Complete Description of practice suggested by the government of India for bridge Inspection and maintenance.

1. Assessment and Management
of Bridges in India
Khyati Saggu
Assistant Professor
Department of Civil, PIET

2. Thomas B. Macaulay once said “ Of all the inventions, the alphabets
and the printing press alone excepted, those inventions which abridge
distance have done the most for the civilization of our species

3. Brief Introduction
Bridge is the structure providing the passage over an
obstacle without closing the way beneath.
These are the epitome of beauty, connectivity and also
the connectivity of any nation.
Arch bridges, cantilever bridges, suspension bridges,
truss bridges, beam bridges are the prominent
structures widely seen In India.
Though these are the integral structures standing tall and
facilitating movement, but when viewed closely we witness
serious issues left unaddressed from years.

4. These defects in bridges may lead to its fall or
impairment that might cause catastrophic condition
for nation

5. These scenarios are frequent in India and the only solution to avoid
future encounter with such situations is
PROPER INSPECTION AND MAINTAINENCE OF BRIDGES

6. Purpose of Inspection
Ensure structural stability
Identify potential risk
Periodical and systematically Record of
behaviour
Ensuring restrictions

7. Planning Inspection
Decide the number of bridges for
inspection
Study the previous reports of the bridges/
Preliminary study
Prepare proper plan for the important
bridges
Plan special equipment for the inspection

8. Scheduling Inspection
 Scheduling is prescribed in Indian Railways Bridge
Manual (IRBM)
 As per recommendations, all the bridges are to be
inspected by PWIs/IOWs once a year before monsoon
and by AENs once a year after monsoon, and important
bridges by DENs once a year
 All the steel structures are inspected by BRIs once in 5
years and selected bridges by Bridge Engineers/Dy.CE
(Bridges) as and when found necessary
 Bridges which are overstressed should be inspected
more frequently as laid down vide para 509 of IRBM.

9. Scheduled Inspection form

10. Bridge
Inspection
Equipment

11. Arrangement for Inspection of Bridge
Superstructure
 Chequered plate arrangement for key man
walkway (A)
Pathway for inspection from side of the bridge (B)
Ladder is added to end frame to reach up of
through only (C)
Arrangement for inspection on top chord (D)
Cradle arrangement for bridge inspection (E)

12. (A)
(B)
(C)
(D)
(E)

13. Mobile Bridge Inspection Unit
Self propelled vehicle for inspection of bridge
members which not accessible with the present
system used in railway bridges
Speed -50 Km/hr, 6 workmen for inspection
Suitable for Open deck steel plate girder bridges.
Ballasted deck bridges ,Arch bridges, Via ducts
and piers and abutments of bridge
The MBIU consists of 2 units: Power Pack vehicle
& Inspection vehicle

14. The inspection vehicle is equipped with:
1. Bucket type unit -
2. Main platform type unit
3. Hoist type platform unit capable of descending 100 m
below the rail level of access for inspection along bridge
piers / abutments

15. Detailed
Inspection of
Bridges

16. Foundations
 Visual inspection of foundations
is difficult
 Foundation movements may
often be detected by first
looking for deviations from the
proper geometry of the bridge.
 Any abrupt change or kink in
the alignment of bridge may
indicate a lateral movement of
pier
 Inadequate or abnormal
clearance between the ballast
wall and end girders are
indications of probable
movement Caisson Foundation

17. Major issues with foundations
Disintegration of foundation material
The dried exposed portions can be easily probed to ascertain whether the
construction material is showing signs of deterioration or distress.
 Heavy localized scour in the vicinity of
piers/abutments
Scour is the erosive action of running water in loosening and carrying
away material from the bed and banks of the river. Generally seen as
local, contraction and degradation scour
Uneven settlement
Existent due to difference in loading patterns and soil strata

18. Major issues with foundations
Crushing and cracking of masonry
Witnessed in bed blocks arises due to excessive dynamic impact or construction
material
Weathering
Areas of the bridge structure which undergo alternate drying and wetting are
prone to exhibit weathering damage
Failure of mortar
Lime mortar and cement mortar with free lime content are subject to leaching
because of action of rain and running water
Bulging
Bulging occurs in abutments, wing walls and parapet walls essentially on account
of excessive back pressure
Transverse cracks in piers
These cracks can arise because of increased longitudinal forces coming over the
pier and thereby creating tensile stresses in portions of the pier, correspondingly
redistributing a higher compressive force in compression zone

