Introduction to Bridges
7.
BRIDGE PROBLEMS
APPROACH ROAD
1. Horizontal & vertical alignment
 Approach railing in accordance with standard drawing
 Signing in accordance with standard drawing
2. Approach bump
 fill settlement
 soil instability
 affects loading on bridge & level of service
3. Oil on pavement
 bump can cause danger and serious damage
4. Headslope Movement (Smoky River Hwy 34)
 bridge slide area fill moving to front & right relative to bridge
 movements can be sudden & destructive
JOINTS
5. Cover plated deck joint (gland type)
 headslope movement can cause problems with joints
 jammed up (no movement)
 bolts missing & hazard to traffic
 caused by poor plate fit (weld distortion)
 damage to pavement causing roughness
6. Finger Plate Joint
 right side fingers rotated up so snowplow guards required
 deteriorated concrete headers
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Introduction to Bridges
RAILING
7. Broken Railing Anchor
 almost always accident damage
 most common railing problem
 safety issue
8. Rail and Post Damage (Blindman River)
 serious condition - affects road user safety requires immediate
attention
DECKS
9. Deck Punch Out
 caused by large concentrated loads such as sheep foot packer or ice
lugs on cat tracks etc.
 hole on topside small and doesn’t seem serious
10. Punch Out on Underside
 large area of damage in a conical shape
 serious problem, immediate attention
11. Deck Sagging (Athabasca River Hwy 43)
 ponding water is an indication
 may not be serious; creep, should add deck drains
 or may be serious; girder damage, highload, etc.
12. Deck Cracks & Potholes
 these cracks due to failed shear connections between girders
 wearing surface rough
 load sharing of girders affected
CURBS
13. Hole In Curb
 usually caused by snowplows
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Introduction to Bridges
 fill up with water and freeze
 freezing can cause further damage
 should be reported for repair before winter
14. Snow Ramped Up On Curb
 what is the problem in this photo?
 curbs & rails designed as participating system
 snow will cause vehicles to vault and not act as designed
 snow & salt mix also increases deterioration rate
15. Deteriorated Curb & Rail
 salt action causes concrete deterioration
 emphasized by lack of proper air entrainment
 also accelerates steel corrosion
 paint on railing damaged by abrasion of road sanding
 posts and railing all galvanized now
GIRDERS & STRINGERS & TRUSSES
16. High Load Damage (Hwy 2 & 39)
 serious damage
 girder has no load carrying capacity left
 requires immediate action (barricade adjacent shoulder or lane)
 notice the incredible flexibility of steel
 this one not repairable
17. Broken Bottom Flange
 serious damage, immediate action
 has no load carrying capacity and needs bottom flange replaced
18. Damaged Prestressed Girder (Hwy 16 & Century Rd.)
 girder has broken strand
 even minor damage can seriously reduce load capacity if strand
broken
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Introduction to Bridges
19. Prestressed Type FC Girder Bridge with Destroyed Outside Leg (Hwy 16
& Hinton)
 Girder was repaired
 Fully serviceable
20. Spalled Concrete on Bottom Flange of Concrete Girder
 common problem on short span reinforced concrete girders
 caused by salt water getting through joint between girders
 perform quite well on local roads
 can still function provided rebar x-section not reduced
21. Cracked Timber Stringer
 typical flexural bending failure
 crack usually will be initiated by flaw or discontinuity in wood
 great variation in strength of timber members
22. Horizontal Misalignment of Girders
 curbs have shifted showing that spans have horizontal misalignment
 on skewed bridges this is caused by excessive abut back wall pressure
causes
 this can happen quickly
 minor movement is not serious
23. Bent Truss Vertical Member
 usually caused by wide load
 member deformations can cause cracks
 cracks often difficult to defect by eye(use ultrasonic)
 seriously reduces load capacity in compression members
 report damage
24. Collapsed Truss (Willow Creek Stavely)
 caused by overload on posted bridge
 well servicing rig tanker
25. Broken Truss Batter Post (Smokey River)
 very serious, bridge may collapse
 caused by dozer blade on cat being hauled by Municipality
 truss should have collapsed
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Introduction to Bridges
 saved by joint & member redundancy
BEARINGS
26. Broken Bearings
 roller nest with broken and displace roller
 usually found under trusses rather than girders
27. Displaced Neoprene Pad
 neoprene pad is walking out (happens over time)
 serious problem if allowed to progress
 most reliable trouble free type of bearing
 bearing surfaces must be parallel
 girder creep can change this
28. Eroded Abutment (Boulder Creek Hwy 33)
 headslope completely eroded with piles exposed
 emergency situation
29. Undermined Roadway (Battle River Hwy 2A)
 collapse very sudden
 high water can erode underneath leaving pavement intact
 very dangerous
 RCMP first on scene in this instance
30. Rotated Abutment (Paddle River)
 caused by soil instability slide
 girders jammed tight to backwall
 piles move forward rotating abutment in counter clockwise direction
31. Settled Pile
 pile no longer supporting abutment cap
 pile not driven to proper bearing capacity
 uniform settlement not as serious, can be tolerated (simple spans)
32. Rotten Abutment Cap
 first sign is a bulging of sides
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Introduction to Bridges
 outside is protected by treatment, inside not
 fungi can enter through untreated ends or through checks
 girders connected to cap with drift pins,
these also break the protective shell
33. Fill Settlement (Assineau River Hwy 2)
 fill settlement can cause cavity under abutment seat
 cavity can extend under roadway in time
 leads to bump at end of bridge, etc.
