MAITENANCE AND REHABILITATION_modified.ppt

ITP of bridges

1. INSPECTION,
MAINTENANCE AND
REHABILITATION OF
BRIDGES
S.JASWANT KUMAR
JOINT DIRECTOR (V & E)

2. INSPECTION AND MAINTENANCE OF BRIDGES
MAINTENANCE
NEED TO MAINTAIN IN TRAFFIC WORTHY CONDITION
TO FACILITATE UNINTERRUPTED FLOW OF TRAFFIC
PERIODIC MAINTENANCE INSPECTION BY
RESPONSIBLE OFFICERS ARE NECESSARY TO TAKE
TIMELY REMEDIAL MEASURES
MAINTENANE OF RECORDS FOR BRIDGES
MAINTENANCE OF MANUAL FOR MAJOR BRIDGES

3. MAINTENANCE OF RECORDS
OF BRIDGES
A bridge register should be maintained
For each bridge there must be
Original bridge report
Inspection report.
Original bridge report shall be maintained on the basis of
completion drawings. In case of old bridges where
sufficient data is not available a responsible officer shall
inspect and compile the same.

4. ORIGINAL BRIDGE REPORT
Original bridge report should contain
Bridge number
Date of investigation
Name location
Description ( type of structure, foundations etc )
Skew, spans, total length and road way width
Design live load, water way, clearances
Railing, alignment, restrictions
Miscellaneous
Date of completion
Availability of as built drawings.

5. MAITENANCE MANUAL FOR
MAJOR BRIDGES
The Engineers who are associated in the
construction of the project should also prepare
detailed maintenance manual indicating the
critical points needing special attention
subsequently during its service period.

6. INSPECTION AND MAINTENANCE OF BRIDGES
INSPECTION
ROUTINE INSPECTION
PRINCIPAL INSPECTION
SPECIAL INSPECTION
Routine inspection
Will rely mainly on visual assessment. Purpose is to
determine fairly obvious deficiencies in the bridge
structure. The frequency shall be at least once a year
but preferably twice a year before and after monsoon.
Shall be carried out by competent engineers. Up to 30
m length-A.E.E
60 m length -Dy E.E
60-200 m -E.E
200m and above -S.E
500 m -C.E

7. INSPECTION
Principal Inspection
This is a more intensive and detailed inspection
involved in close examination of elements of structure to
determine the nature and degree of distress in every
component of a bridge.
The first principle inspection shall be before expiry of
defect liability period but not later than six months after
completion and opening to traffic
The frequency there after shall not be more than 3 years
by a senior level engineer with comprehensive check list.

8. INSPECTION
Special inspection
This shall be undertaken in the event of
unusual occurrences such as earth quakes,
accidents, passage of unusual roads or floods,
unusual settlement of foundations and
substantial change in traffic pattern etc.
May require a good deal of supplementary
testing and structural analysis which will
invariably require detailed involvement of design
organizations and experts in the relevant fields

9. INSPECTION PROCEDURE
The inspection should follow a
predetermined pattern to ensure that no
component is over looked.
TYPICAL PATTERN
FOUNDATIONS
ABUTMENTS
WINGS / RETURNS
PIER COLUMNS, BEARINGS
SOFFITS OF THE DECK INCLUDING BEAMS
DETAILS UNDER THE DECK
CONDITION OF ROAD SURFACE, DRAINAGE, PARAPETS
EXPANSION JOINTS
CONDITION OF APPROACHES
CONDITION OF PROTECTIVE WORKS

10. Wyra Bridge

11. Wyra Bridge

18. INSPECTION AND MAINTENANCE OF BRIDGES
MEANS OF ACCESS
BUILTINACCESS
•MANHOLE,BUILTINLADDERS,PERMANENT CATWALKS
SEMI–MOBILEACCESS
•ACCESS LADDERS, SEMI-STATIONARY INSPECTION
EQUIPMENT
MOBILEEQUIPMENT
•EQUIPMENTOPERATINGUNDERTHEBRIDGEFROMRIVER
BED/BARGES
•EQUIPMENTOPERATINGFROMBRIDGEDECK
•MOBILEINSPECTIONUNIT
AVERYVERSATILE EQUIPMENT FORSPEEDY
INSPECTIONOFLARGENUMBEROFBRIDGES.

