UNDERWATER INSPECTION OF BRIDGES ILLUSTRATED WITH CASE STUDY

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UNDERWATER INSPECTION OF BRIDGES ILLUSTRATED WITH
CASE STUDY BY Shri.K.Simon, Dy.CE/C/SCR
Shri Mohd. Bakhsh, Dy.CE/W/WR Shri .A.Raj Kumar,
DEN/SR
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WHY UNDER-WATER INSPECTION?

• TO ENSURE SAFE CONDITION
• OF SUB-STRUCTURE DURING
• THE COURSE OF ITS LIFE.

• TO DETECT ANY DISTRESSED
• CONDITION OF SUB-STRUCTURE
• OUT LIVED OR PRE-MATURE

• TO PREVENT ANY POSSIBLE
• MISHAP DUE TO STRUCTURE
• FAILURE BY TIMELY ACTION

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WHERE UNDER-WATER INSPECTION IS ESSENTIAL?

• IT IS REQUIRED TO CHECK THE SUBSTRUCTURE OF ALL
• BRIDGES OVER PERENNIAL RIVERS BACKWATERS.

• ON BRIDGES WHERE SUBSTRUCTURE CANNOT BE
• INSPECTED DUE TO SUBMERGING UNDER WATER

WHAT SHALL BE INSPECTED IN UW INSPECTION?

• CAVITY IN MASONRY /CONCRETE
• JOINTS IN MASONRY /CONCRETE
• LOOSE/ MISSING STONE/BRICKS IN MASONRY
• WEATHERING OF MASONRY
• EXPOSURE OF REINFORCEMENT

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WHAT SHALL BE INSPECTED IN UW INSPECTION?
(CONTD)

• RUST STAINING, CRACKING, SPALLING, ABRASION,
  DISINTEGRATION IN CONCRETE STRUCTURES
• BULGING IN SUB STRUCTURE
• STEEL WORKS
• --CI PIPES
• -- STEEL CAISSONS
• -- SCREW PILES
• CORRECT LOCATION AND IDENTIFICATION OF DEFECTS IS
  IMPORTANT

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Anerobic Bacterial Growth
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Scaling of concrete
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Spalling of concrete
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Disintegration of concrete
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Deep Cavitation
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WHO WILL DO UNDER-WATER INSPECTION?

• ONLY WELL TRAINED PERSONNEL

• PRACTICAL PROBLEM IS THAT IN MAJORITY OF THE
• CASES ONLY EXPERT DIVERS ARE USED BUT THEY
• WILL NOT HAVE ANY EXPERTISE IN CIVIL/ BRIDGE
  ENGG.

WHAT IS LAID DOWN IN OUR CODES ON THIS TOPIC?

• CODES INCLUDING IRBM98 IS SILENT ABOUT THIS
  ASPECT

• AFTER TRAGIC KADALUNDI ACCIDENT, BASED ON CCRS
• RECOMMENDATIONS, RDSO HAS BROUGHT OUT BS-40
• GUIDE LINES FOR UNDERWATER INSPECTION OF BRIDGES
• DURING THE YEAR 2001.

CES CIRCULAR No.3/2002 OF Srly PRESCRIBED 2
YEARS FERQUENCY
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WHEN TO CONDUCT UNDERWATER INSPECTION?

• BS-40 SUGGESTS DURING THE PERIOD OF LOW WATER
• OR LOW POLLUTION LEVELS OR GOOD VISIBILITY
  (UNDER)

• 20 OF UNDERWATER UNITS FOR EACH BRIDGE SELECTED
  RANDOMLY SHOULD BE INSPECTED. THE RANDOM
  INSPECTION SHOULD BE MADE IN SUCH A WAY THAT
  ENTIRE STRUCTURE IS COVERED IN 5 YEARS