 caused by fill consolidation over time or erosion at toe of slope or by
erosion from water entering on approach at end of the bridge
PIERS
34. Pier Shaft Deterioration (Swan River Hwy 2)
 caused by salt water coming through deck joint
 steel corrodes and spalls concrete
35. Pier Cap Deterioration
 caused by salt water through joint
 poor quality layer of concrete cast on top of cap to correct elevation
36. Pier Erosion (Wapiti River)
 shaft pier on footing with piles
 flood destroyed slope protection then undermined pier
37. Pier Erosion
 about 3 m of piling exposed
 pier not damaged otherwise
 if only spread footing under the pier the bridge would have failed
38. Rotten Pier Cap
 cap is bulged and checked
 cap is crushing around pile
 very serious & dangerous condition
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Introduction to Bridges
39. Failed Pier Cap
 failure usually sudden without warning
 can lead to fatalities or serious damage
40. Vehicle Remains
 truck was hauling cat on a lowboy from road construction project up
the road
 bridge had been inspected and bulging had been reported
 seriousness of condition was not recognized and not repaired
41. Unstable Pier
 leaning due to shifting soil
42. Unstable Pier (Paddle River)
 pier leaning and moved longitudinally to left
 caused by massive slide
 pier cap was extended to pick up bearing
CULVERT
43. Cracked Seam
 longitudinal sidewall seam is cracked
 caused by inadequate backfill compaction and/or poor quality
backfill material
 must be well graded granular compacted to 95% - 100% Proctor
44. Cracked and Corroded Culvert
 corrosion here is on soil side
 rust stains coming through cracks in SPCSP
 rust will perforate culvert wall
45. Corroded Culvert
 waterside corrosion
 abrasion will wear away galvanizing
 some streams with effluent can be very corrosive
 culvert downstream of Vulcan potato chip plant for instance
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Introduction to Bridges
46. Deformed Culvert Floor
 more common in arch shaped culverts
 roof deformation in long spans most common
 this shape is not used any more
47. Sidewall Deformation
 culvert has failed
 usually roof will come down and sidewall will move outward
 winter installations with frozen material will fail
 proper compaction is essential!
48. Inlet Uplift
 high flow leads to differential in head at inlet
 inlet starts to float and culvert fails
 end treatment, shoulders, headwall and cut-off wall resist the uplift
CHANNELS
49. Hanging Outlet
 caused by streambed degradation
 most common in tributaries to major streams
 high velocity and erosion at outlet promotes it as well
50. Drift At Inlet (Whitecourt Creek)
 drift reduces flow area and capacity
 can plug culverts completely
 note elevation of high water as shown by location of highest drift
51. Drift At Bridge
 drift reduces flow area
 bridge opening must be wide enough and high enough (freeboard) to
ensure drift passes through
52. Roadway Failing Over Concrete Arch Culvert
 culvert failure is allowing roadway to erode
 water starting flow into hole on shoulder of road
 material from outside of culvert already gone
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Introduction to Bridges
53. Washout
 roadway washed out
 depth of flow, culvert not visible
 flexbeam guardrail OK
54. Washout
 remains of culvert after water receded
 washout initiated by failure of concrete floor in culvert
 once floor gone footing support quickly eroded
 replacement cost approximately $1 million
55. Beaver Dam
 dams impede flow through structures
 culverts can be plugged completely
56. Salted Bridge
 salt coating on railing and curb very evident
 this is typical for most major bridges in the spring
 wetting and drying of concrete carries chloride ions into concrete
 chloride ion is good electrolyte so ideal for promoting corrosion
57. Duffy
 Duffy says “Guess I should have washed off the road salt.”
 simple and effective maintenance for bridge structures
 this can prevent or mitigate many of the problems that were
illustrated and increase the life of bridges
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