A Inspection of concrete bridges-final 280410.ppt

Inspection of
Concrete Bridges

Bridge Inspection
Systematic observation of
condition and behaviour
of various components/
parts of a bridge

Inspection Includes
 Going to the bridge
 Seeing the bridge with an eye of the
Doctor (Engineer) with unaided as well
as an aided eye.
 Systematic observation over a period
of time
 “Thok baja ke dekhna”

Objectives of Inspection
• To know whether the bridge is structurally
safe
• Will it continue to be safe
• Identify actual and potential sources of trouble at
earliest possible stage
• To record systematically and periodically the
state of the structure
• To decide about the repair measures to be
taken
• To provide feedback to the designer and the
construction engineers on those features
which give maintenance problems

Current Scenario on IR
 Concrete bridges increasing with time
 Advantage of ballasted deck
 Concrete – a heterogeneous material
 Durability depends on many factors
 Affected by environmental factors

A Statement - may be
controversial
 Concrete structures are inherently
durable as compared to steel as long as
they are rationally designed and
constructed
 Deterioration of concrete is but a result
of wrong concrete mix or poor
construction work quality control.

But…
 Possibility of mistakes to happen during
construction is far greater than the steel
because
 Most of the material of a concrete structure
are supplied and assembled on site.

Therefore…
 the examples and anomalies and defects
on concrete structure, resulting from
poor quality of construction or material
are numerous in number and kind.
 The possibility for mistakes of the type is
even higher in PSC girders, where
additional processes such as pre-
stressing, grouting and erection of
girders are necessary.

and…
 There are certain phenomenon in
concrete that occur in the inside and
some which occur on the outside and
thus some can be seen and some get
manifested in the form of surface defects
over the years.
 The behaviour of those defects is not
easily predictable and analysable.
 Mostly it would be in the form of cracks

So in concrete it becomes
important to
 To find for cracks, which in the initial
stage
 study them with a view to ascertain
their cause
 Track their growth and movement

How to inspect?
 Decide number of spans to be inspected each day
 Scrutinize the previous years inspection notes
 Try to have plan, drawings and other details of
the important bridges
 Go through the drawings (important bridges to
identify critical locations)
 Plan any special inspection equipment, temporary
staging etc. (like tunnel inspection)
 Don’t rush to complete – done once a year

Precautions
 Clothing
 Glasses
 Shoes
 Scaffolding and ladders
 No short cuts please
 Watch your steps and your ego too

Inspections – Open Line
 Para 1101 SE (Works) will inspect before
monsoon every year.
 Para 1103 AEN open line will inspect after
monsoon every year.
 Para 1104 (1)(a) Important bridges and
bridges that call attention by DEN/SrDEN

Inspection- Bridge Organization
 Para 1102 SE (Br) will inspect all RCC, PSC
and Composite girders within one year of
installation
 Para 1102 SE (Br) will inspect all these
girders once in five years on planned basis
 SE (Br) will measure camber of PSC girders
once a year with any reliable method
 Para 1105 AEN (Br) shall test check 10% of
the bridges inspected by the bridge
inspector

Special Inspection (Need
based)
 When signs of weaknesses discovered
during routine or detailed inspection or
by any other observation.
 When the bridge loading is to be
increased due to revised or increased
loading standard.
 Distressed bridges.
 Exceptional events like fire, earthquake,
heavy floods etc

What to take along? (Anne. 11/15 of IRBM)
1. Pocket tape (3 or 5 m long)
2. Chipping hammer
3. Plumb bob
4. Straight edge (at least 2 m
long)
5. 30 metre steel tape
6. A set of feeler gauges (0.1 to 5
mm)
7. Log line with 20 kg lead ball
8. Thermometer
9. Probing rod
10. Wire brush
11. Mirror ( 10x15 cm)
12. Magnifying glass (100 mm
dia.)
13. Chalk/water poof pencil/pen
or paint
14. Centre punch
15. Callipers (inside and
outside)
16. Torch light (5 cell)
17. Paint and paint brush for
repainting areas damaged
during inspection
18. Gauge-cum-level
19. Piano wire
20. 15 cm steel scale
21. Inspection hammer (350-
450 gm)
22. Microscope
23. Binoculars
24. Camera
25. Crack meter
27. And common sense

What to Inspect … but
before that
 Work through a checklist prepared for the
particular type of structure.
 Should be familiar with the details of the structure
and as to how it is intended to function.
 Should study previous reports before conducting
inspection, so that the condition of the defects
noticed earlier could be checked.
 Should be aware of rectification work done earlier,
the same should be inspected and its performance
should be recorded.

