Evaluation of Precast Pre-post-tensioned Concrete Bridge Beams with the Use of GPR Method

Precast pre-post-tensioned concrete beams are commonly used in transport engineering. Significant number of bridge structures is being built with the use of precast girders due to their advantages such as quick construction process, moderate cost and reduction of scaffolding and shuttering works. To avoid failures, precast structural members must be subjected to strict quality control that requires the use of the non-destructive testing methods. One of the most suitable NDT methods for precast girders inspection is the Ground Penetrating Radar method.The aim of the research described in this paper was to evaluate the parameters of prefabricated 'T' bridge girders with the use of the Ground Penetrating Radar method. The beams were investigated upon the producer's request in order to assess the correctness of the production process. The georadar measurement was conducted and the raw data were processed with dedicated software. As a result of the study, a series of radargrams were attained. Based on these data, the rebar location and cover depth as well as pre-tensioning and post-tensioning cable trajectories were determined. The results allowed defining capabilities and limitations of the Ground Penetrating Radar method with regard to quality control of prefabricated concrete elements.