초록
The footing of a bridge is a very essential part that support the whole load induced by the bridge itself and the traffic as well. However, once a bridge is built, the footing is buried under soil so the footing is invisible from outside. Therefore, the safety or condition of the footing is very difficult to estimate. Not only the length of the imbedded part of the footings but also the type of footings are unknown once the design record is gone. Some nondestructive techniques can be used to evaluate invisible part of the footings but the results have not been successful yet. Using GPR (Ground Penetrating Radar), which has been used for the nondestructive evaluation in military purposes, the condition assessment of the footings have been successfully conducted in this research. The field evaluation and laboratory tests have been conducted to find effective factors in the condition assessment of the footings. The equipment and basic theory of the GPR has been presented. The field test results show that the GPR can be successfully used for the safety evaluation of the footings. More test results and field data are needed for more precise evaluation of the footings.