1. Findings from On-site Inspection (Rt 202/US Rt 23 BRIDGE)
On Tuesday, June 14
Masato Matsumoto Executive Vice President
NEXCO-West　USA, Inc.
Good morning, Everyone. My name is Masato Matsumoto, from the Japanese highway agency (NEXCO).

2. Expressways in Japan Service Length 8,286km Bridge Length 1,250km（15%）
NEXCO group Total (a of March 2006)
Service Length
8,286km
Bridge Length
1,250km（15%）
# of Bridges
13,400
East
NEXCO
Central NEXCO
West
NEXCO
This is the map of Japan.
There are three intercity expressway companies in Japan, East, Central and Wet NECXOs, and Metropolitan Expressway company, Hanshin Expressway Company, and Japan Bridge.
The total length of expressways owned by NEXCO group are 8,286km, and about 15% of them are bridges.
And # of Bridges is about 13,400.
Metropolitan EXPWY Co.
Japan Bridge Co.
Hanshin EXPWY Co. 2 2

3. Deterioration of Concrete Structures in Japan
【Environmental factors】
- Chloride induced deterioration
- Carbonation
【External forces (e.g. traffic load)】
- Fatigue for reinforced
　concrete deck slabs
- Fatigue for steel bridges
This slide shows some examples of deterioration mechanisms of concrete structures.
Generally speaking, concrete structures deteriorate from Environmental factors and External forces.
This is an example of a concrete bridge girder deteriorated by chloride induced deterioration.
The other major factor of deterioration is carbonation.
For external forces, we have fatigue for reinforced concrete deck slabs and also fatigue for steel bridges. 3 3

4. Deteriorated Bridges in Japan
These are some examples for condition evaluation.
This figure shows an example of structures suffered by chloride induced deterioration.
According to the visual inspection result, this has been categorized somewhere between State II And State III.
This on is an example of RC deck slab deteriorated by fatigue due to the wheel load.
According to the visual inspection result, this has been categorized as State II.
Chloride Induced Deterioration
Fatigue of RC Deck Slab 4 4

5. Highway Inspection (NEXCO Toll Roads)
Inspection Type
Frequency
Routine Inspection
On-vehicle Inspection : 2 to 3 times per week
Walking Inspection : at least twice a year
Detail Inspection
Every 5 years
Note: Frequency Depends on Traffic Volume
Contract
Routine Inspection
Maintenance Contractor (Group Company)
Detail Inspection
Engineering Company (Group Company) 5

6. Routine Inspection (on foot)
Routine Inspection (from the vehicle)
Routine Inspection (on foot) 6

7. Detail Inspection (Visual Inspection)7

8. Definition of Bridge Condition
NEXCO
US (NBIS)
Condition State
Description AA
Critical condition. Should be repaired as soon as possible. A A1
Poor condition. Should be repaired within 2 years. A2
Poor condition. Should be repaired within 5 years. A3
Poor condition. Repair work is not required within 5 years. Monitoring is required. B
Fair Condition. Should be monitored. OK
Good or Excellent Condition.
Condition State
Description
Failed 1
Imminent Failure 2
Critical 3
Serious 4
Poor 5
Fair 6
Satisfactory 7
Good 8
Very good 9
Excellent
Note: If the damage can cause hazards to traffic or third party,
additional ‘E’ is attached to the condition states. 8

9. Typical Damage to be Detected
Steel Bridges
1. Unusual Deformation
2. Unusual Sound
3. Unusual Vibration
4. Deterioration in Paint Systems
5. Corrosion of the Steel Members
6. Rivet or High Tension Bolts
7. Cracks in Steel Members
8. Deformation or Buckling due to Collision or Earthquake
9. Water Leakage 9

10. Typical Damage to be Detected
Concrete Bridges
1. Unusual Deformation of Girders and Slabs
2. Unusual Sound
3. Unusual Vibration
4. Unusual Expansion Joint Movement
5. Unequal Displacement of Bearings
6. Rotation or Movement of Pier or Abutment
7. Cracking in Concrete
8. Water Leakage
9. Free Lime
10. Delamination or Spalling of Concrete
11. Rebar Exposure
12. Rust Exudation
13. Unusual Color due to Chemical Effect
14. Rebar Corrosion
15. Corrosion or Failure of PC Strand 10

11. Notes from Visual Inspection
W:1.50m x L:0.10m Lower Flange
Decline of Steel Bearing
Displacement - B
Decline of Steel Bearing Touching the Stopper
2 Loose Bolts for Steel Bearing
Displacement – A3 11

12. Notes from Visual Inspection
Bridge Name, Location, etc.
Damage Description
Date
Weather
Inspector
etc.
Area
Damage Location
Condition State
Recommendation
Counter Action
Repaired Date 12

13. Notes from Visual Inspection13

14. Recommendations (Crack in P1)
Condition State　【A1】
W:1.20m x L:0.20m P1 Lateral Beam Rebar Exposure
W:0.70m x L:0.20m P1 Lateral Beam Rebar Exposure
①－１
Condition State　【A1】 14
②－１
①－２

15. Recommendations (Bearings on P2)
Condition State　【B】
Displacement - B
Decline of Steel Bearing
Decline of Steel Bearing, Touching Stopper
③-1
Condition State　【A3】
④-1 15
④-2

16. Recommendations (Bearings on P2)
The movable bearing has the functionality of moving and rotation. There are stoppers near the movable bearing to restrict the movement.
The above stoppers has been in the compressed status.
Counteraction should be considered if the displacement is active. 16

17. Recommendations (Spalling over P2)17

18. Recommendations (Spalling over P2)
Condition State　【A1】
W:0.80m x L:0.20m Overhang Slab
⑤－１
Sound Concrete
Spalled Area 18
⑤－２
⑤－３

19. Recommendations (Spalling over P2)
Rebar corrosion at the end of the slab concrete, due to the water leakage from expansion joint.
Waterproof of expansion joint is recommended.
Anticorrosive countermeasures for rebar and replacement of the cover concrete should be scheduled. 19

20. Recommendations (Delamination)
Condition State　【A2】
W:0.30m x L:0.20m
⑥－１
Condition State　【A1】
W:1.80m x L:0.30m 20
⑦－１

21. Crack Detection by Image Processing Technology
Rt 202/US Rt 23 BRIDGE
1pix=1mm
0.5mm crack can be
identified.
100 millon pix 460 MB/TIF
25000 pix
4000 pix 21

22. ・Recognize the crack by Photoshop CS4.
・The crack width can be identified using special" crack detection engine".
・Crack width is detected approximately based on the width corresponding to 1 pix
in the photos.
Width legend　 －－： <0.5mm
－－： 0.5mm～0.7mm
－－： >0.7mm 22

23. 0.2mm
1.4mm
1.6mm
800mm
Image of the crack in Abutment A1; Photos taken from 22 meters away; The practical resolution can be expected to reach 0.1mm/pix. 23

24. 24

25. Overhang Deck over Railway25

26. Results of Infrared Technology
Re-deterioration
Repaired Area
(Drain Hole)
(Drain Hole)
KEY WEST
MIAMI
P46
P47
This is an example from the concrete barrier.
We can see repaired area here, and our damage classification system have found the re-delamination for repaired concrete.
Gulf　side
Ocean　side

27. Thank you for your attention