19. Local Scour Differential settlement
Cracks on pier Scour on shallow foundation
Uneven settlement
Bulging of pier

20. Protection Works
Protection works are appurtenances provided to
protect the bridge and its approaches from damage
during high flood conditions.
These generally includes:
Flooring
Curtain and drop walls
Pitching
Toe walls
Guide bunds
Marginal bunds
Spurs/ groynes
Aprons
Closure bunds
Assisted cut offs
Approach banks
Sausage/rectangular crates

21. Wire Crates
Guide bund and apronToe wall and pitching
Curtain wall, drop wall and flooring

22. Bearings
Inspection need to be done for the following:
 Oiling and greasing is required to be done once in 3 years
 Excessive longitudinal movements of the superstructure
result in shearing of location strips as well as anchor
bolts connecting the base plates.
 Gaps at certain location due to non uniform contact
between the bottom face of the bed plate and top
surface of the bed block that leads to its crushing.
 The rockers, pins and rollers should be free of corrosion
and debris that might lead to freeze condition.

23. Bearings in cont.
Inspection need to be done for the following:
 The tilt of segmental rollers should be measured with
respect to reference line and the temperature at the
time of measurement should also be noted.
 In case of roller bearings with oil baths, dust covers
should invariably be provided to keep the oil free
from dirt.
 Elastomeric bearing need to checked for Shear
deformation, rotation leading to off-loading of an
edge and compression.

24. Prominent Bearings
Roller and Rocker bearing (exp.) Roller and Rocker bearing (fd.)
Elastomeric Bearing PTFE bearing

25. Arch bridges
Most of the arch bridges are of old vintage. For
effectiveness and meaningful inspection of arch bridges, it
is essential that the inspecting official is conversant with
the nomenclature of various components of an arch
bridge.
Components of arch bridge

26. Major issues with Arch Bridges
Cracks in abutments and piers
Cracks associated with spandrel wall
Cracks on the face of the arch bridge
Cracking and crushing of masonry
 Leaching out of lime/cement mortar in the
barrel
Transverse cracks in the arch intrados
 Loosening of key stone and voussoirs of arch

27. Crack in pier/abutment extending
to arch barrel
Longitudinal cracks under
spandrel wall
Bulging and/or tilting of the spandrel
walls
Collapse of face wall

28. Cracks in spandrel wall due to
weakness in arch ring
Cracks in spandrel wall due to
sinking of pier
Transverse and diagonal cracks
at the intrados of arch barrel

29. Steel Bridges
Major issues with steel bridges:
 Loss of camber
Heavy overstressing of girder members, overstressing of joint rivets at
a splice in a plate girder or at the gusset in case of open web girder,
play between rivet holes and rivet shanks.
 Distortion
Insufficient restraint by bracings, tension members made up of flats,
diagonal web members generally subjected to reversal of loading,
temperature variation.
 Loose rivets and HSFG bolts
Critical areas for loose rivets: top flange of plate girders, connection
between rail bearer and cross girders in open web girders, gussets at
panel points of open web girders.

30. Major issues with steel bridges:
Corrosion
Corrosion prominent was where the top flange is coming in contact with
sleeper, water pockets formed on account of constructional features, places
where dust accumulates.
Fatigue cracks
Fatigue is the tendency of the metal to fail at a lower stress when subjected
to cyclic loading than when subjected to static loading.
Early steel girders
During those early times, the steel manufacturing technology was not fully
developed and steel manufactured in those times contained excessive
phosphorous. Higher phosphorous content makes the steel brittle and such
girders can collapse suddenly because of brittle fracture.

31. Loose rivet Corrosion of top flange
due at seat sleeper
Corrosion at
riveted connection
Crack and Corrosion at
sleeper seat
Development of crack at
riveted connection

32. Concrete Girder Bridges
Major issues with concrete bridges:
 Cracking
Diagonal cracks in the web near the support indicate excessive shear stress
and are of serious nature. Cracks which occur near the bearings may be on
account of seizure of bearings or improper seating of bearings. Longitudinal
cracks are mainly because of honeycombing in concrete and inadequate cover
which lead to ingress of moisture and early corrosion of reinforcement.
 Delamination
These can be caused by corrosion of reinforcement, inadequate cover over
reinforcing steel and fire
 Scaling
It is the gradual and continuing loss of mortar and aggregate over an area.
Scaling is usually observed where repeated freeze and thaw action on
concrete

33. Concrete Girder Bridges
Major issues with concrete bridges:
 Spalling
Spalling generally occurs with the transfer of excessive dynamic forces
(in the vicinity of bearings) or with uninhibited corrosion of
reinforcement
Wearing of concrete
Non-placement of wearing coat will lead to wear of concrete surface
and formation of depressions which will hold water and start seepage
Reinforcement corrosion
The carbonation of concrete is one of the main reasons for
corrosion of reinforcement. Of course oxygen and moisture are the
other components required for corrosion of embedded steel.

