Repainting of Seto-Ohashi Bridge for increase of durability

The Seto-Ohashi Bridge is located in the center route of three routes that connect Honshu, Japan’s main island, and Shikoku. It consists of three suspension bridges, two cable-stayed bridges, and one truss bridge on the strait and some viaducts on the islands. They are highway-railway combined bridges whose overall length is approximately 10 kilometers. The bridge, mainly comprised of steel structures, is in a severe corrosive environment. Therefore, the heavy duty coating system is used to prevent corrosion. The bridge has served for 18 years since the opening, and allover repainting program, which makes LCC minimum, started with modified paint system for 1,800,000 m2 of repainting area. In order to develop the repainting schedule, the thorough coating inspections to grasp the deteriorated condition and the prediction of the coating exhaustion were implemented. Then, the priority and the timing of repainting were determined based on the results. The careful quality control is conducted to obtain the high quality coating film in the field repainting work.