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Findings from On-site Inspection ( Rt 202/US Rt 23 BRIDGE ) On Tuesday, June 14 Masato Matsumoto Executive Vice President NEXCO-West USA, Inc.

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Presentation on theme: "Findings from On-site Inspection ( Rt 202/US Rt 23 BRIDGE ) On Tuesday, June 14 Masato Matsumoto Executive Vice President NEXCO-West USA, Inc."— Presentation transcript:

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.

2 West NEXCO Central NEXCO East NEXCO Metropolitan EXPWY Co. Hanshin EXPWY Co. Japan Bridge Co. Expressways in Japan 2 NEXCO group Total (a of March 2006) Service Length8,286km Bridge Length 1,250km ( 15% ) # of Bridges13,400

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 3

4 Deteriorated Bridges in Japan 4 Fatigue of RC Deck SlabChloride Induced Deterioration

5 Highway Inspection (NEXCO Toll Roads) Contract Routine InspectionMaintenance Contractor (Group Company) Detail InspectionEngineering Company (Group Company) Inspection TypeFrequency Routine InspectionOn-vehicle Inspection : 2 to 3 times per week Walking Inspection : at least twice a year Detail InspectionEvery 5 years Note: Frequency Depends on Traffic Volume 5

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

7 Detail Inspection (Visual Inspection)7

8 Definition of Bridge Condition Condition State Description AACritical condition. Should be repaired as soon as possible. A A1Poor condition. Should be repaired within 2 years. A2Poor condition. Should be repaired within 5 years. A3Poor condition. Repair work is not required within 5 years. Monitoring is required. BFair Condition. Should be monitored. OKGood or Excellent Condition. Note: If the damage can cause hazards to traffic or third party, additional ‘E’ is attached to the condition states. Condition State Description 0Failed 1Imminent Failure 2Critical 3Serious 4Poor 5Fair 6Satisfactory 7Good 8Very good 9Excellent NEXCO US (NBIS) 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 11 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

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

13 Notes from Visual Inspection 13

14 Recommendations (Crack in P1) ①-1 ①-2②-1 Condition State 【 A1 】 14 W:1.20m x L:0.20m P1 Lateral Beam Rebar Exposure W:0.70m x L:0.20m P1 Lateral Beam Rebar Exposure

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

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 Sound Concrete Spalled Area ⑤-1 ⑤-2 ⑤-3 Condition State 【 A1 】 18 W:0.80m x L:0.20m Overhang Slab

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

21 25000 pix 4000 pix 100 millon pix 460 MB/TIF 1pix=1mm 0.5mm crack can be identified. Crack Detection by Image Processing Technology Rt 202/US Rt 23 BRIDGE 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 Railway 25

26 26 Results of Infrared Technology P46P47 KEY WEST MIAMI Ocean side Gulf side Repaired Area Re-deterioration (Drain Hole)

27 Thank you for your attention


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