…and the most important
 thing is to know and realize that every
deterioration has a cause and the aim of
inspecting official is to determine that
cause

Routine Inspection by AEN
Purpose
 Whether there is any defect in structure?
 If yes, what is the degree of the defect?
 Is it progressing?
 Is it affecting the function of the structure?
 Is there any change in the environment?
 Heavy rains.
 Other factors like trespassing and other usage
 Is it going to affect the train operation?
 Is there a necessity of doing preventive work?
 Does it require detailed inspection?

What to see?
 Cracks
 Texture of Concrete
 Wear and erosion of concrete
 Leaching of chemicals
 Stains such as corrosion in steel, dampness,
growth of algae, marine microbes
 Painting coat condition
 Bearings
 Camber
 Other observations

Cracks?
 Cracks identification
 Length
 Size
 Orientation
 Location
 Breathing of not
 Accompanying stains

Measuring Magnifier - Proceq
Least count 0.02 mm
Crack meter

Cracks?
 Cracks need to be analysed and then
only conclusions may be drawn
 All cracks lead to durability problems
 Some cracks are not serious
 Require only covering
 Other cracks are serious
 Affect load carrying capacity
 Require retro-fitment as well as covering to
prevent corrosion
 Tell tales help in decision making

Types of Cracks and spalling
 Fresh concrete
 Hardened Concrete
 Structural Cracks
 Due to loads
 Compatibility cracks
 Due to Detailing
 Corrosion
 Steel
 Concrete
 Others
 Alkali-aggregate reaction
 Sulphate attack

Cracks in fresh Concrete
 Crazing
 Plastic Shrinkage
 Drying Shrinkage
 Plastic settlement
 Long term Drying Shrinkage
 Thermal expansion/contraction
 Settlement of formwork

Crazing
 Probable Area
 Against formwork or surface
 Probable Locations
 Fair faced slabs
 Cause
 Impermeable formwork, over trawling
 Rich mixes, poor curing
 Remedy
 Improve curing and finishing
 Time of Appearance
 1-7 days, sometimes later

Plastic Shrinkage
 Probable Area
 Random over reinforcement mesh, Diagonal,
Normal to wind direction
 RCC slabs
 Cause
 Rapid early drying
 Low bleeding and fast surface evaporation
 Remedy
 Improve early curing and trowel
 Thirty min. to six hours

Plastic Settlement
 Probable Area
 Over reinforcement, Arching, Change of depth
 Deep sections, Top of Columns/ troughs
 Cause
 Excess Bleeding
 Rapid early drying
 Remedy
 Reduce Bleeding
 Reverberate mildly
 Ten min. to three hours

Early Thermal Expansion
and Contraction
 Probable Area
 External/ Internal restraint
 Thick walls, Thick slabs
 Cause
 Excess heat generation, Excess temp. gradient
 Rapid cooling, Curing by cold water
 Remedy
 Reduce heat and/or insulate, cool concrete, reduce
spacing of steel
 One day to 2-3 weeks

Long term drying shrinkage
 Probable Area
 -
 Thin walls, Thin slabs
 Cause
 Absence of movement, inefficient joints
 Excess shrinkage, Inefficient curing
 Remedy
 Reduce w/c ratio, Improve curing
 Several weeks or months

Action in case of cracks in
Fresh Concrete
 For purely surface cracks, normally no
action taken if appearance is not an issue
 In case cracks are wider and deeper, the
repair method as suitable may be
decided based on the crack size.
 In case of time dependent crack like
shrinkage and settlement – the action
should be delayed if not affecting the
structure.