34. Cracks in concrete girders Cracks due to corrosion of steel
reinforcement
Detailing of concrete deck
slab

35. Locations to be looked for defects

36. Locations to be looked for defects

37. UNDER
WATER
INSPECTION
OF BRIDGES

38. Bridge selection criteria
Frequency of the inspection depends on:
 Age
 Type of construction material
 Configuration of the substructure
 Adjacent water features such as dams, dikes or marines
 Susceptibility of stream bed materials to scour
 Maintenance history
 Saltwater environment
 Waterway pollution
 Damage due to water-borne traffic, debris etc.

39. Methods of underwater inspection
Wading inspection
 A wading inspection can often be
performed by regular bridge
inspection teams.
 A probing rod, sounding rod or line,
waders, and possibly a boat can be
used for evaluation of a substructure
unit.
 During wading inspection, one
should preferably wear hip boots and
chest waders.
 In deeper water, wearing of a
personal floating device (PFD) may
be desirable during wading activities.
Diver practising wading

40. Methods of underwater inspection
Scuba Diving
 In scuba diving, the diver is provided
with portable air supply through an
oxygen tank, which is strapped to the
diver’s back.
 The diver is connected through an
umbilical cable with the surface and has
sufficient freedom of movement
 The maximum sustained time and
working depth in scuba diving is one
hour at 18 m depth.
 Equipment's required: circuit scuba, life
preserver, weight belt, knife, face mask
and swim fins.
Oxygen tank strapped
to Scuba diver’s back

41. Methods of underwater inspection
Surface supplied air diving
 Surface supplied air diving uses a body
suit, a hard helmet covering the head
and a surface supplied air system.
 Minimum equipments required are
diver’s mask or Jack Brown mask,
wet/dry suit, weight belts, knife, swim
fins or shoes and surface umbilical.
 Surface supplied air diving is well suited
for waterway inspection with adverse
conditions, such as high stream flow
velocity.
Surface supplied air
diving

42. Diving inspection intensity levels
Level I : Visual, tactile inspection
Level I is a general visual inspection. The Level I effort can confirm as-
built structural plans and it does not include cleaning of any structure.
Level II : Detailed inspection with partial cleaning
Level II inspection is a detailed visual inspection where detailed
investigations of selected components or sub components or critical
areas of structure
Level III : Highly detailed inspection with non-
destructive testing
Level III inspection is highly detailed inspection of critical structure or
structural element or a member where extensive repair or possible
replacement is contemplated.

43. Reporting of Inspection
The report should include the following:
- Identification and description of all major damages and
deterioration in the structure, element-wise.
- Estimate of the extent of minor damage and deterioration.
- Assessment of the general physical condition.
- Cause of damage/deterioration if known. - Water depths at
each structural element.
- Recommendations for types of maintenance and repairs
required.
- Recommendations for types and frequencies of future
underwater inspections.
- Water visibility, tidal range, water current and any other
pertinent environmental conditions.

44. Non-Destructive
Testing of
Bridges

45. NDT for concrete bridges
Rebound Hammer
Principle: Rebound of
plunger when struck with
concrete indicates strength.
Uses: Determining
compressive strength and
surface hardness
Advantages: Simple, quick,
and inexpensive.
Limitations: Not so reliable,
smoothness, age of concrete,
carbonation, and moisture
content can affect results.

46. Impact Echo
 Principle: Transmission and reflection
of electromagnetic waves
 Uses: Detection of voids, cracks,
delamination, unconsolidated
concrete, and debonding determining
thickness
 Advantages : Able to detect condition
of concrete accessible from one side
only, quick, accurate, and reliable.
 Limitations: Decreases with increase
in thickness, and accuracy depends on
impact duration.

