▲Assembled bridge girders
(right in the photo)
▲Bridge girder fixed on the bridge piers
(The road running below is the Tomei Expressway.)
The inbound and outbound lines between the Gotenba and Numazu Interchanges on the Tomei Expressway were closed from 19:00 on Saturday, November 18 to 7:00 on Sunday, November 19, 2006.
During that period, the construction work of the Komakado Bridge was carried out on the Second Tomei Expressway, which crosses the Tomei Expressway near the Komakado Parking Area.
Bridge girders for the inbound and outbound lines were assembled alongside the construction work zone, and were moved horizontally and erected over the Tomei Expressway. JFE Engineering participated in the construction work on the outbound line as a joint venture.
The steel bridge was about 200 meters long and weighed about 1,800 tons. In this project, in the course of one night, we moved it 71 meters and then placed and temporarily fixed it onto the bridge piers. This was one of the largest-scale horizontal movement works performed in Japan. The project was quite unique in that the inbound and outbound lines had to be moved horizontally at the same time and loaded onto the bridge piers on the same day. On the outbound line in particular, where construction work had to be performed ahead of the inbound line, we had to perform everything on time without wasting a second.
The bridge girders were assembled on bents, and temporary rails were laid on the location of installation to move the bridge horizontally.
The movement of the bridge girders began at 19:30. In order to move the girders quickly, two jacks were mounted on their front and rear sides. The bridge girders were pushed forward by extending the rear-side jack with the rear end fixed.
Next, the front end of the front-side jack was fixed, and it was contracted to draw the bridge girders forward. These steps were repeated, and the movement of the bridge girders was completed at 24:30. The bridge girders were then loaded onto the three bridge piers. They were lowered 45 cm through four operations while adjusting the central area and both ends. This process took two and a half hours to complete. After this process, the bridge girders were temporarily fixed, the equipment and materials were removed, and the site was cleared up. The traffic closure was called off at 7:00, as scheduled.
In order to move such a heavy object in a limited time during the night, we considered every possible situation and performed numerical simulations to confirm certainty and safety
What is most important, however, is onsite practical ability.
The guidance of the client Central Nippon Expressway Company, and the skills and teamwork of the staff members of the affiliated companies and the joint venture provided support for the construction work to ensure its perfection.