Regarding bridge structure maintenance and inspection, this study was conducted to replace the current system, in which bridge diagnostics specialists ride on inspection vehicles to perform visual inspections, with a robotic system equipped with a small camera. The new system would greatly reduce the effort required, enhance the safety of inspectors and provide more accurate and efficient data that are objective and quantitative. For this purpose, a new robotic inspection system was developed for field test which was performed on Ahyun overpass bridge. Field test results are described to prove the on-site applicability.

The increase of traffic over a bridge has been emerged as one of the most severe problems in view of bridge maintenance, since the load effect caused by the vehicle passage over the bridge has brought out a long-term damage to bridge structure, and it is nearly impossible to maintain operational serviceability of bridge to user's satisfactory level without any concern on bridge maintenance at the phase of completion. This study has the aim of development on automated inspection system to lower surface of bridge superstructures to replace the conventional system of bridge inspection with the naked eye, where the monitoring staff is directly on board to refractive or other type of maintenance vehicles, with which it is expected that we can solve the problems essentially where the results of inspection are varied to change with subjective manner from monitoring staff, increase stabilities in safety during the inspection, and make contribution to construct data base by providing objective and quantitative data and materials through image processing method over data captured by cameras. By this system it is also expected that objective estimation over the right time of maintenance and reinforcement work will lead enormous decrease in maintenance cost.

The amount of newly-built bridges has been gradually reduced so that the importance of maintenance for existing bridges which has a long services period is issued. Therefore, the maintenance budget for existing bridges is going to be consistently increased. It is needed that a reasonable decision-making methodology for existing bridge maintenance is required to effectively use the limited maintenance budget. In this study, a method of the structural vulnerability evaluation is newly suggested as the one of the evaluation stage for developing a reasonable decision-making methodology.