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METHODS OF PERFORMING UNDER-WATER INSPECTION
1.WADING INSPECTION BASIC, REGULAR METHID OF
INSPECTION PROBING/SOUNDING ROD
2.SCUBA -SELF CONTAINED UNDERWATER BREATHING
APPRATUS
3. SURFACE SUPPLIED AIR DIVING OR MIXED GAS DIVING
4.DEEP SEA DIVING NOT USED FOR BRIDGE INSPECTION
SCUBA DIVING

• SCUBA DIVER IS PROVIDED WITH PORTABLE AIR SUPPLY
• IS CONNECTED TO SURFACE THROUGH AN UMBILICAL
• CABLE

• MIN.EQUIPMENT ARE SCUBA, LIFE PRESERVER,WEIGHT
• BELT, KNIFE,FACE MASK AND SWIM FINS

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. CONTD SCUBA DIVING)

• IS SUITED WHEN MANY DIVES OF SHORT DURATION
• ARE NEEDED MOBILITY IS THE PRIME CONSIDERATION

• MERITS ARE RAPID DEPLOYMENT, PORTABILITY, MIN.
• SUPPORT AND EXCELLENT MOBILITY

• DEMERITS ARE DEPTH LIMITATION, MIN.AIR SUPPLY
• LACK OF VOICE COMMUNICATION FROM
  SURFACE

• MAX. SUSTAINED TIME AND DEPTH IS ONE HOUR _at_18 M

• DIVING TEAM SHOULD HAVE 3 MEN BOAT IS REQUIRED

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SURFACE SUPPLIED AIR DIVING

• AIR IS SUPPLIED TO THE DIVER THROUGH UMBILICIL
  HOSES, CONNECTED TO THE SURFACE AIR COMPRESSOR
  TANK
• COMMUNICATION CABLE, LIFE LINE, PNEUMATIC
  FATHOMETER ARE ATTACHED TO THE DIVER
• SUITED FOR IN ADVERSE CONDITION HIGH STREAM
  VELOCITY, POLLUTED/TURBID WATER AND LONG
  DURATION/DETAILED INSPECTION
• UNLIMITED AIR SUPPLY
• SUSTAINED TIME 60 MINUTES AT 18m DEPTH

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• IS 10291-1982 LAID DOWN
• QUALIFICATION OF DIVERS AND SUPERVISORS
• SAFEGUARDS FOR THEIR WORKING

SAFEGUARDS FOR THEIR WORKING

• MINIMUM AGE 18 YEARS
• FITNESS BY DOCTOR IN LAST SIX MONTHS
• FITNESS TESTED FOR WORK AT REQUIRED DEPTH OR
  EQUIVALENT PRESSURE IN COMPRESSION CHAMBER
• KNOWLEDGE OF DIVING SIGNALS
• TRAINED FOR WORK IN NO VISIBILITY CONDITIONS AND
  0.6M DEPTH OF MUD AND CONDUCT SEARCH ETC.

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. CONTD SCUBA DIVING SAFE GUARDS FOR DIVERS)

• GOOD PHISIQUE,CAPABLE OF SUSTAINING STRAIN
• FREE FROM CARDIAC PROBLEM
• FREE FROM MID EAR PROBLEM ETC
• NOT ADDICTED TO ALCOHOL AND EXCESS SMOKING
• MORE THAN 45 YEARS NOT BE EMPLOYED FOR DEEP
  DIVING
• SELECT AGE gt30YEARS FOR TRAINING
• DIVERS DRESS,HELMET,COMPRESSED AIR AND
  ACCESSORIES
• STANDARD EQUIPMENTS

TOOLS REQUIRED

• VIDEO CAMERAS /CLOSE CIRCUIT TV CAMERAS AND TV
  MONITOR
• TELEMETRY LINK TO OPERATE CAMERA
• COMMUNICATION SYSTEM WITH AMPLIFIER AND LOUD
  SPEAKERS ETC
• UNDERWATER LAMP/HEAD LAMP

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TYPES OF INSPECTION AND INTENSITY LEVELS

• LEVEL I-VISUAL,TACTILE INSPECTION(ROUTINE
  INSPECTION)
• LEVEL II-DETAILED INSPECTION WITH PARTIAL
  CLEANING
• LEVEL III-HIGHLY DETAILED INSPECTION WITH NDT
• LEVEL I-INSPECTION
• GENERAL VISUAL ROUTINE INSPECTION
• COVERED OVER EXTERIOR SURFACE
• PROBING OVER SUBSTRUCTURE AND STREAMBED
• TO DETERMINE THE NEED FOR LEVEL II/III INSPECTION

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TYPES OF INSPECTION (Contd..)