19. Mobile Inspection Vehicle

20. Inspection from Mobile Inspection Unit

21. ASSESSMENT TECHNIQUE & EQUIPMENT
NON DESTRUCTIVE TESTS (NDT)
REBOUND AND PENETRATION TESTS
ULTRA SOUND AND PENETRATION TESTS
COVER METERS
RESISTIBILITY TESTS
HALF CELL POTENTIAL MEASUREMENT
GAMMA RADIOGRAPH
DESTRUCTIVE / PARTIALLY DESTRUCTIVE
TESTS
By taking concrete core samples drilled from
the structure using a coring machine
CARBONATION
MOISTURE CONTENT
PULL OUT STRENGTH

22. ASSESSMENT TECHNIQUE & EQUIPMENT
LABORATORY TESTS
COMPRESSIVE STRENGTH OF CONCRETE
CEMENT CONTENT AND AIR VOIDS IN CONCRETE
MODULUS OF ELASTICITY
SPLITTING TENSILE STRENGTH
TENSILE STRENGTH OF STEEL
SULPHATE CONTENT
PERMEABIITY TESTING
REPTOGRAPHIC EXAMINATION OF AGGREGATE TO CHECK
ALKALI AGGREGATE REACTION

23. “SCHMIDT” REBOUND HAMMER

24. “ULTRASONIC PULSE VELOCITY TEST…”

25. ULTRASONIC PULSE VELOCITY (UPV)
TEST…
PURPOSE:
Thistestisusedforinitialdamageassessmentandalsofor
postrepairconditionofmembersandtoassess
-thehomogeneityofconcrete
-thein-situqualityoftheconcretesuchasto findout
thecracks,voidsandhoneycombs

26. THREETYPESOFWAVESAREGENERATED BYANIMPULSE
APPLIEDTOASOLIDMASS.
SURFACE WAVES HAVINGANELLIPTICAL PARTICLE
DISPLACEMENT ORTHESLOWEST, WHILSTSHEAROR
TRANSVERSE WAVESWITHPARTICLEDISPLACEMENTS AT
RIGHTANGLESTOTHEDIRECTIONOFTRAVELAREFASTER.
PRINCIPLE:
ULTRASONIC PULSE VELOCITY (UPV)
TEST…

27. LONGITUDINALWAVESWITHPARTICLEDISPLACEMENT INTHE
DIRECTIONOFTRAVEL(KNOWNASCOMPRESSION WAVES)
ARETHEMOSTIMPORTANTSINCETHESEARETHEFASTEST
ANDPROVIDEMOREUSEFULINFORMATION.
THEWAVE VELOCITY DEPENDS UPON THEELASTIC
PROPERTIESANDMASSOFTHEMEDIUMANDHENCEIFTHE
MASSANDVELOCITYOFWAVEPROPAGATIONAREKNOWN,IT
ISPOSSIBLETOASSESSTHEELASTICPROPERTIES.
PRINCIPLE:
ULTRASONIC PULSE VELOCITY (UPV)
TEST…

28. THETESTEQUIPMENTMUSTPROVIDEAMEANSOF
GENERATINGAPULSE,TRANSMITTINGTHISTOTHE
CONCRETE, RECEIVING ANDAMPLIFYING THE
PULSEANDMEASURINGANDDISPLAYINGTHETIME
TAKEN.
EQUIPMENT :
ULTRASONIC PULSE VELOCITY (UPV) TEST…

29. ULTRASONIC PULSE VELOCITY (UPV) TEST…
BASIC CIRCUITRY REQUIREMENTS

30. THECALIBRATIONOFTHEEQUIPMENT CANBE
DONEWITHTHEHELPOFACALIBRATEDSTEEL
REFERENCE BARSUPPLIEDWITHTHEEQUIPMENT
WHICHHASASTANDARDTRANSITTIMEOFAROUND
25MICROSECONDS.
CALIBRATION:
ULTRASONIC PULSE VELOCITY (UPV) TEST…

31. ULTRASONIC METHODS :
ULTRASONIC PULSE VELOCITY (UPV) TEST…
a. On opposite faces
b. On adjacent faces
c. On same face

32. REPETITIVE VOLTAGE PULSES ARE GENERATED
ELECTRONICALLY ANDTRANSFORMED INTOWAVEBURSTS
OFMECHANICAL ENERGY BYTHE TRANSMITTING
TRANSDUCER, WHICHMUSTBECOUPLEDTOTHECONCRETE
SURFACE THROUGH ASUITABLEMEDIUM SUCH AS
PETROLEUMJELLY,LIQUIDSOAPORGREASE.
OPERATION :
ULTRASONIC PULSE VELOCITY (UPV) TEST…

33. ASIMILARRECEIVING TRANSDUCER ISALSO
COUPLED TOTHECONCRETE ATAKNOWN
DISTANCE FROM THE TRANSMITTER AND
MECHANICAL ENERGY CONVERTED BACKTO
ELECTRICALPULSESOFTHESAMEFREQUENCY.
THEELECTRONICTIMINGDEVICEMEASURES THE
INTERVALBETWEENTHEONSETANDRECEPTION
OFTHEPULSEANDTHISISDISPLAYEDEITHERON
ANOSCILLOSCOPE ORASADIGITALREADOUT.
ULTRASONIC PULSE VELOCITY (UPV) TEST…
OPERATION:

34. TRANSDUCERS WITHNATURAL FREQUENCIES
BETWEEN 20kHzAND150kHzARETHEMOST
SUITABLEFORUSEWITHCONCRETE.
ULTRASONIC PULSE VELOCITY (UPV) TEST…
OPERATION :

