In NEXCO Central Japan’s service area, approximately 160 km of bridges (slabs and girders), 4,977 earth structures, and 35 km of tunnels were targeted, and the project cost was 1.01 trillion yen, a truly large-scale project. The replacement of the floor slabs of the Kiyomidera Bridge is a part of the project.
The objective is not to partially repair the building, but to make it perform and function as well or better than when it was first built by applying the latest technical knowledge and technical standards.
This project is part of a highway renewal project (large-scale renewal and repair). Of the 9,000 km of expressways in service in Japan, approximately 40% (3,700 km) have been in service for more than 30 years, and are deteriorating over time due to the increase in heavy vehicle traffic, the use of anti-freeze in cold regions, and other factors.
On January 15, NEXCO Central Japan’s Tokyo Branch opened to the press the site of the Seikenji Bridge slab replacement work being conducted between the Fujikawa Smart IC and Shimizu JCT on the Tomei Expressway (E1).
Replacement of floor slabs on the Seimidera Bridge, which carries the Tokaido Shinkansen bullet train overhead.
Fuji Maintenance and Service Center, which is in charge of the construction work, manages three lines, 123.4 km: Tomei Shimizu IC to Numazu IC (44.5 km), New Tomei Shin-Shizuoka IC to Nagaizumi Numazu IC (53.7 km), Shin-Shimizu JCT to Shimizu JCT (4.5 km) and Shin-Shimizu JCT to Tomisawa IC (20.7 km) on the Central Japan Expressway The company manages three lines, 123.4 km in length.
Mr. Tsutomu Kondo, Director of Fuji Maintenance and Service Center, Tokyo Branch Office of NEXCO Central Japan, gave an overview of the Kiyomidera Bridge (Shimizu-ku, Shizuoka Prefecture), explaining that it is located between the Tomei Fujikawa SIC and Shimizu JCT, and is part of a series of multiple tunnels and bridges, and that it crosses the Tokaido Shinkansen Line.
The 260-meter bridge (between P1 and P4 piers) has been in service for more than 50 years since April 1968, and the average daily cross-sectional traffic volume is approximately 36,000 vehicles. Daily inspections have so far revealed 279 damaged sections, and in FY2023 construction will be carried out between piers P1 and P2 and between piers P3 and P4 on the up line, followed by construction between piers P2 and P3 directly above the Tokaido Shinkansen and on the up line in sequence.
The Tomei Expressway will be closed to traffic at night and other restrictions will be in effect for 74 days from January 9 to March 22, 2024. The restrictions will be in effect for a total of 74 days from January 9 to March 22, 2024, with the overtaking lane restricted during the daytime on weekdays from January 9 to February 7, and the road closed at night (18:00 to 6:00 the following day). From February 8, the lanes will be restricted continuously day and night, and wall railings will be installed.
In these slab replacements, it is common to “cut the existing slab after cutting the pavement, lift it up with a crane and remove it,” “install the new slab with a crane,” “pour concrete at the joint to integrate it as a slab,” “waterproof it and hang pavement to complete the process.
Since the road closure is limited to 12 hours at a time this time, temporary steel slabs will be installed after the existing slab is removed and the road closure is lifted. The next day, the temporary steel slab will be removed and the new slab will be installed.
The new slab is a factory-made precast slab measuring 12.1 x 2.43 m (length x width) and weighing 28.6 tons. The C-shaped hardware on the side of the slab is connected to the H-shaped hardware and tightened with bolts, and then filled with a quick-drying joint agent that hardens in about three hours to complete the waterproofing and pre-paving work. By eliminating the need for the conventional process of reinforcing steel and pouring concrete, delays caused by rain or snow can be minimized.
A total of 30 slabs are to be replaced, 11 between P1 and P2 and 19 between P3 and P4. 2 slabs each will be replaced in a single day: removal of existing slabs, installation of temporary steel slabs, and replacement of temporary steel slabs with new slabs.
During the construction period, two types of barriers will be used: the “SSS (Speedy, Spike, Sjoint) Guard,” which will be placed in areas where wall railings have not been installed, and which can be installed for 40 m per hour and can be installed or removed only in one section, making it highly workable. The other is called a “Vulcan Barrier” to secure the work zone. In addition, the “tapered” section, which reduces the number of lanes, will be extended from 300 m to 360 m. In addition, the regulatory materials will be arranged in a quadratic curve, with the angle increasing toward the end of the section, instead of a straight line, to reduce accidents involving contact with the regulatory materials.
The closure is not expected to cause major traffic congestion since the New Tokyo-Nagoya is the main detour route. Mr. Kondo explained, “We expect traffic volume of about 7,000 vehicles in 12 hours, but there is no congestion forecast at Shimizu JCT, Shin-Shimizu JCT, and the bottleneck Fujinomiya Tunnel, and none has actually occurred. At the same time, tow trucks will be placed on standby at two locations in case of accidents on the New Tomei.
As for the parallel public road, “we verified whether the road closure from 6:00 p.m. to 6:00 a.m. or from 7:00 p.m. to 7:00 a.m. would have a greater impact, and found that the latter would have a greater loss time,” so the company has minimized the impact by setting the road closure at the former time.
In addition, since the Yui PA and Fujikawa SA will no longer be available, parking spaces for large vehicles will be expanded as a countermeasure to congestion at rest facilities. The number of parking spaces for large vehicles will be increased from 82 to 173 at Shimizu PA, from 146 to 157 at Suruga Bay Numazu SA, and a temporary parking lot for 55 vehicles will be set up at the Shin-Shimizu IC toll booth. The temporary parking lot will be open from 6:00 p.m. to 6:00 a.m. until February 9 (or until construction is completed). The temporary parking lot will be available for medium, large, and oversized ETC vehicles that re-enter in the forward direction within 2 hours of their exit time, and will be charged the same rates as those for direct traffic.
At the same time, if the traveler takes a detour route to use the uphill route, the toll will be adjusted so that it will not be higher than the toll for direct use of the construction section.
© Source travel watch
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