• LEVEL II INSPECTION
• TO BE CONDUCTED BASED ON REPORT OF LEVEL I
  INSPECTION
• NEEDS CLEANING OF STRUCTURAL ELEMENT
• DETAILED INVESTIGATION OF SELECTED COMPONENTS
• ATLEAST 20 OF ALL UNDERWATER ELEMENTS TO BE
  COVERED
• SIMPLE INSTRUMENTS CALIPPERSE AND SCALE TO
  IDENTIFY EXTENT AND SEVERITY OF DAMAGE

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TYPES OF INSPECTION (Contd..)

• LEVEL III INSPECTION
• HIGHLY DETAILED INSPECTION OF A CRITICAL
  STRUCTURE OF STRUCTURAL ELEMENT
• INCLUDES EXTENSIVE CLEANING, DETAILED
  MEASUREMENTS
• SELECTED NDT/PARTIALLY DISTRUCTIVE TESTING SUCH
  AS ULTRASONIC, SAMPLE CORING, IN-SITU HARDNESS
  TESTING Etc..
• REQUIRES MORE EXPERINCE AND TRAINING

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UNDERWATER INSPECTION PROCEDURE

• INTIAL INSPECTION REQUIRES CAREFUL PLANNING
• PRIOR SITE SURVEY FOR SELECTION OF INSPECTION
  METHODS, TYPE AND INTENSITY LEVEL, EQUIPEMENT
  REQUIRED
• REVIEW OF AVAILABLE RECORDS AND PAST HISTORY
• AVAILABILITY OF TOOLS AND PLANTS
• ABILITY/QUALIFICATION OF DIVING TEAM
• SCOUR INVESTIGATION
• INSPECTION OF SUB STRUCTURE

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UNDERWATER INSPECTION PROCEDURE (Contd..)

• UNDERWATER NDT INSPECTION
• SOUNDING/SENSING DEVICE- FOR CHECKING SCOUR IN
  THE STREAM BED
• REBOUND HAMMER- SURFACE HARDNESS TESTER TO
  OBTAIN GENERAL CONDITION OF CONCRETE
• MAGNETIC REBAR LOCATION- TO DETERMINE THE
  LOCATION AND ORIENTATION OFREBAR
• ULTRASONIC SYSTEM FOR CONCRETE- TO CHECK
  UNIFORMITY OF CONCRETE FROM ONE LOCATION TO THE
  OTHER

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UNDERWATER NDT INSPECTION (Contd..)

• ULTRASONIC THICKNESS METRES TO MEASURE THE
  THICKNESS OF THE STEEL
• UW MAGNETIC PARTICLE TESTING TO DETECT SURFACE
  CRACKS
• RADIOGRAPHY TO DETECT INTERNAL DEFECTS/FLAWS

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PROCEDURE OF UNDER-WATER INSPECTION BY DIVERS

• LIST CHECK THE WORKING OF ALL TOOLS EQUIPMENT
• BOATS LIFE PRESERVERS AS REQUIRED
• CAMERAS
• INSPECTION DOCUMENTS, PAPER,CLIP BOARD PENCILS
• CONCRETE OR STEEL TOOL KIT AS APPLICABLE
• SOUNDING EQUIPMENT MARKING PENCILS(FOR SCOUR)
• SAFETY EQUIPMENT(ROPES, BUOYSMANNED SAFETY BOAT)

