From on-site marking to handling volumes of data
When testing are inforced concrete element,GPR typically provides a clear insight of all structural details, including its geometry and stratigraphy, its steel reinforcement and any metallic or plastic embedded object. Hit-prevention investigations, (prior to drilling, coring or cutting) are often handled with the simple execution of an adequate numbers of linear scans while marking in real time the surface with a marker or spray paint. On the contrary, whenever we are dealing with projects involving a structural assessment, the GPR investigation is commonly used to makeup for the lack of detailed documentation about the reinforcement and the structural details, and a full reporting is needed. In these cases the strategy will focus on the systematic collection of profiles along a defined square grid and the following post-processing of the whole set of data. By means of the proper interpolation between parallel and orthogonal lines, a full volume can be compiled, delivering an immediate visual representation of the inner structure. Two key points are to be kept in mind at this stage, ideally combining the fundamentals of “old school” and“new school” GPR:
- Making the best use of the slicing of the solid volume along any given plane to provide 2D views, enhancing hard-to-see features and essential for “removing subjectivity from the data”
- Always keep an eye on the raw data for confirming the picked objects, paying attention not to befooled by possible fake artifacts arising during the processing
