Ground-Penetrating Radar,Chain Drag,and Ground Truth

Determining the degree of degradation of a bridge can be one of the most difficult problems that infrastructure inspectors face. While traditional bridge inspection methods such as visual and chain drag will always play a role in bridge condition assessment, more sophisticated and accurate techniques such as ground-penetrating radar (GPR) are gradually gaining acceptance by departments of transportation. GPR is a nondestructive evaluation method that can be used to assess the integrity of roads, pavements, bridges, and buildings. It uses high-frequency electromagnetic waves at the microwave or radio frequency range to examine the subsurface condition. This technique is used to detect features, such as cracks, voids, and delamination. An evaluation was made of GPR effectiveness in condition assessment compared with effectiveness of chain drag and ground truth method (cores) of two concrete bridge decks. Results show that the GPR method has potential as a practical and economically viable means for bridge assessment.