PROCEDURE FOR CHECKING PIERS FORMED OF PILES

• TWO DIVERS TO INSPECT SAME PILE.
• IF VISIBILITY IS POOR, PUT LIGHT CLOSE AND
  INSPECT
• DIFFERENT FACES AND TURN LATER TO UNINSPECTED
  SIDE

PROCEDURE FOR CONCRETE PIERS

• INSPECT CONDITION OF CONCRETE. TAKE PHOTOS AS
  REQD
• MEASURE DIMENSIONS OF SPALLS RECORD LOCATION
• INSPECT CRACKS AND MEASURE SIZE, LENGTHLOCATION

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DOCUMENTAION OF THE RESULTS OF U/W INSPECTION

• RECORD THE RESULTS OF UNDER-WATER INSPECTION
• IN THE PROFORMA PRESCIBED IN ANNEXURE-II,IIIIV
  OF
• BS-40 GUIDE LINES FOR U/W INSPECTION ISSUED BY
  RDSO

ACTION TO BE TAKEN ON RESULTS OF U/W INSPECTION

• MINOR DEFECTS SUCH AS CRACKS
• -AQUA RESINS FOR GROUTING REPLACING WATER
• CRACK gt6mm sand with grouting resins
• SPECIAL GROUTING EQUIPMENTS

SPALLING OF CONCRETE

• PREPARATION OF SURFACE BY WATER JET AT HIGH
  PRESSURE
• APPLYING THICK COAT OF EPOXY RESIN ON THE
  PREPARED SURFACE FOR BONDING
• EPOXY MORTAR

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REPAIR TECHNIQUES
FOR CONCRETE PILES

• JACKETING BY SHOTCRETE/GUNITE LAYER OF 75MM
  THICKNESS OR SO
• SHOTCRETE RING IS PREPARED ABOVE LOW WATER LEVEL
  AND LOWERED UPTO BOTTOM
• ANNULAR SPACE IS SUBSEQUENTLY GROUTED WITH MORTAR
  DISPLACING WATER

REPAIR BY UNDERWATER CONCRETING

• TREMIE CONCRETE
• BOTTOM OPENING SKIP BOX
• BAGGED CONCRETE
• GROUT INJECTION OF PREPLACED AGGREGATE

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TREMIE CONCRETE

• DESIGNED FOR LOW STREGTH UPTO M20
• SLUMP 150-200mm
• COHESIVE AND SHOULD NOT SEGREGATE DURING
  TRANSPORT OR PLACEMENT
• W/C RATIO lt0.5
• CEMENT CONTENT HIGH 400 KG/CUM

• PLASTICISERS FOR WORKABILITY
• TREMIE PIPE DIA 20MM AGRT-150MM
• 40MM
  200MM
• BOTTOM OF PIPE 300-400 MM IMMERSED IN CONCRETE
• MORE THAN 30 SQM AREA MORE THAN ONE PIPE
• IF MORE THAN ONE LIFT DIVERS TO PREPARE SURFACE
  BY REMOVING LAITANCE

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CASE STUDY OF Br. No.1201 ON SRR-MAQ SECTION ON
S.Rly
BRIDGE No.1201 AT Km.837/100-500 ON DOWN LINE ON
RIVER PYSAVALI WITH SPAN 3 x 30.48 18 x 15.24
SUPER STRUCTURE RIVETTED STEEL PLATE GIRDERS

