Bridge Maintenance and Repair
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Transcript of Bridge Maintenance and Repair
Bridge Maintenanceand Repair
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
Slide 2
Preventative Maintenance Objectives
• Preserve investment- Cost of replacement higher than initial cost
- Repair costs increase with time
• Safety and avoidance of catastrophic failure
• Maximize life of bridge
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
Slide 3
PREVENTATIVEMAINTENANCE
ISCOST EFFECTIVE!
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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General Methods - Concrete
• removal and replacement of deteriorated concrete
• filling cracks
• coating and sealing concrete surface
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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General Methods - Steel
• protect it from exposure to electrolytes
• painting
• galvanizing
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
Slide 6
General Methods - Timber
• control moisture content of the wood
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Bridge Seats and Caps
• Runoff through deck joints contains debris and de-icing chemicals– de-icing chemicals that accumulate on substructure
cap can result in:• corrosion of reinforcing steel and spalling concrete
• corrosion of bearing assembly (i.e. “frozen bearing”)
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Bridge Seats and Caps (cont’d)
• Proper maintenance– regular cleaning of substructure caps and deck joints
with high pressure pump– provide drainage troughs below deck joints– surface protective coatings on bearing systems
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
Slide 9
Substructure - Concerns
• Material deterioration– wet/dry and freeze/thaw cycles– abrasion by water/ice at waterline– steel corrosion– concrete spalling– decay and vermin attack on timber
• Ground settlement
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
Slide 10
Substructure - Concerns (cont’d)
• Impact damage
• Other damage– pressure exerted on the piers and abutments by the
earth
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Substructure - Maintenance
• Material deterioration– protective coatings– preservatives
• Foundation settlement and earth pressure– subsurface drains– struts– regrading soil profile
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Substructure - Maintenance (cont’d)
• Impact damage– guard rails and energy dissipaters– fenders or steel plates on abutments and piers
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Superstructure - Concerns
• Usually very difficult to access, so problems are frequently overlooked
• Deterioration occurs with time– salt and chemicals - cracks in concrete– corrosion - frozen bearings– carbonation and sulfation
• Impact damage– high loads– ice and drift
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Superstructure - Maintenance
• Inspection
• Good protection system– coatings - preservatives– sealers - patching– paints - crack filling
• Pressure washing and cleaning
• Strengthening
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Deck
• Most susceptible to deterioration– de-icing salts, acid rain– ultraviolet rays– mechanical abrasion
• Requires a lot of maintenance and repair
• Protects rest of structure
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Concrete Decks
• De-icing salt is main menace– causes reinforcement to corrode– concrete spalls– potholes
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Concrete Decks (cont’d)
• Design and construction features to control deterioration– optimum cover for reinforcement– good drainage - silica fume– smaller skews - low w/c ratio– thicker slabs - good consolidation– air-entrained concrete - low shrinkage
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Concrete Decks (cont’d)
• Main preventative maintenance goal is to control salt and moisture penetration– keep deck clean and drains operating properly– add drains in low spots– monitor deck for chloride contamination– fill cracks– asphalt sealing– polymer overlays– concrete sealers– bituminous concrete overlays with waterproof
membrane
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Curbs & Railings
• Deteriorate with time– cracking and spalling - corrosion– salt damage - collision
• Replacement can be minimized– appropriate sealers, coatings and paint– galvanized steel
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Deck Drains
• Can cause hazardous traffic situations
• Can lead to deterioration of deck and other bridge elements and erode the soil backfill
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Deck Drains (cont’d)
• Typical problems include:– ponding of water on bridge deck– poor drainage allows de-icing salts to deposit
on deck and other bridge elements– plugged downspout will burst in freezing
weather
• Regular cleaning is best maintenance
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Approach Road
• Approach bump
• Guardrail– connection to bridge rail– transition stiffness
(standard drawing S-1471 & S-1472)
• Drainage– trough drains
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Approach Road (cont’d)
• Erosion of headslopes and ditches
• Signing– vertical clearance– load limit– delineators
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Streams and Channels
• Erosion control
• Slope protection
• Bank protection
• Rip-rap
• Drift
• Beaver dams
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Bridge Major Maintenance and Rehabilitation
• Total deck replacement
• Partial-depth deck replacement
• Delamination repair
• Deck overlays
• Cathodic protection
• Deck joint replacement
• Bearing replacement
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Culvert Major Maintenance and Rehabilitation
• Strutting
• Culvert liners
• Culvert end treatment repair and replacement
• Cathodic protection
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Repair Materials
• Concrete– silica-fume concrete– fibre reinforced concrete– latex modified concrete– corrosion-inhibiting concretes
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Repair Materials (cont’d)
• Polymers– polymer concretes– polymer overlays
• Specialty products– patching materials– grouts– sealers
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Approved Products
• Standard testing procedures
• Certified laboratories
• Testing paid by manufacturer
• Approved products list– concrete sealers– concrete patching & grouting– paints
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Concrete Sealers
• Type 1a - relatively dry deck RMC < 55%
• Type 1b - outdoor exposure deck RMC < 70%
• Type 1c - outdoor exposure deck RMC < 80%
• Type 2a - one component coatingRMC < 70%
• Type 2b -two component coating RMC < 70%• Type 3 - pigmented coating RMC < 70%
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Concrete Patching Materials• Type NH
– poured horizontal patches, 3 day curing
• Type OH-V– trowelled overhead or vertical patch
• Type LTH– low temperature poured horizontal patch
• Type HEH– high early strength poured horizontal patch
BRIDGE MAINTENANCE AND REPAIR
TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES
TRANSPORTATION
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Paints• Type B2
– Truss / River / Little experience
• Type B3– Girder / River / Much experience
• Type B5 & B6– Freeway / Overpass
• Type 8– Submerged pipe piles