Cracks in Hardened Concrete
during service

Compatibility cracks
REINFORCED CONCRETE BEAM UNDER LOAD

Crack in the deck slab
Location Reason
Bottom surface
of the deck slab
in the middle
Compatibility cracks
Excessive load on
the deck

Compatible Cracks
 Cracks which occur in course of normal loading in
RCC components for reinforcement to take the
tensile stresses. Specified in Para10.2.1 (a) of
CBC.
Environment Design Crack Width (mm)
Moderate 0.25
Severe 0.20
Extreme 0.10*

RCC Slab
Location Reason
Diagonal cracks near
support and 1m to
2m from support
Excessive shear
force

Cross cracks in center
Location Reason
Center of span Excessive Load
Less reinforcement or location
of reinforcement
Shrinkage cracks (rare)
Less Cover

Longitudinal cracks at bottom
Location Reason
Longitudinal
cracks on
lower surface
of girder
Shortage of distribution
reinforcement
Less cover to main bars
Corrosion of main bar

Cross cracks at ends
Location Reason
Transverse
cracks on
upper
surface of
girder
Shortage of bent up or top
bars in upper area
Drying Shrinkage

Location Reason
Longitudinal
cracks on upper
surface of
cantilever
Excessive load on cantilever
Less reinforcement in
cantilever
Main reinforcement in
cantilever placed lower
Crack near the support of cantilever

What to inspect in concrete bridges –
Major Bridges – PSC girders
 All the items what are there in the
small spans
 In addition
 Items related to pre-stressing (post
tensioning) and Anchorage Zone
 Slab, diaphragms, Junctions of cast in
situ and precast units or RCC/PSC
 Inside of the Box girder
 Bearings and Expansion arrangements

PSC Box
Location Reason
Perpendicular to
girder on the lower
surface of the girder
Shortage of Pre-stressing
force
Excessive Load
Breakage of PSC strand

PSC Box
Location Reason
Perpendicular to
girder on the
upper surface of
the girder
Overstressing of girder
Shortage of loading
Closes during passage
of train

PSC Box
Location Reason
Diagonal Cracks
near the support
Shear stress due to
loading
Drying Shrinkage

 All the items what are there in
the small spans
 In addition
 Slab, diaphragms, Junctions of cast
in situ and precast units or RCC/PSC
 Inside of the Box girder
 Bearings and Expansion
arrangements

Anchorage Zone
•Maximum stresses
during stressing
operation
•Concrete strength
increases with age
•Losses in Pre-stress
increases with time
•So, in no case there
can be distress after
the initial period
•If there is some
cracking it has to be
from the time of
construction

Bursting Cracks in anchorage
area

 All the items what are there in
the small spans
 In addition
 Slab, diaphragms, Junctions of cast
in situ and precast units or RCC/PSC
 Inside of the Box girder including
drainage inside the Box Girder
 Bearings and Expansion
arrangements

Location Reason
At the interface of
the precast I – Girder
and the diaphragm as
well as deck slab
Differential shrinkage
between the elements
cast at different time
Mishandling during lifting
Diaphragm
and cast-in-
situ deck or
RCC/PSC

Crack at the junction of web and the slab
Location Reason
At the
junction of the
web and the
slab
Construction joint, no crack
Relative movement due to
shear between the box and
slab

Cracks around blisters
Crack at the front
of the blister – due
to prestressing
force

Poor expansion arrangements
 If the girder not free to expand, stresses
will build up.
 Can cause cracks near the expansion
arrangement
 Choking by ballast in the expansion joint
will also cause problems

Cracks due to detailing
defects

Cracks Due to Corrosion
 Corrosion of the steel
 Corrosion Phenomenon
 Carbonation of concrete
 Volume increase on corrosion
 Alkali aggregate reaction

Electrochemical corrosion
 Iron reacts as
Fe >> Fe++ + 2e- (Anode process)
 Water takes oxygen from Atmosphere
2H2O + O2 + 4e- >>> 4 OH- (Cathode
Process)
 Fe++ and OH- creates Fe(OH)2
 Fe(OH)2 is not stable, oxidizes to
form Fe(OH)3
 Takes water to form Fe(OH).3nH2O
(Rust)

Corrosion of Steel
Fe
Fe(OH)2
Fe3O4
Fe(OH)3
Fe(OH)3nH2O
1 2 3 4 5 6
Volume

Corrosion of Steel
 Probable Area
 Natural and slow, fast if CaCl is present
 Alternate drying and wetting, humidity
 Cause
 Lack of cover and dampness, Carbonation, Chlorides
 Poor quality concrete
 Remedy
 Use dense concrete (Portland Blast Furnace Slag cement),
Dehumidify, Cathode protection
 More than two years

Corrosion of Concrete-
Carbonation
Ca(OH)2 + 2CO3 > CaCO3 + 2H2O
3CaO•2SiO2•3H2O + 3CO2 > 3CaCO3•2SiO2•3H2O
 The pH-value decreases to less than 9, which normally
is insufficient to protect the reinforcement against
corrosion.