• 1ST 3 SPANS ARE 100ON RIVETTED UNDERSLUNG GIRDERS

• NEXT 18 SPANS ARE 40 RIVETTTED PLATE GIRDERS

BEARINGS- 1ST 3 SPANS ROCKER ROLLER TYPE
REST ALL CENTRALLY ARTICULATED
SUB-STRUCTURE
PIERS 1,2,3, 5,7,9,11,13,15,17,19 A1 AND A2 ON
CR MASONRY
PIERS REST 4,6,8,10,12,14,16,18 AND 20 ARE MASS
CONCRETE
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FOUNDATION
WELL FOUNDATION WITH TWIN CIRCULAR MASONRY WELL
HISTORY OF THE BRIDGE
1.BRIDGE WAS BUILT IN 1906 AS 12 X 30.48 M UNDER
SLUNG RIVETTED PLATE STEEL GIRDER BRIDGE ON
ROCKER AND ROLLER BEARINGS, ON CRS MASONRY
PIERS WITH STONE MASONRY TWIN CIRCULAR WELLS
2. DURING 1960-1970, THOUGH CLEAR RECORDS ARE
NOT AVAILABLE, 9 SPANS FROM 4TH TO 12TH ARE
DIVIDED AS 2 EACH MAKING BRIDGE AS 3x
30.4818x 15.24 WITH 18 SPANS WITH RIVETTED
PLATE GIRDERS BY PROVIDING 9 ADDITIONAL MASS
CONCRETE PIERS ON CR MASONRY TWIN CIRCULAR
WELL FOUNDATION REASONS FOR SUCH CHANGE IS
NOT DOCUMENTED
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OBSERVATIONS PRIOR TO IDENTIFICATION OF PROBLEM
ON Br1201

• FREQUENT ATTENTION TO CROSS-LEVEL NEAR P4
• (Right Rail low)

• FREQUENT MIS-ALIGNMENT ON-TO ONE SIDE

• NON-RETENTION OF RECTIFIED CROSS-LEVEL
  ALIGNMENT

ACTION TAKEN ON THE OBSERVATIONS

• INITIALLY FORTNIGHTLY THEN WEEKLY RECORDING OF
• PARAMETERS DONE. ON GETTING PROGRESSIVE CHANGE
• UNDER- WATER INSPECTION WAS ORDERED

• ON 20.02.2002 DIVERS INSPECTED THE SUB-STRUCTURE
  
• REPORTED THAT RH WELL STEINING OF P4 HAS A
  CAVITY
• 1.25 x 0.75 x 0.50 SIZE ON EAST SIDE JUST
  BELOW WELL CAP

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CONFIRMATION OF PROBLEM (IN MARCH-APRIL2002)

• SUBSEQUENT TO THE REPORT BY DEPARTMENTAL DIVERS
• EXPERT FROM CBE/O/MAS, SSE/BR DIVER WAS CALLED
• AND CAVITY AND ITS SIZE WAS GOT CONFIRMED.

PROGRAM FOR RECTIFICATION OF THE CAVITY

• BASED ON INSTRUCTIONS FROM CBE (HQ), DIVISION HAS
• CALLED TENDER FOR MICRO CONCRETING WORK UNDER
• WATER AND FIXED UP AN AGENCY BY 12.03.2003

• M/S DYANSOURE TREATMENT, MUMBAI IS THE AGENCY

• MICRO CONCERETING WITH ANTI-WAHSABLE,
  ANTI-SHRINKABLE PROPERTY USING RENDEROC UW OF
  FOSROC MAKE WAS ORDERED IN THE AGREEMENT ALONG
  WITH VIDEOGRAPHY OF UNDER WATER WORK

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TECHNICAL DETAILS OF MICRO-CONCRETING

• RENDEROC UW(UW STANDS FOR UNDER WATER) OF FOSROC
  MAKE IS A READY TO USE DRY POWDER, A MIXTURE OF
  PROCESSED CEMENT WITH ADDITIVES AND FINE
  AGGREGATES, WHICH IMPART IT CONTOLLED
  EXPANSION,WATER REDUCTION AND NON-WASHABLE
  PROPERTIES. THIS IS PACKED IN25 kg BAGS AND
  DOSAGE PER YIELD IS 14.5 LITRES PER 25 KG AT W/P
  0.22

• MICRO CONCRETE IS EXPECTED TO GIVE A CRUSHING
• STRENGTH OF 30 N/MM2 AFTER 7 DAYS

RENDEROC UW CAN BE USED IN ONE POUR FOR THICKNESS
UPTO 150 MM. FOR MORE, STONE AGGREGATE OF 2 TO 10
MM GRADED SHALL BE USED AT 11 RATIO

