Microwave CSRR Sensor

“…The time that manual inspections could take depends on the severity of the concrete degradation. There are also other nondestructive testing (NDT) techniques that are practiced in cracks' detection in concrete or cementbased materials, including ultrasonic [18]- [19], infrared thermography [20]- [21], impulse radar testing [22]- [23] and vibration techniques [24]. Two commonly deployed methods using ultrasonic technique in order to detect defects in reinforced concrete materials are ultrasonic tomography (UT) and ultrasonic pulse velocity (UPV).…”

Comparison of the Accuracy of 2D vs. 3D FDTD Air-Coupled GPR Modeling of Bridge Deck Deterioration

“…Ground Penetrating Radar (GPR) is a popular choice for nondestructive testing of civil infrastructure for early detection of deterioration due to freeze-thaw processes and corrosion [3][4][5][6][7][8]. Early detection can help to avoid costly bridge deck replacements, which currently range from $1 to $3 billion per year [9].…”

“…The accuracy trade-offs between the two models will be discussed and conclusions drawn for which applications the 2D model may be adequate. Since the focus of this manuscript is on the comparison of 2D and 3D FDTD models, readers are referred to [1][2][3][4][5][6][7][8][9] for detailed information on the FDTD formulation and [10][11][12][13][14][15][16] for detailed information on GPR data processing.…”

Forward Time Domain Ground Penetrating Radar Modeling of Scattering from Anomalies in the Presence of Steel Reinforcements

“…Quantitative imaging with GPR is required to identify and diagnose hidden defects such as delamination, voids, and changes in material properties signifying possible change in material strength. In practical systems data interpretation for bridge deck deterioration evaluation is based on detection of reflection and attenuation extremes in the GPR signal produced by variations in moisture=chloride caused by freeze-thaw processes and corrosion [5][6][7][8][9][10]. While automatic processing techniques do exist, final interpretation and diagnostics of subtle issues remains, primarily, a visual interpretation to the GPR scan.…”