There are 730,000 road bridges nationwide, out of the social capital. Among them, the percentage over 50 years after the construction will reach 60% in 10 years. (according to the published materials by the Ministry of Land, Infrastructure, Transport and Tourism).
The total length of a highway bridge using reinforced concrete floor slabs, which requires immediate large-scale renewal, is approximately 230km. For this reason, NEXCO East, NEXCO Central and NEXCO West plan to replace these floor slabs with a cost of approximately 1.65 trillion yen altogether.
(According to the presentation materials by NEXCO 3 companies)
On the other hand, how to construct a highway bridge using the current reinforced concrete slab, is to pre-manufacture reinforced concrete floor slab in the factory, then to arrange them at regular intervals in the site of construction, and lastly the floor slabs are connected to each other by placing "filling concrete" at the intervals.
This work requires not only a lot of manpower and heavy equipment, but also a huge amount of time especially for positioning the floor slabs. For example, under the current situation, it takes 30 minutes or more just to arrange one floor slab at regular intervals.
New joint “VanLoc” for replacement floor slabs
"VanLoc" has realized an epoch-making construction method using precast PC floor slabs to eliminate filling concrete, which has been nowadays considered unavoidable.
It is an innovative joint that can complete the floor slab connection and floor slab misalignment just by tightening one single bolt.