On the Use of Ground Penetrating Radar for Bridge Deck Assessment

Abstract

Many transportation agencies require the condition assessment of concrete bridge decks as part of scheduled maintenance programs. Traditional bridge deck inspection methods include: hammer sounding and chain drag techniques. The interpretation of such techniques' results depends on the operator and may produce highly variable results. Ground Penetrating Radar (GPR) has been extensively used and become an invaluable technique due to its high level of accuracy, being Non-destructive testing (NDT), low cost and simple operation. GPR technique is used for detecting the steel rebars embedded in the concrete, determining the concrete slab thickness, the asphalt layer thickness as well as developing a corrosion map for the steel rebars. This study presents the recap of using GPR technique in inspection of a bridge deck located in El- Kobba suburban in Cairo. A clear methodology for the data collection, processing and analysis of collected raw data is presented. Data is first processed, then Numerical amplitude method is used in the analysis. The study also clearly shows how to determine: 1) the slab thickness, 2) asphalt layer thickness, and 3) the arrangement of steel rebar of the slab. Thus, GPR technique can be used to make structural assessment and obtain the structural information without destruction to the element as well as structural checks and analysis can be performed for the bridge decks.