bridge maintenance and repair. bridge maintenance and repair technical standards branch introduction...

Bridge Maintenanceand Repair

BRIDGE MAINTENANCE AND REPAIR

TECHNICAL STANDARDS BRANCHINTRODUCTION TO BRIDGES

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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



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Slide 3

PREVENTATIVEMAINTENANCE

ISCOST EFFECTIVE!



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Slide 4

General Methods - Concrete

• removal and replacement of deteriorated concrete

• filling cracks

• coating and sealing concrete surface



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Slide 5

General Methods - Steel

• protect it from exposure to electrolytes

• painting

• galvanizing



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Slide 6

General Methods - Timber

• control moisture content of the wood



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Slide 7

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”)



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Slide 8

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



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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



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Slide 10

Substructure - Concerns (cont’d)

• Impact damage

• Other damage– pressure exerted on the piers and abutments by the

earth



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Slide 11

Substructure - Maintenance

• Material deterioration– protective coatings– preservatives

• Foundation settlement and earth pressure– subsurface drains– struts– regrading soil profile



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Slide 12

Substructure - Maintenance (cont’d)

• Impact damage– guard rails and energy dissipaters– fenders or steel plates on abutments and piers



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Slide 13

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



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Slide 14

Superstructure - Maintenance

• Inspection

• Good protection system– coatings - preservatives– sealers - patching– paints - crack filling

• Pressure washing and cleaning

• Strengthening



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Slide 15

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



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Slide 16

Concrete Decks

• De-icing salt is main menace– causes reinforcement to corrode– concrete spalls– potholes



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Slide 17

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



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Slide 18

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



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Slide 19

Curbs & Railings

• Deteriorate with time– cracking and spalling - corrosion– salt damage - collision

• Replacement can be minimized– appropriate sealers, coatings and paint– galvanized steel



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Slide 20

Deck Drains

• Can cause hazardous traffic situations

• Can lead to deterioration of deck and other bridge elements and erode the soil backfill



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Slide 21

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



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Slide 22

Approach Road

• Approach bump

• Guardrail– connection to bridge rail– transition stiffness

(standard drawing S-1471 & S-1472)

• Drainage– trough drains



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Slide 23

Approach Road (cont’d)

• Erosion of headslopes and ditches

• Signing– vertical clearance– load limit– delineators



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Slide 24

Streams and Channels

• Erosion control

• Slope protection

• Bank protection

• Rip-rap

• Drift

• Beaver dams



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Slide 25

Bridge Major Maintenance and Rehabilitation

• Total deck replacement

• Partial-depth deck replacement

• Delamination repair

• Deck overlays

• Cathodic protection

• Deck joint replacement

• Bearing replacement



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Slide 26

Culvert Major Maintenance and Rehabilitation

• Strutting

• Culvert liners

• Culvert end treatment repair and replacement

• Cathodic protection



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Slide 27

Repair Materials

• Concrete– silica-fume concrete– fibre reinforced concrete– latex modified concrete– corrosion-inhibiting concretes



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Slide 28

Repair Materials (cont’d)

• Polymers– polymer concretes– polymer overlays

• Specialty products– patching materials– grouts– sealers



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Slide 29

Approved Products

• Standard testing procedures

• Certified laboratories

• Testing paid by manufacturer

• Approved products list– concrete sealers– concrete patching & grouting– paints



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Slide 30

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%



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Slide 31

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



TRANSPORTATION

Slide 32

Paints• Type B2

– Truss / River / Little experience

• Type B3– Girder / River / Much experience

• Type B5 & B6– Freeway / Overpass

• Type 8– Submerged pipe piles

bridge maintenance and repair. bridge maintenance and repair technical standards branch introduction...

Documents

repair slide

bridge maintenance

bridges transportation

life of bridge slide

earth slide

wood slide

galvanizing slide

concrete surface slide