35. CONCRETE QUALITY GRADING CHART
ULTRASONIC PULSE VELOCITY (UPV) TEST…

36. PROFOMETER (COVER METER)

37. THEBASICPRINCIPLEISTHATTHEPRESENCE OF
STEELAFFECTSTHEFIELDOFANELECTROMAGNET .THIS
MAYTAKETHEFORMOFANIRON-COREDINDUCTOROFTHE
TYPESHOWNINFIGURE.
ANALTERNATINGCURRENTISPASSEDTHROUGH ONEOF
THECOILS,WHILSTTHECURRENTINDUCEDINTHEOTHER
ISAMPLIFIEDANDMEASURED,USUALLYBYAMOVING-COIL
METER.
COVER METER : THEORY
ELECTRO MAGNETIC METHODS…

38. AREFINEDVERSIONOFTHISTYPEOFEQUIPMENT,
INVOLVINGMORESOPHISTICATEDELECTRONICCIRCUITRY
ISAVAILABLEATPRESENTANDISCAPABLEOFINDICATING
BARDIAMETERANDALSODETECTINGBARSATAGREATER
DEPTH..
COVER METER : THEORY
ELECTRO MAGNETIC METHODS…

39. MOST COVER METERS CONSIST OFAUNIT
CONTAININGTHEPOWERSOURCE,AMPLIFIERANDDIGITAL
DISPLAYANDASEPARATESEARCHUNITCONTAININGTHE
ELECTROMAGNET WHICHISCOUPLEDTOTHEMAINUNITBY
ACABLE.
INUSE,THEREADINGINTHEDISPLAYUNITWILLBEZERO
ANDTHEHANDHELDSEARCHUNITMOVEDOVERTHE
SURFACEOFTHECONCRETEUNDERTEST.
COVER METER : PROCEDURE
ELECTRO MAGNETIC METHODS…

40. THEPRESENCE OFREINFORCEMENT WITHINTHE
WORKINGRANGEOFTHEEQUIPMENTWILLBEINDICATED
BYMAKINGABEEPSOUND.
THESEARCHUNITISTHENMOVEDANDROTATEDTO
OBTAINAMAXIMUM READINGANDTHISPOSITIONWILL
CORRESPOND TOTHELOCATIONOFABAR(MINIMUM
COVER).
COVER METER : PROCEDURE
ELECTRO MAGNETIC METHODS…

41. PRESENCEOFMORETHANONEREINFORCINGBAR.
LAPS,TRANSVERSE STEELASASECOND LAYEROR
CLOSELY-SPACEDBARS(LESSTHANTHREETIMESTHE
COVER)MAYCAUSEMISLEADINGRESULTS.
METALTIEWIRES,WHERETHESEAREPRESENTOR
SUSPECTED,READINGSSHOULDBETAKENATINTERVALS
ALONGTHELINEOFTHEREINFORCEMENT ANDAVERAGED.
COVER METER : LIMITATIONS
ELECTRO MAGNETIC METHODS…

42. THEMOSTRELIABLEAPPLICATIONOFTHISMETHOD
TOIN-SITUREINFORCEMENT LOCATION ANDCOVER
MEASUREMENT WILLBEFORLIGHTLYREINFORCED
MEMBERS.
ASTHE COMPLEXITY AND QUANTITY OF
REINFORCEMENT INCREASES,THEVALUEOFTHETEST
DECREASESCONSIDERABLY.
COVER METER : LIMITATIONS
ELECTRO MAGNETIC METHODS…

44. CARBONATION TEST
Carbondioxidepresentintheatmospherereactswith
hydratedcementproductsinthepresenceofmoisture
toformcalciumcarbonate.Thisactslikeasponge&
provideaccessforoxygen&moisturetoreach
reinforcement.
Test: pHindicatorsolutionused.
Phenolphthalein+dilutealcohol
Sprayonfreshlyexposedsurface

45. IfconcreteblusheswithPinkcolour,concrete
isalkaline/notcarbonated.
Ifcolourless–concreteissick
Testtobeconductedatvariousdepths.Depth
ofcarbonationtobefoundout
CARBONATION TEST…

46. CHLORIDE PENETRATION TEST
CHLORIDEDETERMINATION TESTWILLBECARRIED
OUTONCONCRETE TOESTIMATETHELEVELOFCHLORIDES
INTHECONCRETE.
THEPRESENCEOFHIGHERAMOUNTOFCHLORIDESIN
CONCRETE SURROUNDING THEREINFORCEMENT WILL
RESULTINCORROSIONOFREBARS.
THEQUANTITYOFCHLORIDES INCONCRETE IS
DETERMINED GENERALLY BYCHEMICAL ANALYSISAND
EXPRESSED INTERMSOFPERCENTAGE OFCHLORIDESBY
WEIGHTOFCONCRETE.
* * * * *

