2015. . No. 2(68) - Jun 2015, pp. 45-47
Ground Penetrating Radar Imaging of Concrete at a Nuclear Power Plant
Introduction. The article describes the author’s experience using GPR as an NDT technology to image structures within a concrete slab at a nuclear facility to assist intelligent placement of anchor bolts for a new crane hoist. Furthermore, the article shows the capabilities of this technology by leading them step-by-step through a project that required on site results in a highly restrictive environment.
Method. GPR for concrete scanning applications uses high-frequency radio-waves (1 GHz) to generate images of the concrete slab by analyzing reflection patterns. Multiple scans were acquired on a grid to generate data that were processed and interpreted on site.
Results. The GPR data revealed the position and cover depth of upper and lower rebar mats, conduit and beam stirrups. This information was transferred on the concrete surface with markings in addition to digital images for reporting.
Conclusion. GPR rapidly imaged the features within a concrete beam with minimal disruption to operations and no requirement of additional safety precautions. It has become an essential component of building forensic services.
Keywords: GPR, imaging, safe-alternative, reflection, building forensics, depth-slice