Identification and localization of GPR overlapped signals from double-row rebars

Abstract In radar detection of concrete structures, rebars cause strong reflections, and the waveforms of double-row rebars overlap, making it difficult to identify the echoes from the second row of rebars. Due to structural interference between the rows, the signal from the second row is superimposed with the first-row signal, increasing the overall amplitude. A peak point extraction algorithm is designed to analyze signal changes caused by signal superposition in A-scans. The algorithm selects, corrects, and locates the superimposed signals to determine the characteristics and positions of the second-row rebars. In a tunnel, ground penetrating radar data was automatically analyzed, and the second-row rebar positions were marked after correction. The results show that over 85% of the sampled data for the double-row rebar spacing has a relative error of less than 5%, ensuring the rebar layout in the tunnel meets safety standards.