47. Ultrasonic Pulse Velocity
 Principle: Ultrasonic wave
velocity and its attenuation.
 Uses: Homogeneity of concrete,
cracks, voids and strength
determination
 Advantages : Quick, portable,
large penetration depth, simple
interpretation, and moderate cost.
 Limitations: Not very reliable,
moisture variation and presence of
reinforcement can affect results.

48. Impulse Response
 Principle: Based on stress wave
test method.
 Uses: Detecting voids under
concrete and reinforced slabs laid
on the ground, delamination,
honeycombing in concrete
elements and checking the length
and continuity of piles.
 Advantages : Simple, easy to
handle.
 Limitations: Depends on the skill
of user, and deep damages
influence the results.

49. Acoustic Emission
 Principle: Sudden
distribution of stresses
generates elastic waves.
 Uses: Cracks, Delamination
and Corrosion
 Advantages : Fast results,
detect changes in materials.
 Limitations: Costly, defects
already present are not
detected.

50. NDT for masonry bridges
Flat Jack testing
This test is used to determine the compressive strength and in
situ stress of the masonry.
Impulse Radar
Electro magnetic waves in the band 50 megahertz to 1.5
megahertz are induced into the material by means of a
transducer and read by an antenna receiver.
 Infrared Thermography
In masonry construction, the different wavelengths often
indicate the presence of moisture. The results indicate whether
the masonry is dense/sound or porous/deteriorated.

51. NDT for steel bridges
 Liquid Penetrant Inspection(LPI)
This method is used to detect surface flaws by bleed out of a coloured
or fluorescent dye from the flaw. The method can detect the
cracks/flaws which are open to the surface
 Magnetic Particle Inspection (MPI)
MPI uses magnetic fields and small magnetic particles such as iron
fillings to detect flaws in components.
 Eddy current testing
Eddy current equipment can be used for a variety of applications
such as detection of cracks (discontinuity), measurement of
metal thickness, detection of metal thinning due to corrosion
and erosion, determination of coating thickness and the
measurement of electrical conductivity and magnetic
permeability.

52. Numerical Rating System
Bridge management

53. Numerical Rating System
Method of examination and assessment by
simple figure code, for quick appreciation of the
physical condition of the bridge.
 The system provides a means of recording
progressive deterioration.
Allows assessment of relative importance of
factors to establish priorities for undertaking
repairs/rehabilitation.
In addition, the system being numeric based, is
adaptable to computerization with all the
relevant advantages following it.

54. Condition Rating System

55. Guidelines for allotting Condition
Rating Number (CRN)
In cont.….

56. Guidelines Continued……..

57. Guidelines Continued……..

58. Guidelines Continued……..

59. Guidelines Continued……..

60. Overall Rating System

61. MAINTENANCE
OF BRIDGES

62. Settlement
Moderate Packing under superstructure
Severe -Stabilize by piles around foundation -
Do micro pilling or root piling or rebuild
Scour
Moderate -Protect by flooring - Dump boulders
around piers in scoured portion.
Severe Protect by piles around the foundation
Substructure Weathering of
masonry
Deep - Grouting with cement or epoxy -
Plaster the masonry
Vertical cracks Grouting with cement or epoxy -
Jacketing
Leaning/bulging Backfill drain - Weep holes - Soil
Anchoring/rock anchoring - Jacketing -
Rebuilding
Nature of problem and remedial measures

63. RC/PSC Girders
Cracks in
anchorage zone
- Epoxy grouting - Replace the
girder
Toe wall damaged -Rebuild them
Composite
girders
Separation of the
concrete
Retrofitting – Epoxy grouting
Defects in steel
portion
- Similar action as mentioned under
heading of steel girders.
Superstructure Weathering Pointing - Grouting with cement or
epoxy - Guniting
Cracks/bulges in -
parapet/spandrel
Draining the back fill - Providing Ties
wall
Loose rivets at
floor system joint
- Replace the rivets.
In Cont.…..

64. Training Works
Damaged pitching Repair with stone and point them
Toe wall damaged -Rebuild them
Bearings
Corroded but not
seized
-Clean and Grease it
Shearing of strips,
anchor bolt
- Check the movement of girder.
Superstructure Weathering Pointing - Grouting with cement or
epoxy - Guniting
Cracks/bulges in -
parapet/spandrel
Draining the back fill - Providing Ties
wall
Loose rivets at
floor system joint
- Replace the rivets.
In Cont.…..

65. Indian Bridge Management System
A next step forward…..

66. Thank You