47. INPSECTION REPORT AND FOLLOW UP ACTION
INSPECTION REPORT SHALL BE IN PRESCRIBED FORMAT
WITH SKETCHES OR PHOTOGRAPHS
RECOMMENDATIONS FOR STRENGTHENING AND
REPAIRS OF THE EFFECTED COMPONENTS
IF BRIDGE IS IN DISTRESS
LOAD ON BRIDGES SHALL BE RESTRICTED
BRIDGE CLOSED WHOSE RATED CAPACITY IS LOWER THAN
LEVEL OF TRAFFIC EXPECTED TO PLY
REPLACEMENT OR STRENGTHENING OF BRIDGE

48. MAINTENANCE OPERATION
Maintenance operations can be of ordinary
maintenance and specialized maintenance . The
important aspects to be kept in view are
Bridges in severe exposure condition
mainly in coastal regions are vulnerable to
corrosion. Hence any sign of distress,
cracks are to be observed twice a year.
In case of bridges in major alluvial rivers
deep scour may occur near piers even with
smaller discharges. Hence soundings
before, during and after floods are to be
taken at all foundations.

49. MAINTENANCE
MAINTENANCE OF SUBMERSIBLE BRIDGES
TRAFFIC ON THE BRIDGE TO BE SUSPENDED
IMMEDIATELY IF THE WATER REACHES SPECIFIED LEVEL
VENTS PROVIDEDIN SUPERSTRUCTUE TO BE CHECKED
SUPERSTRUCTURE TO BE CLEARED FREE OF DEBRIS
AFTER RECEDING OF FLOOD
GUIDE POSTS, SUPERSTRUCTURE TO BE EXAMINED FOR
DISTRESS
MISCELLANEOUS ITEMS
WEARING COAT
DRAINAGE SPOUT
FOOTPATHS
EXPANSION JOINTS
HAND RAILS

50. MAINTENANCE
Protective works
Most careful patrolling and watch is necessary
during each flood season especially the first
flood season to detect any weakness in
construction.
Engineer-in-charge should acquaint himself
with past history of the protective works and the
behavior of the river
It is advisable to have a reserve quantity of
stone which can be used in case of any
emergency for aprons, slope pitching etc.

51. REPAIR AND REHABILITATION
REHABILITATION OF BRIIDGES
The bridges are vital links in the highway
network and it for any reason the bridge goes
out of commission, the resultant disruption of
traffic effects the network. Hence it is well
recognized that bridges not only require
systematic maintenance but also strengthening
or rehabilitation during their service life.

52. APPROACH FOR
REHABILITATION
The best strategy can be only be determined in the light
of
Thorough investigation
Diagnosis of the causes of deterioration, faults and
weakness and
Assessment of the current condition of the bridge
Wherever possible root cause should be eliminated
before repairs are undertaken. Repair and strengthening
operations should be mechanically and chemically
compatible with the properties of the original or
surrounding material and basic structural concept.

53. REHABILITATION
Major causes of distress
•Single main cause of premature
deterioration of concrete bridges is
corrosion of steel . High humidity, porosity
of concrete, inadequacy of cover, cracks in
cover concrete, use of rusted steel
reinforcement without proper cleaning and
lack of proper grouting in cable ducts are
some of the factors which aggravate the
problem

54. CAUSES OF DISTRESS (contd)
Aggregate alkali reaction and alkali silica reaction
resulting in either in pop-outs or cracks in concrete
caused by expansion of reactive aggregate.
Leaching action and sulphate attack
Poor detailing, lack of strict quality control during
execution
Foundation movements due to scour, seismic activity
Manufacturing and damage to expansion joints
Excessive displacement of bearings
Lack of preventive routine maintenance

55. SIGNS OF DISTRESS
Cracking due to corrosion or map cracking.
Scaling which is local flaking or peeling off of
surface portion of concrete
Delaminations parallel to the concrete surface
at or near the level of reinforced steel indicating
corrosion and ultimate spalling of concrete
Leaching in the form of accumulation of white
salt or lime deposits on concrete surface

56. SIGNS OF DISTRESS (contd)
Deformation in the form of localized swelling or
expansion indicating compressive failure of
concrete or initial stages of spilling
Excessive deflection of super structure or
movement of bearings indicated by closing or
widening of expansion joints, tilting of
piers/abutments and well foundations.
Displacement of railings longitudinally and
transversely .

57. STEPS IN REHABILITATION
EVALUATIONOFTHESTRUCTURE FROMDOCUMENTED
DATABASEANDINSPECTIONS.
LOCATINGDAMAGES/DEFECTS/DISTRESS
ANALYSISOFCAUSESOFDAMAGES /DEFECTSAND
DISTRESS
EVALUATIONOFRESULTSOFSTRUCTURALASSESSMENT
DESIGNOFREPAIRSFORREHABILITATIONWORKS
PROPOSALSANDESTIMATIONOFCOSTS,I.E.,OPTIONSOF
WHETHERTOTALREPLACEMENT OFTHESTRUCTURE OR
ACOMPARISON OFPARTIALREPLACEMENT ANDREPAIR
BASEDONTHESEVERITYOFDAMAGE INLOCALISED
AREASOFTHESTRUCTURE.