• 5.5 LITRES OF WATER IS TO BE ADDED FOR 25 KG BAG
  OF
• RENDEROC UW. CONCRETE MIXER TO BE USED FOR MIX

• RENDEROC PLUG IS THE PRODUCT USED TO SEAL JOINTS

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AGENCYS INPUTS FOR MICRO CONCRETING
MANPOWER FROM CONTRACTORS SIDE

• ONE CIVIL ENGINERING GRADUATE AS SITE ENGINEER
• ONE DIVER MATE (EX-NAVY) FOR MONITORING DIVING
• ONE EXPERT DIVER, 2 DIVERS 1 ASST. DIVER
• APART FROM ABOVE, 1 BOAT AND 12 MEN ENGAGED AS
• AND WHEN NEEDED FOR CONCRETING LOCALLY

TOOLS EQUIPMENT USED BY CONTRACTOR

• AIR COMPRESSOR DIESEL GENERATOR ALOGN WITH
• 3 DIVING EQUIPMENT
• VIDEO CAMERA FOR USING UNDER WATER, RECORDER
• WITH DISPLAY UNIT

MATERIALS USED FOR THE WORK
160 NO.S OF 25 KG RENDEROC UW BAGS, 20 NO.S OF
PLUG IN 5 KG BAGS, 200 No.S 25 KG 6MM AGGREGATE
BAGS ETC
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MODUS OPERANDI OF MICRO CONCRETING

• PHASE-1-INITIAL INSPECTION AND VIDEO RECORDING

• PHASE-2-CLEANING AND PREPARATION OF SURFACE

• PHASE-3 ASSESSMENT OF QUANTITY

• PHASE-4 SHUTTERING / FIXATION OF FORM WORK

• PHASE 5 MICRO CONCRETING

• SAND BAGS WERE USED TO SUPPORT SHUTTERING
• MS ANGLES AND TIES WERE USED TO SUPPORT GI
  SHUTTER
• JOINT BETWEEN SHUTTER SHEET AND STRUCTURE WAS
• SEALED WITH RENDEROC PLUG
• TREMIE WAS MANUFACTURED WITH PLASTIC HOSE PIPE
• FOR POURING CONCRETE INTO CAVITY. COMPACTION WAS
• DONE USING RODS. DIVERS ENSURED PROPER PLACEMENT
• CONCRETING COMPLETED IN 3 DAYS

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EXPERIENCES AND SUGGESTIONS

• RENDEROC UW IS GOOD FOR UNDERWATER CONCRETING

• DIVERS WERE GOOD IN DIVING JOB BUT THEY HAVE VERY
• LITTLE KNOWLEDGE OF CIVIL/BRIDGE ENGINEERING

• SHUTTERING /POURING TECHNIQUES USED BY THE FIRM
• ARE NOT VERY SATISFACTORY TO BE UPGRADED

• VIDEO RECORDING IS NOT ABLE TO THROW LIGHT FOR
• THE PURPOE, IT IS INTENDED. LOCATIONS SHALL BE
• GIVEN WITH METAL STRIP LIKE IDENTIFICATION MARKS

• AN ACTUAL 7 DAY CRUSHING STRENGTH OF 44 M/MM2
• WAS ACTUALLY ACHIEVED AGAINST ANTICIPATED 30 N

• COST CAN BE BROUGHT DOWN WITH WIDE USE OF THESE
• PRODUCTS.

• PERFORMANCE TILL DATE IS SATISFACTORY.

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CONCLUSIONS

• SYSTEMATIC AND SCIENTIFIC UNDERWARTER BRIDGE
  INSPECTION ARE VERY IMPORTANT IN BRIDGE
  MAINTENANCE AND MANAGEMENT
• THE SIGNIFICINT DAMAGE ENCOUNTER TO THE BRIDGE
  CAN BE AVOIDED BY CARRYING OUT UNDERWATER
  INSPECTION IN TIME

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