ABSTRACT
Fatigue cracks in the longitudinal weld between deck plate and U-shaped rib have been increased in Hanshin Expressway company limited. Various kinds of methods to improve the fatigue durability were conducted such as using steel fiber reinforced concrete (SFRC) pavement on the steel deck. SFRC pavement is one of the effective methods for increasing the fatigue durability, but it has the disadvantage that it is necessary to carry out the traffic regulations. Hanshin Expressway Company Limited developed three countermeasures to improve the fatigue durability of U-shaped rib on orthotropic steel decks without the traffic regulation. All repair works of three methods are able to be completed under the deck plate. First method is adding thin steel plates in the vicinity of the welded joint, Second method is cutting the U-shaped ribs in the immediate vicinity of welded joint and connecting between the U-shaped rib and deck plate by L-shaped plates and studs bolts. Finally, the third method is filling the mortar into the inner space of U-shaped ribs. In this paper, outlines of three methods and results of the loading test at the actual bridge to evaluate their effect are reported.