58. NORMALLY OBSERVED DISTRESS
ARCHBRIDGES
CHANGEINPROFILEOFTHEARCH
LOOSENINGOFMORTARBECAUSEOFAGEINGEFFECT
ARCHRINGDEFORMATION
MOVEMENT OFTHEABUTMENTORPIERS
LONGITUDINALCRACKS
LATERAL ANDDIAGONAL CRACKS INDICATEA
DANGEROUS STATE
CRACKSBETWEEN THEARCHRING,SPANDRELOR
PARAPETWALL
VERTICALCRACKINRETURN WALL,BULGINGOF
CRACK

59. NORMALLY OBSERVED DISTRESS
II)RCCBRIDGES
CRACKING
•CRACKSCOULDBEOFDIFFERENTTYPESANDCAN
BEDUETOSEVERALREASONSLIKE
•PLASTICSHRINKAGEANDSETTLEMENT
•DRYINGSHRINKAGE
SETTLEMENT
STRUCTURALDEFICIENCIES
REACTIVEAGGREGATES
CORROSIONOFREINFORCEMENT
EARLYTHERMALMOVEMENT
SULPHATEATTACK
FROSTDAMAGE
PHYSICALSELFWEATHERING

60. NORMALLY OBSERVED DISTRESS
II)RCCBRIDGES
SCALING
DELAMINATION
SPALLINGOFCONCRETE,ASEROUSDEFECTBECAUSEOF
CORROSIONOFTHEREINFORCEMENT, OVERSTRESSESETC.
LEACHING
STRAINS
HOLLOWORDEADSOUND
DEFORMATION
EXCESSIVEDEFLECTIONS
HOLESINDECKSLAB

61. NORMALLY OBSERVED DISTRESS
III)PSCBRIDGES
HORIZONTAL CRACKS NEARENDSOFPSCMEMBER
INDICATE,DECIFIENCYOFREINFORCEMENT STEELTOLATER
BURSTINGFORCES
VERTICALCRACKSATSUPPORTISARESULTOFRESTRICTED
MOVEMENT OFBEARINGS
IV)STEELBRIDGES
CORROSION
EXCESSIVEVIBRATIONS
EXCESSIVEDEFLECTIONANDDEFORMATION LIKEBUCKLING,
KINKING,WARPINGETC.
FRACTURES
DISTRESSINCONNECTIONS
FATIGUECRACKING

62. REPAIR
CRITERIA FOR SELECTION OF MATERIALS &
TECHNIQUES
CAUSE OF DISTRESSES, EFFICACY OF MATERIALS
AND IN PRESERVING / INCREASING THE LOAD
CARRYING CAPACITY OF THE STRUCTURE
AVAILABILITY OF MATERIAL / EQUIPMENT
IMPORTANCE OF THE BRIDGE
TIME AVAILABLE
LIFE EXPECTANCY
FEASIBILITY OF TRAFFIC DIVERSION

63. REPAIR
REPAIRS OF FOUNDATION
EROSION PROBLEMS
•STONE RIP RAP IS PLACED ON A MATTRESS AT (OR)
BENEATH BED LEVEL
PROBLEMSAGAINSTSCOUR
•SPURDYKES
•DEFLECTIONS TODIVERTWATERAWAYFROMPIERS
GARLANDING TECHNIQUE WITHSTONESAROUND PIER
FOUNDATIONS
•RCCCURTAINWALLS
•INCREASINGBEARINGCAPACITYBYINJECTINGCEMENT/
CHEMICALGROUT

64. REPAIR
REPAIRS TO MASONRY STRUCTURES
LOSS OF BOND FOR THE CORNER STONE
•LOWPRESSURECEMENTGROUTORAPOXYMORTAROR
PUSHINGSTONEBACKTOORIGINALPOSITIONBYFLAT
JACKS
LONGITUDINAL CRACKS ALONG DIRECTION OF
TRAFFIC
•RAKEMORTARJOINTSANDREFILLWITHCEMENTMORTAR
TRANSVERSE CRACKS
•INJECTIONOFCEMENT
STRENGTHENING OFARCHRING
•BYADDINGMATERIALTOTHEINTRUDESORTOTHE
EXTRUDES

65. REPAIR
REPAIRS TO STEEL STRUCTURES
•DECKREPLACEMENT OFOLDERSTEELBRIDGES
•STRENGTHENING OFSTRUCTURALMEMBERS
•CRACKREPAIR
CANBEMADEBYTECHNIQUES SUCHASDRILLING
HOLESATTHECRACKTIP,CUTTING OUTTHE
CRACKEDMATERIALANDBOLTINGPLATESINPLACE,
CUTTINGOUTTHECRACKANDREWELDING WITHA
HIGHERCLASSWELD
•UNDERWATERWELDING ARC WELDING AN
ACCEPTEDPROCEDURE
•STEELARCHSUPERIMPOSITION TOSTRENGTHEN
OLDTRUSSBRIDGE