Carbonation
X= K T ½
 Where X is measured in mm
and T in years
 K is function of concrete
strength
 Above relation is for RH 50%

Carbonation

Depth of Carbonation –
Strength of Concrete

Alkali Aggregate Reaction
 Probable Area
 -
 Damp area, shows gel type or
dried resin type deposit in cracks
 Cause
 Reactive silicates and carbonates
in aggregates reacting with Alkali
in cement
 Remedy
 Use proper aggregates, Use
Portland Blast Furnace Slag
cement, Keep water away
 More than five years

Sulphate Attack
 Sulphate salts from surrounding soil react
with C3A . No deposits like those in Alkali-
Aggregate reaction
 Use low C3A cement, Portland Blast
Furnace Slag cement
 After two years or so

Sulphate Attack
 High concentrations of sulphate ions
(SO4
- -) + Ca(OH)2 + 2H2O ->
CaSO4.2H2O + 2OH- + expansion
 Low Sulphate ion concentration
Calcium Aluminate Hydrate + CaSO4.2H2O ->
3CaO.Al2O3.CaSO4.32H2O (ettringite) +expansion
 Magnesium and Ammonium Sulphate(Serious)
MgSO4 reacts with Calcium Aluminate Hydrate
MgSO4 + Ca(OH)2 ->
CaSO4 + Mg(OH)2 + volume expansion

Texture of Concrete
 Possibility of a leakage, chemical attack by
softening, leaching
 Sulphate attack - whitening of the concrete.
 Rust stains may indicate the corrosion of
reinforcement/pre-stressing steel.
 In fire damaged structure, the colour of the
concrete gives an indication of the maximum
temperature reached.
 Wear and tear of concrete surface
 Defects like honeycombing, marine growth etc.

Corrosion stains on concrete
surface

Corrosion in reinforcement
bar

Damage to the surface of
deck slab
 Girder flooring can get worn out with
constant use
 Also if the concrete quality is not good
 Once wearing coat gets eroded and then
the girder will start wearing out
 Check under the ballast once in five
years
 Tell tale sign: water leaking from the
deck slab

STRUCTURAL CONCRETE SECTION
WEARING COAT
Formation of depressions due to
absence of wearing coat
1. The condition of deck top should be
checked after removing ballast at sample
locations
2. The drainage of the deck should be clear
3. If damage is there, will affect the life of the
structure

Drainage in Box culverts
109
Drainage in the bottom slab
• In case there is some leakage from the deck
slab, the water should be able to drain out
otherwise it will affect the durability of the
bottom slab of the Box
• These drainage spouts should be checked

Bearings
 Cleanliness around bearings
 Seating of girder on bearing
 Seating of bearing on pedestal
 Movement of the girder: actually
measured vis-à-vis theoretical
calculations
 Tell-tale signs of overstressing or locked
up movement around the bearings

Pot – PTFE bearings
 What to inspect?
 Movement during peak winter (early
morning) and peak summer (afternoon)
 Compare the movement along with temperature
with design values
 Measure dimensions to ascertain excessive
stress or strain
 Evidence of any locked up or jammed
condition
 Corrosion
 Adjoining areas of bearing for trouble

Neoprene bearings
 What to inspect?
 Titling
 Bulging
 Tearing
 Excess vibrations (soft bearings)
 Adjoining areas of bearing for trouble

Crack at the junction of cast-in-
situ end portion in PSC girders

CAMBER
 Unlike steel bridges the camber loss in
the PSC bridge would not be without
attendant warnings.
 Camber loss in PSC would result in
 Excessive cracking on the bottom surface of
Box girder or I-girder
 Separation cracks between the deck slab and
the I-girder.
 Stipulation for annual measurement of
camber

Camber
 Camber – Parameter showing overall
health of the girder
 Linked to the efficiency of the pre-stressing
force
 Nominated points chosen for recording
 Smaller spans: Mid span, end of span.
 Longer Spans: Quarter spans also
 Nominated point marked by steel or
ceramic plates fixed with epoxy
 Record carefully and accurately

