Measures for Deteriorated Roads

The average age of national highway bridges in Fukuoka is 45 years

Out of 307 km of national highways which Fukuoka National Highways manages, 7% consist of bridges, 1% of tunnels and 92% of earthen structures.

Regarding bridges, approximately 39% of them are over 50 years old; the average age of them is 45 years.

Moreover, the proportion over 50 years old will sharply increase to 55% in 10 years, and 70% in 20 years.

25% of bridges need urgent repair

For road structures such as bridges, to find damage due to aging at an early stage, periodic visual inspections are conducted every five years.
(The first inspection for newly built bridges is conducted within two years after commencement of use).

Depending on the state of disrepair, we categoriseinspection results into nine grades for taking measures. Regarding the bridges of Fukuoka National Highways, approximately 25% of them are classified as "C (C1, C2 inclusive)," which means that they need prompt repair.

Secure Maintenance Cycle Implementation

Responding to the SasagoTunnel Ceiling Slab Fall Incident, the Ministry of Land, Infrastructure and Transport (MLIT) declared “The Inaugural Year of Maintenance” in 2013 and took actions such as full inspection of stock and legalisationof inspection standards through the Road Law reform. Then, to introduce the maintenance cycle on a full scale (inspection, diagnosis, measure implementation, record taking), MLIT declared “the year of maintenance execution” in 2014 to determine the maintenance cycle (clarification of the obligation of the road administrator) and create a mechanism to carry out the maintenance cycle (establishment of road maintenance committee and so forth).

We regularly promote periodic inspections of bridges, tunnels, and so on by adhering to close visual checks every five years as well as to take measures systematically based on investigations.

Update：March 22,2018