66. REPAIR
REPAIRS TO CONCRETE BRIDGES
CLASSIFIED AS
REPAIR OF THE CONCRETE SURFACE
REPAIR OF CRACKS
REPAIR OF CORRODED STEEL REINFORCEMENT
REPAIR OF POROUS CONCRETE AND HOLES
REPAIR OF THE CONCRETE SURFACE
MECHANICAL METHODS
•MILLING, CHIPPING, SAND BLASTING, WATER OR STEAMS
HYDRAULIC METHODS
•WATER JETTING WITH 10 TO 40 MPA PRESSURE

67. REPAIR
BONDING AGENTS
CEMENT PASTE
CEMENT SLURRY
POLYMER MODIFIED CEMENT SYSTEM
RESINS
CONCRETE SURFACE PROTECTION MEASURES
IMPREGNATION -SILICON ORGANIC SOLUTIONS
RESINS
OILS -BOILED LINSEED OIL
SEALERS -EPOXY, POLY URETHANE RESINS (PU)
COATINGS

68. REPAIR
REPLACEMENT OF SUBSTANDARD DEPTH OF CONCRETE
SLABS
REPLACEMENT OF CONCRETE SECTION IS NEEDED WHERE A
SMALLER SURFACE REPAIR IS NOT DESIRABLE
METHODS
SHORTCRETE
SUITABLE FOR REPAIR OF SURFACE DAMAGES,
CONCRETE REPLACEMENT AND FOR STRENGTHENING
OF STRUCTURAL ELEMENTS
•A DRY MIX PROCESS
•A WET MIX PROCESS
POLYMER MODIFIED CEMENT SYSTEM
RESINS

69. REPAIR
REPAIR TO CRACKS
ACTIVE CRACKS
•CAULKING, JACKETING, STITCHING, STRESSING INJECTION
CRAZING
•GRINDING, COATINGS, SAND BLASTING, PNEUMATICALLY
APPLIED MORTAR
HOLES AND HONEY COMB
•TOTAL REPLACEMENT, COMBINING PNEUMATICALLY
APPLIED MORTAR
EXCESSIVE PERMEABILITY
•COATINGS, JACKETING, PREPACKED CONCRETE, TOTAL
REPLACEMENT, GROUTING
MATERIALS
EXPOXY RESINS
POLYURETHENE RESINS
ACRYL RESINS

70. REPAIR
PROTECTION OF REINFORCING STEEL
FOR RUST REMOVAL
•SAND BLASTING,
•NEEDLE HAMMER
•WIRE BRUSHING
PROTECTION COAT WITH CEMENT MORTAR
CEMENT MORTAR WITH POLYMERS

71. REPAIR
STRENGTHENING OF CONCRETE STRUCTURE
REPLACING POOR QUALITY / DEFECTIVE MATERIAL
PROVIDING ADDITIONAL LOAD BEARING MATERIAL
•HIGH QUALITY CONCRETE, STEEL BARS, THIN PLATES
AND STRAPS, POST TENSIONING TENDONS
JOINT BETWEEN OLD AND NEW CONCRETE MUST BE
CAPABLE OF TRANSFORMING SHEAR STRESS WITHOUT
RELATIVE MOVEMENT
REINFORCEMENT STRENGTHENING
REPLACEMENT OF REINFORCEMENT SEVERELY DAMAGED
ADDITIONAL REINFORCEMENT PLACED
EPOXY BONDED STEEL PLATES

72. REPAIR
REPAIR TO
EXPANSION JOINTS
NOT EXPECTED TO LAST THROUGHOUT LIFE OF THE
BRIDGE
SEALANT FILLER SHALL BE REPLACED PERIODICALLY
REPLACEMENT OF CRACKED CONCRETE IN THE SONE OF
ANCHORING
BEARINGS
DEFECTS
•CORROSION
•DEFECTIVE SEAL IN NEOPRENE / POT BEARINGS
•PROKEN GUIDES
•CRACKED OR BROKEN ROLLER PLATES
•ACCUMULATION OF DUST / DEBRIS AT THE BEARING
JOINT

73. REPAIR
REPAIR TO
FOOTPATHS
REPLACEMENT OF DAMAGED / MSSIONG PRECAST
FOOTPATH SLABS
RAILINGS
REPAIR MEASURES ARE SAME AS ARE TO BE DONE FOR
MATERIAL WITH WHICH THEY ARE MADE

74. REPAIR
HYDRAULIC ASPECTS
ACTUAL DISCHARGE IN EXCESS OF THAT ASSUMED IN THE
DESIGN
INCREASE IN VELOCITY OF THE RIVER / STREAM FROM
THAT FOR WHICH IT WAS DESIGNED
INCREASE IN SCOUR DEPTH
DAMAGE TO THE PIERS OF THE BRIDGE DUE TO IMPACT OF
FLOATING DEBRIS
OBLIQUE FLOW OF THE STREAMS
THE CAUSES OF THESE OCCURANCES SHALL BE
ANALYSED AND SUITABLE REMEDIAL MEASURES TAKEN

