This project is to replace the floor slab of Konikuma Bridge, located between Azumino IC and Asai IC on the Nagano Expressway, which has been open for 23 years.
The cause of the deterioration of the floor slabs is thought to be that minute cracks occur due to increased wheel loads due to larger vehicles, and salt contained in the antifreeze sprayed in winter seeps into the interior of the floor slabs, causing deterioration.
Precast PC floor slabs were used for the floor slab format, and the process from removing the slab to installing a new slab took 30 days (removal during the day and laying at night), shortening the construction period.