Current Status of Japanese Road Bridges and Future Perspective HIROAKI TERAMOTO Ministry of Land, Infrastructure and Transport

Numbers of bridges by type of material (only bridges over 15m)

Distribution of bridges for completion year

Road Work Budget in JAPAN (2005) Maintenance & repair ￡1.44 billion National Road Projects ￡11.47 billion (22.5%) Construction, operation & others Total investment in road projects in JAPAN ￡50.96 billion (100%) Projects undertaken by local governments ￡30.65 billion (60.1%) Operation of Toll Roads ￡　8.84　billion (17.4%)

National Highways Maintenance Budget(2005) Repair work for Structure: (35%) Repair of bridges and tunnels, Pavement Daily Maintenance : (13%) Road cleaning, Planting etc. Maintenance ￡1.10 Billion ( 77 %) Road Patrol : (9%) Minor Repair Work : (18%) Repair for retaining walls, drains etc. Maintenance and Repair (￡1.44Billion) Others : (2 %) Emergency restoration for disasters Improvement ￡0.33 Billion (23%) Countermeasures for earthquakes : (11%) Reinforcing of substructures, Prevention for bridge fall Disaster prevention : (12%) Slope protection

Type of Inspection in JAPAN Usual Inspection Periodic Inspection Special Inspection （Salt Damage, ASR, Fatigue…） Disaster Inspection ( Earthquake, typhoon…)

Damage of Road Bridges in JAPAN (the Results of Periodic Inspection)

Fatigue cracks on girder

Breaking of reinforcing bars by ASR Damaged gas pressure weld point (main reinforcements) Breaking at corner of the shear reinforcement

Dropping-off of concrete of RC Slab

Causes for bridge reconstruction (National highways and prefectural roads)   Steel bridges PC bridges Cracking and peeling of concrete (Chloride attack) 16.7% Damage of RC slab 33.3% Cracking and peeling of concrete 50.0% The　others 6.8% Damage of RC slab 67.2% Corrosion of　steel member 26.0%

Chloride damage of PC girder

Air Salt in Winter (climate) Tsukuba Narita Airport Tokyo Kansai Airport Osaka Kyoto Tokyo to Tsukuba 50km Tokyo to Osaka 560km N S Monsoon Rome latitude

Maintenance cost for a deteriorated concrete bridge

Prediction by the results of Inspection (example) Chloride Damage in concrete at cover depth If Cl- exceeds 1.2kg/m3 or will exceed 1.2kg/m3 within next 10 years, Planning of Repair should be undertaken.

Relation between type of repairs and cost Case 1：Preventive repair (Minimizing Life Cycle Cost) Case 2：Repair at the repairable limit state T₁ T₂ T₃ year Evaluation period Cost Case 1 Case 2 Soundness Small repair Large

Asset Management Flow of Bridges Maintenance Bridge Dimensions Inspection Properties of structure Database Prediction of Future Soundness Comparison of Type of Measures,Minimizing of Life Cycle Cost,　Budget Restriction / Social Situation Investment Analyzing Risk based Prioritization Decision of Management Plan Execution of Measures or Maintenance Evaluation of Present Soundness

SUMMARY ( Needs in JAPAN) (1) Inspection of Local Road Bridges ( needs to make a New Act/Law) (2) Improve the Forecast Model of Deterioration ( the Methods of Life Cycle Cost Analysis ) (3) Develop Non-Destructive Test Techniques (4) Develop Prioritization System of Maintenance (5) Make the Market of Maintenance-Works more Attractive and Profitable

Thank you for your attention! END