On May 20, NEXCO Chunichi (Central Nippon Expressway Company) opened to the press the site of the Tomei Tama River Bridge (Setagaya-ku, Tokyo; Kawasaki City, Kanagawa Prefecture), which is undergoing renewal work.
In the area under the company’s jurisdiction, approximately 60% of roads have been in service for more than 30 years, and some roads, such as the Tomei Expressway and Meishin Expressway, have been in service for more than 50 years. Although partial repairs have been made to ensure the integrity of these roads, it is difficult to restore them to their original performance, and many roads are undergoing large-scale renewal or repair to comply with stricter earthquake resistance regulations.
The Tomei Tama River Bridge is located on the first section that opened to traffic in 1968. More than 50 years have passed since its construction (completed in December 1966), and the bridge has deteriorated due to traffic exceeding 100,000 vehicles per day, which was not anticipated at the time of construction. Although partial repairs and reinforcement have been carried out, concrete delamination and exposure of internal reinforcing steel have been observed in the floor slabs, which form the floor of the bridge, making it necessary to take drastic measures.
In the past, when replacing floor plates, the bridge on the side where the work is to be done was closed to traffic to create a work area, and the remaining side was opened to two-way traffic. However, as mentioned above, this may cause severe traffic congestion in this section, where there are more than 100,000 vehicles per day. In the suburbs, temporary widening of the construction section could be used, but since it is adjacent to a dense residential area, this is not feasible in terms of cost and construction time. The “split slab construction” method was therefore considered for this project.
© Source travel watch