1. Bridge Maintenance
and Repair

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

3. PREVENTATIVE MAINTENANCE IS COST EFFECTIVE!

4. General Methods - Concrete
removal and replacement of deteriorated concrete
filling cracks
coating and sealing concrete surface

5. General Methods - Steel
protect it from exposure to electrolytes
painting
galvanizing

6. General Methods - Timber
control moisture content of the wood

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”)

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

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

10. Substructure - Concerns (cont’d)
Impact damage
Other damage
pressure exerted on the piers and abutments by the earth

11. Substructure - Maintenance
Material deterioration
protective coatings
preservatives
Foundation settlement and earth pressure
subsurface drains
struts
regrading soil profile

12. Substructure - Maintenance (cont’d)
Impact damage
guard rails and energy dissipaters
fenders or steel plates on abutments and piers

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

14. Superstructure - Maintenance
Inspection
Good protection system
coatings - preservatives
sealers - patching
paints - crack filling
Pressure washing and cleaning
Strengthening

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

16. Concrete Decks De-icing salt is main menace
causes reinforcement to corrode
concrete spalls
potholes

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

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

19. Curbs & Railings Deteriorate with time Replacement can be minimized
cracking and spalling - corrosion
salt damage - collision
Replacement can be minimized
appropriate sealers, coatings and paint
galvanized steel

20. Deck Drains Can cause hazardous traffic situations
Can lead to deterioration of deck and other bridge elements and erode the soil backfill

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

22. Approach Road Approach bump Guardrail Drainage
connection to bridge rail
transition stiffness
(standard drawing S-1471 & S-1472)
Drainage
trough drains

23. Approach Road (cont’d)
Erosion of headslopes and ditches
Signing
vertical clearance
load limit
delineators

24. Streams and Channels Erosion control Slope protection Bank protection
Rip-rap
Drift
Beaver dams

25. Bridge Major Maintenance and Rehabilitation
Total deck replacement
Partial-depth deck replacement
Delamination repair
Deck overlays
Cathodic protection
Deck joint replacement
Bearing replacement

26. Culvert Major Maintenance and Rehabilitation
Strutting
Culvert liners
Culvert end treatment repair and replacement
Cathodic protection

27. Repair Materials Concrete silica-fume concrete
fibre reinforced concrete
latex modified concrete
corrosion-inhibiting concretes

28. Repair Materials (cont’d)
Polymers
polymer concretes
polymer overlays
Specialty products
patching materials
grouts
sealers

29. Approved Products Standard testing procedures Certified laboratories
Testing paid by manufacturer
Approved products list
concrete sealers
concrete patching & grouting
paints

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 coating RMC < 70%
Type 2b -two component coating RMC < 70%
Type 3 - pigmented coating RMC < 70%

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

32. Paints Type B2 Type B3 Type B5 & B6 Type 8
Truss / River / Little experience
Type B3
Girder / River / Much experience
Type B5 & B6
Freeway / Overpass
Type 8
Submerged pipe piles