75. MONITORING
AFTERTHEBRIDGESTRUCTURE ISREHABILITATED,
ITISESSENTIALTHATTHESAMEISKEPTUNDER
OBSERVATION ANDITSCONDITION MONITORED
REGULARLY.THEMONITORING METHODS MAY
INVOLVECARRYINGOUTCERTAINLABORATORY AND
FIELDTESTSASWELLASCONDITIONSURVEYSAND
MEASUREMENTS TODETECTEVENSMALLSTRAINS,
MOVEMENT ETC.MOREFREQUENT INSPECTION
DURINGREPAIRSANDATANINTERVALOF6MONTHS
THEREAFTERMAYBEREQUIRED.

76. Rehabilitation
of
Wyra Bridge

77. Sign
Board :“ BRIDGE UNDER MAJOR REPAIR, TAKE DIVERSION”

78. CHRONOLOGY
Commencement of Construction : 1992
of Bridge
Completion of Construction : December 1994
and Commissioning
Noticing of Cracks in girders : December 1995
for the first time
Closure of bridge for traffic : December 1997
**********

79. Salient features of
the Bridge

80. SALIENT FEATURES OF THE BRIDGE
Location : Across “Wyra Surplus” at 88 km, Suryapet
Aswaraopet Rd(near Khammam, A.P)
Bridge Structure: R.C. Deck with 3 girders resting on r.c.
piers supported on open foundation
Span : 10 spans each of 16.5 mtrs
[Simply supported spans]
Materials for : Fe-415 Rebars
Construction M20 Concrete for deck
M15 Concrete for piers

81. DESIGN DETAILS
Number of lanes: Two
Carriage Way : 7.5 m
Loading /Deck : One Lane Class70-R (Wheeled/Tracked)
or
Two Lanes of Class ‘A’ Vehicle
Reference : Std. plans for highway bridges-T Beam
bridges (Vol.III)MOST -1983. Dg. 29
IRC Specifications

85. CROSS SECTION OF DECK

86. LONGITUDINAL SECTION OF DECK

89. VIEW OF DECK BOTTOM

90. What happened
to the bridge?

91. DECEMBER 1997

95. Physical Observations/
Summary
SPANS -S6,S8 AND S9(SEVERE DISTRESS)
1. WIDE CRACKS -VERTICAL /HORIZONTAL
2.SPALLING OF CONCRETE
3.EXPOSURE OF REBARS
4.SAGGING OF SPANS (MAX. ABOUT 75mm)
5. CRUSHING OF CONCRETE AT SUPPORTS
(BY ABOUT 50 mm)
6.SEVERE PERCEIVABLE VIBRATIONS
7. POOR QUALITY CONCRETE

96. Physical Observations/
Summary (Contd..)
SPANS -S1, S2, S3, S4, S5, S7 AND S10
(MODERATE DISTRESS)
1. MODERATE CRACKS -VERTICAL /
HORIZONTAL
2. POOR QUALITY CONCRETE

97. Temporary measures
undertaken
by the department

98. TEMPORARY SUPPORTS

102. Examination of the
bridge

103. BRIDGE INSPECTION VEHICLE

129. Why Concrete in lower region of Girders is Poor?
Is it because -
1. Defective cement is used.
2. Mix proportion is lean.
3. Quality of aggregates is poor .
4. Water-Cement ratio is high.
5. Curing is not adequate.
6. Form work is not slurry tight.
*******

130. Decision
Demolition Or
Restoration?

131. CLIENT :R & B Department, Govt. of A.P
CONSULTANT FOR :Torsteel Research Foundation
RESTORATION in India, Bangalore
INVESTIGATIION : March/April 1998
RESTORATION RepCon Consultancy
AGENCY :& Services, Hyderabad
PERIOD OF :October 1998 to
RESTORATION February 1999
RECOMMISSIONING : March 1999
OF BRIDGE

132. Preparatory measures
for
Restoration

133. RECOMMENDED ADDITIONAL SUPPORTS
(SECTION)

135. Restoration Scheme
Design

136. Popular Restoration Schemes
1. Substitution techniques
2. Encasement techniques
3. Wrapping-Round techniques
4. Shortcreting techniques
5. Pressure grouting
6. Prestressing techniques
7. Material Strengthening techniques

137. RESTORATION SCHEME DECIDED FOR
THE BRIDGE PROJECT
STAGE I : Replacement of poor concrete in
girders & diaphragms, by good
concrete.
STAGE II : Replacement of poor concrete in
bearing regions, by good
concrete.