Deflection of catenary (piano
wire)
Dia. of Wire (18 SWG) = Ф = 1.219 mm
Length of wire (Clear span) = L = 16 m (Roughly)
Tension on either end = T = 10 Kgf
(counter wt)
Self wt of wire/unit length (w) = (π Φ 2/4) 7.850/1000
= 0.00917 Kg/m
Deflection @ Mid-Span () = wL2/(8 T)
Where T is the Tension in wire,
= 0. 00917 x 16 2 /8 x 10
= 0.029 m i.e., 29 mm
Mid - Span
10 Kg 10 Kg
18 SWG Wire
mm

Laser range meter
Levelling
instrument
Camber at Mid-Span = R1 – {R2 + R3}/2
R2
R1
R3
Laser Meter
LASER - Light Amplification by Stimulated Emission of Radiation

PD 32 Laser range meter
Dimensions 120×65×28 mm
Weight without batteries : 220 g
Measuring Range : 0.05 to 70 m without target plate, up to
200 m with PDA 50 target plate
Accuracy : ± 1.5 mm
Operating temperature range –10°C to +50° C
Measuring functions : Single and continuous
measurement of areas and volumes.
Calculation function : +, -, x, / and special geometrical
functions
Laser : 635 nm, class 2 (IEC 825-1), class II (FDA 21 CFR)
Operating Time with 2 AA-size Batteries : Up to 15,000
measurements.

Trial results
1) CATENERY WIRE METHOD --
L1 – 0 mm, L2 – 40 mm, L3 – 0 mm
Camber = 40 mm - 29 mm (Deflection of Catenary)
= 11 mm
2) INVERT LEVEL METHOD --
L2 - 2.070 m, L1 - 2.080 m, L3 - 2.080 m
Camber = 5 mm
3) LEVELING AND LASER RANGE METER --
L2 - 1.944 m, L1 - 1.950 m, L3 - 1.939 m
Camber = 8.5 mm

Inspections – Misc. items
 Excess vibrations
 Ventillation arrangement
 Ancillary arrangements such as ladders,
railings
 Hitting of girders by road/ water borne
vehicles
 Other miscellaneous observations
including trespassing
 Bridge board
 HFL/Danger level
 Flood height gauge

Inspection arrangement for
PSC girders
 Permanent arrangement such as Cradles,
ladders, walkways etc.
 Temporary arrangements such as
ladders, challis etc.
 Mobile rail mounted inspection
arrangement
 Few purchased by the railways

Inspection platform for
piers/ abutment

Mobile crane being procured
for inspections

R: DEPTH BELOW
RAIL LEVEL: 12 M
S: HORIZONTAL
RANGE: 9 M
T: MAXIMUM
WORKING HT ABOVE
RAIL LEVEL: 8 M
a: HORIZONTAL
REACH OF
PLATFORM: 7.5 M
ROTATION OF
PLATFORM ABOUT
VERTICAL AXIS 1800
TO 3600

Inspection using crane in
progress

Defects Identified
 Technical solution to the defect
 Flow of stresses to govern the repairs.
Durability aspects important.
 If RDSO standard drawing, RDSO to be
involved in the rehabilitation.

Defects Identified
 Action to be taken as per the paras 503 -
509 of IRBM on any defects
 Analogous locations to the defect on the
same girder, and in other girders on the
same bridge or other bridges on the
system to be inspected in detail
 Efforts for identification of reasons for
the defect. Repair (covering up) not to be
the immediate goal.

Distressed Bridges
 A distressed bridge is the one which
shows physical signs of deterioration,
indicating need for rehabilitation through
special repairs, strengthening or
rebuilding (including replacement of
girders)
 If defects are noticed
 Inspect thoroughly
 Impose suitable SR, including suspend traffic,
if warranted

Distressed Bridges
 Tell tales on defects
 Detailed report to divisional office
 SrDEN/DEN to declare distressed after personal
inspection
 Report to be sent to HQ/ RDSO
 Categories
 I: Needs rehabilitation on immediate basis, say within
a year’s time
 II: Under observation, to be rehabilitated on program
basis

Distressed Bridges
 All distressed bridges may not need SR
 As a general guidance:
 Group I: SR 15 KMPH
 Settlement of foundations, deep scour around piers,
cracks in main members, wide cracks in piers/
abutments etc
 Group II: SR 25 to 50 KMPH
 Cracks in return/ wing walls, spalling of concrete,
slight leaning of spandrel wall, abutment, loose rivets,
excess vibrations etc

Distressed Bridges
 Divisions shall maintain details of distressed bridge
 Railways shall have distressed bridge diagram as per
Annex 5/1
 Inspection of distressed Bridges:

References
 Indian Railways Bridge manual
 IRICEN book on “Bridge Inspection and
Maintenance”
 RDSO report BS-48 – Inspection, Maintenance
and Rehabilitation of Concrete Bridges
 RDSO report BS-63 – Causes, Evaluation and
repairs to cracks in concrete

Few Case Studies
Based on RDSO B & S Reports

3RD GODAWARI BRIDGE NEAR
RAJMUNDRY (BS-81)

The structure
 Span 94 m
 Twin Bow string RCC arch connected by
precast RC struts in lateral direction
 12 pairs of vertical Dina Hangers
comprising 49 wires of 7mm dia
 PSC box tie girder – 16 cables each
comprising of 61 wires of 7 mm dia
 12 cross tie beams in the girder connecting
the columns hanging from Dina hangers

The problem
 Cracks on the tie beam inside the box
girders connecting the columns carrying
the load from the suspenders
 Maximum width of cracks is 0.06 mm
 All other parameters found OK
 Cracks are not found to be active
under train loads
 Crack width is within the limit given
in CBC. No cause for worry

Bridge No.73 – Vasai Creek
28 span of 48.5 m

Problem
 Longitudinal Cracks on the inside of the web of
the Box Girders (9 and 5 on West and East side to
8 and 12 in 2004)
 Width of crack varying from 0.08 mm to 0.40 mm
 Longest crack 19 m long (34.11 m in 2004 by
joining of two cracks)
 Some fine cracks seen on the outside web of the
Box Girders
 Diagonal cracks on the end block passing through
the vent hole

Current Situation
 Not much progress in the cracks
 SR of 90 Kmph
 RDSO studied thrice
 IIT Mumbai did modeling in 3-D and has
recommended that only local trains be
allowed on the bridge

What to see? Summary
All Over General Condition
Condition of surface coating
Cracks
Corrosion signs, efflorescence, rust
streaks
Scaling/ spalling
Construction joints, drainage, ladders
etc
Anchorage
zone
Cracks
Rusting
Condition of cable end sealing

What to see?
Top and
Bottom deck
slab
Cracks, Delamination, scaling
Drainage, seepage, leaching
Worn out wearing coat, abrasion
damage
Damage due to accidents etc
Support
points of
bearing and
bottom of
girder
immediately
If seating of girder is uniform
Condition of anchor bolts
Spalling/ crushing/ cracking
around bearing support

What to see?
Drainage Spouts Clogging and physical condition
Adequacy of projection of spout
on the underside
Joints in
segmental
construction
Cracks, corrosion signs
Expansion Joints If joint is free to expand/
contract
Sealing Material
Hardening/ cracking in Bitumen
Splitting/ oxidation/ Creep/
flattening/ bulging in elastomer

What to see?
Top and
Bottom flange
of I – girder
Spalling/ cracking/ scaling
Rust streaks along cables/
reinforcement
Bottom slab
in BOX girder
Spalling/ cracking/ scaling
Rust streaks
Drainage
Webs Cracks, corrosion
Diaphragms Cracks at junctions with PSC
Diagonal cracks at corners
Cracks around opening

What to see?
Expansion Joints Condition of sliding plates
Corrosion, condition of weld
Debris in joint
Check for alignment, distortion
Falling debris
Bearing (General) Check if free to rotate/ move
Check for even seating
Check for load sharing between
bearings
Physical condition
cleanliness

What to see?
Metallic Bearing Rusting/ corrosion
Condition of grease
Condition of anchor bolts
Unusual tilt of rollers
Rollers jumping off guides
Elastomeric
Bearings
Flattening, bulging
Splitting/ tearing
Non uniform thickness
Displacement

What to see?
General Trespassing by vehicles, passersby
etc and resultant damage, if any
Ladders, inspection arrangements
etc are OK or not.
Ballast retaining wall
General observations under train
movement i.e. excess vibrations,
excess deflection, odd sounds or ay
other abnormal behaviour.

A Inspection of concrete bridges-final 280410.ppt

Recommended

Recommended

More Related Content

Similar to A Inspection of concrete bridges-final 280410.ppt

Similar to A Inspection of concrete bridges-final 280410.ppt (20)

More from MdAliMujawar1

More from MdAliMujawar1 (10)

Recently uploaded

Recently uploaded (20)

A Inspection of concrete bridges-final 280410.ppt