Abstract
In Japan, many ordinary RC slabs of bridges in express ways are getting over 40 years old and have suffered from deterioration by fatigue due to heavily loaded tracks and simultaneous environmental attacks such as penetration of rainwater, salt of anti-frozen agent and freezing-melting reaction of concrete. Therefore, the express way companies, NEXCO decided to replace the deteriorated slabs into durable PC precast decks in 2015. Based on the loop joint developed by NEXCO having from 30 to 40 cm wide space for concrete casting, same types of reinforcing bar rapping were developed. As those methods are necessary much time for field works, however, shortening of those field works is required. To solve such problems, a mechanical joint called as Cotter joint, which was developed for airport aprons, was employed with scale down reformations. The joint is formed with C-shape cast iron and H-shape key cast iron. Without any reinforcing bar connection, both side precast decks can be connected by the cotter joints with 50 cm intervals and only 20 mm space between both precast panels, Therefore, the field works becomes very short of only bolting of H-shape iron into C-shape iron with simple screwdriver and injection of cementitious material. In the first one-third of the paper, the feature and mechanism of the Cotter joint is introduced. The remains describe the fatigue durability of the precast decks connected with the Cotter joints through the fatigue tests by the wheel running testing method. Extremely high fatigue durability getting over amply the requirement by NEXCO was proved and a useful S-N relation diagram was obtained.
