Current Status of Japanese Road Bridges and Future Perspective HIROAKI TERAMOTO Ministry of Land, Infrastructure and Transport
Mar 31, 2015
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)
Classification Total
Steel bridges
RC bridges PC bridges Others
National expressways 6,510 1,977 1,941 2,284 308 National highways 22,542 10,719 3,161 8,027 635 Prefectural roads 31,361 12,310 6,064 12,196 791 Municipal roads 82,108 31,130 14,536 32,715 3,727 Total 142,521
(100%) 56,136 (39%)
25,702 (18%)
55,222 (39%)
5,461 (4%)
Distribution of bridges for completion year
0
5,000
10,000
15,000
20,000
25,000
30,00019
26~
30
1931
~35
1936
~40
1941
~45
1946
~50
1951
~55
1956
~60
1961
~65
1966
~70
1971
~75
1976
~80
1981
~85
1986
~90
1991
~95
1996
~20
00
The others
PC bridges
RC bridges
Steel bridges
Num
ber
of b
ridg
es
0
5,000
10,000
15,000
20,000
25,000
30,00019
26~
30
1931
~35
1936
~40
1941
~45
1946
~50
1951
~55
1956
~60
1961
~65
1966
~70
1971
~75
1976
~80
1981
~85
1986
~90
1991
~95
1996
~20
00
The others
PC bridges
RC bridges
Steel bridges
Num
ber
of b
ridg
es
Road Work Budget in JAPAN (2005)
Total investment
in road projects in JAPAN
£ 50.96 billion (100%)
National Road Projects
£ 11.47 billion (22.5%)
Projects undertaken by local governments
£ 30.65 billion (60.1%)
Operation of Toll Roads
£ 8.84 billion
(17.4%)
Maintenance
& repair
£ 1.44 billion
Construction, operation & others
National Highways Maintenance Budget(2005)
Maintenance and Repair (£ 1.44Billion)
Maintenance
£ 1.10 Billion
( 77 %)
Improvement
£ 0.33 Billion
(23%)
Repair work for Structure: (35%)
Repair of bridges and tunnels, Pavement
Daily Maintenance : (13%)
Road cleaning, Planting etc.
Road Patrol : (9%)
Minor Repair Work : (18%) Repair for retaining walls, drains etc.
Others : (2 %)
Emergency restoration for disasters
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)
Damage level Description Percentage(%)
A There is no damage, or damage is so little that there is no need for
repair. 5.9
B Repair may be necessary depending on the condition. 81.4
C Prompt repair or other remedial action is required. 12.8
E Emergency measures must be taken. 0.0
Total 100.0
Damaged gas pressure weld point (main reinforcements)
Breaking at corner of the shear reinforcement
Breaking of reinforcing bars by ASR
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 andpeeling of concrete50.0%
The others 6.8%
Damage ofRC slab
67.2%
Corrosion of steel member26.0%
Air Salt in Winter (climate)
Tsukuba
Narita Airport
Tokyo
Kansai AirportOsaka
Kyoto
Tokyo to Tsukuba 50kmTokyo to Osaka 560km
N
S
MonsoonRome
latitude
Maintenance cost for a deteriorated concrete bridge
A Bridge
0
100
200
300
0 10 20 30 40
Age (year)
Sum
of
cost
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.
Case 1 : Preventive repair (Minimizing Life Cycle Cost)Case 2: Repair at the repairable limit state
T₁ T₂ T₃
yearEvaluation
period
Cost
Case 1
Case 2
T₁ T₂ T₃
yearEvaluation
period
Soundness
Smallrepair
Smallrepair
Largerepair
Case 1
Case 2
Relation between type of repairs and cost
Bridge DimensionsInspection
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
Asset Management Flow of Bridges Maintenance
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