Sustainable assessment of structures and materials using ground penetrating radar (GPR)

Ground penetrating radar (GPR) is a non-destructive, non-invasive device that can be used to investigate materials in buildings, structures and the ground. Its use relies on recording the reflections of radar waves that are transmitted into materials. This paper provides an overview of GPR, a brief explanation of its principles of operation and application, suggests areas where its use may be appropriate in the context of buildings and structures, and includes some case studies from engineering investigations conducted by the author to highlight examples of the information it can provide. The technical information that GPR can commonly provide includes material depths and thicknesses, locations of excessive moisture or deterioration, and the location of steelwork within construction materials. Whilst reducing uncertainty in data obtained from building and structural investigations, other advantages compared to alternative intrusive investigations include less time and costs for investigations, less disruption to users of the building / structure, and less material required for subsequent repair and maintenance work. This paper also highlights, however, some limitations of the technique which should be considered in order to optimise the success of GPR investigations, such as the necessity for specialist knowledge in operation and data interpretation, and the limited GPR signal penetration within certain materials. Overall, the potential for use of GPR in the determination of material and structural properties in the built environment is highlighted.