138. RESTORATION SCHEME DECIDED FOR
THE BRIDGE PROJECT (Contd..)
STAGE III : Replacement of neoprene pads.
STAGE IV : Pressure grouting of girders &
diaphragms.
*****

139. RESTORATION MATERIALS
Several restoration materials have been developed
in the recent past,which ensure safe and durable
restorations. A few of them are -
Modified Mortars.
Epoxy Mortars.
Cementitious/Epoxy Grouts.
Membrane/Protective Coatings.
Glass Fiber / Carbon Fiber wrappings
Free Flow Micro Concrete.
(Super Fluid Micro Concrete)
Free Flow Micro Concrete is an ideal material for
encasement / Substitution systems

140. ESSENTIAL REQUIREMENTS OF REPAIR
MATERIALS IN CONCRETE STRUCTURES
•Effective adhesion with parent concrete.
•Development of positive grip with reinforcements .
•Fast gain in strength.
•High degree of impermeability.
•Durability under adverse atmospheric conditions.
Free Flow Micro Concrete satisfies by and large,
these essential requirements and is amenable for
encasement/Substitution techniques.

141. WHAT IS FREE FLOW MICRO CONCRETE ?
It is nothing but an appropriate synthesis of ‘free flow
grout’ & ‘dust free clean coarse agg.’
General Mix :
1.0 Free flow grout -0.5-coarse agg. by wt.
Expected slump -Collapse slump
Segregation -Nil
It is termed micro-concrete since 6mm agg. is used.
It is a potential restoration material.

142. CHARACTERISTICS OF FREE
FLOW GROUT
Form : Powder Type, Cementitious
Grain Size : 0 -3 mm in general
Unrestrained Expansion : About 2%
Flowability at max. : About 2000 mm in
consistency of 200 mm gap width of about 25 mm
Comp. Str. at 24 hrs : 250 Kg/Sq.cm min.
with max.consistency

143. FREE FLOW GROUTS
Grouts often used are -
•Sika grout -from M/s. Sika Qualcrete
•Conbextra GP -from M/s. Fosroc Chemicals
•Master grout CNS-from M/s. Choksey Chemicals
•Emcekrete -from M/s. Mc. Bauchemie
•Shrinkkomp -from M/s. Associated Cement
Company etc...

144. How does free flow micro
concrete look like?

149. Execution of Restoration
Scheme
(replacement of poor concrete
by free flow micro concrete)

150. RESTORATION DESIGN

151. RESTORATION DESIGN

152. RESTORATION DESIGN
FREE FLOW MICRO CONCRETE
TO BE POURED WITHOUT
COLD JOINT IN TWO STAGES
FREE FLOW MICRO CONCRETE

159. RESTORATION DESIGN

171. Execution of Restoration
Scheme
(restoration of bearing regions
& replacement of bearings)

172. LIFTING OF BRIDGE DECK FOR CONCRETE
REPLACEMENT AT BEARINGS

173. LIFTING OF BRIDGE DECK -INSERTION OF JACKS

174. LIFTING OF BRIDGE DECK -LIFTED DECK IN
POSITION

175. LIFTING OF BRIDGE DECK -ELEVATION AFTER
LIFTING

183. Execution of Restoration
Scheme
(pressure grouting of girders
& diaphragms)

187. Bridge Structure after
Restoration

193. Post -Restoration
Tests

195. LOAD / CONFIDENCE
TEST

196. LOAD / CONFIDENCE TEST DETAILS
Date of Test: 25
th
-28
th
January1999
Total u d l on Deck: 82 tonnes
considered for testing
Impact Factor : 20% of the above
Test load applied: 1.25 [1.2 x 82]
123 tonnes
Stone masonry wall around & 0.95 m depth of
water amounted to about 123 tonnes
RESULTS
Max. defln. under test load: 2.05 mm 1/8000 (span)
Crack width : Zero at 95% test load
< 0.1 mm at test load
Closure on load removal

197. CONFIDENCE TEST

199. CONFIDENCE TEST

200. Economics !

201. RESTORATION COSTING
Quantum of free flow micro
concrete utilised : 95 Cum
Quantum of addl. reinforcement : 10 tons
bars
Total Cost of Restoration : Rs. 35 lakhs
Cost of Super Structure : Rs. 85 lakhs
(As on 1997)

203. Recommissioning of
the Bridge

205. Recommissioning of Bridge

206. Present Status
Performing very well
Free from any distress

207. Rehabilitation
Masonry Bridge
Nalgonda-Mahabubnagar Road

212. REFERENCES
CONCRETEBRIDGEHANDBOOKBYV.K.RAINA
IRCSP35–1990GUIDELINESFORINSPECTION
ANDMAINTENANCE OFBRIDGES.
IRCSP40–1993GUIDELINESFORTECHNIQUES
FORSTRENGTHENING ANDREHABILITATIONOF
BRIDGES
POCKET BOOK FORBRIDGE ENGINEERS
(MORTHPUBLICATIONS2000)
SPECIFICATIONFORROADANDBRIDGEWORKS
–1995(3
RD
REV.)-MORTH
IS456–2000CODEOFPRACTICEFORPLAIN
ANDREINFORCEDCONCRETE.

213. THANK YOU
THANK YOU