UNDERWATER INSPECTION OF BRIDGES ILLUSTRATED WITH CASE STUDYBY Shri.K.Simon, Dy.CE/C/SCR Shri Mohd. Bakhsh, Dy.CE/W/WRShri .A.Raj Kumar, DEN/SR

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-MATURETO PREVENT ANY POSSIBLEMISHAP DUE TO STRUCTUREFAILURE BY TIMELY ACTION

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 WATERWHAT SHALL BE INSPECTED IN UW INSPECTION?CAVITY IN MASONRY /CONCRETEJOINTS IN MASONRY /CONCRETELOOSE/ MISSING STONE/BRICKS IN MASONRYWEATHERING OF MASONRYEXPOSURE OF REINFORCEMENT

WHAT SHALL BE INSPECTED IN UW INSPECTION? (CONTD)RUST STAINING, CRACKING, SPALLING, ABRASION, DISINTEGRATION IN CONCRETE STRUCTURESBULGING IN SUB STRUCTURESTEEL WORKS--CI PIPES-- STEEL CAISSONS-- SCREW PILESCORRECT LOCATION AND IDENTIFICATION OF DEFECTS IS IMPORTANT

Anerobic Bacterial Growth

Scaling of concrete

Spalling of concrete

Disintegration of concrete

Deep Cavitation

WHO WILL DO UNDER-WATER INSPECTION? ONLY WELL TRAINED PERSONNELPRACTICAL 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 ASPECTAFTER 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

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

METHODS OF PERFORMING UNDER-WATER INSPECTION

2.SCUBA -SELF CONTAINED UNDERWATER BREATHING APPRATUS 3. SURFACE SUPPLIED AIR DIVING OR MIXED GAS DIVING4.DEEP SEA DIVING NOT USED FOR BRIDGE INSPECTIONSCUBA DIVINGSCUBA DIVER IS PROVIDED WITH PORTABLE AIR SUPPLY & IS CONNECTED TO SURFACE THROUGH AN UMBILICAL CABLEMIN.EQUIPMENT ARE SCUBA, LIFE PRESERVER,WEIGHT BELT, KNIFE,FACE MASK AND SWIM FINS1.WADING INSPECTION BASIC, REGULAR METHID OF INSPECTION PROBING/SOUNDING ROD

. CONTD SCUBA DIVING)IS SUITED WHEN MANY DIVES OF SHORT DURATION ARE NEEDED & MOBILITY IS THE PRIME CONSIDERATIONMERITS ARE RAPID DEPLOYMENT, PORTABILITY, MIN. SUPPORT AND EXCELLENT MOBILITYDEMERITS ARE DEPTH LIMITATION, MIN.AIR SUPPLY LACK OF VOICE COMMUNICATION FROM SURFACEMAX. SUSTAINED TIME AND DEPTH IS ONE HOUR @18 M DIVING TEAM SHOULD HAVE 3 MEN & BOAT IS REQUIRED

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 DIVERSUITED FOR IN ADVERSE CONDITION HIGH STREAM VELOCITY, POLLUTED/TURBID WATER AND LONG DURATION/DETAILED INSPECTIONUNLIMITED AIR SUPPLYSUSTAINED TIME 60 MINUTES AT 18m DEPTH

IS 10291-1982 LAID DOWN QUALIFICATION OF DIVERS AND SUPERVISORSSAFEGUARDS FOR THEIR WORKINGMINIMUM AGE 18 YEARSFITNESS BY DOCTOR IN LAST SIX MONTHSFITNESS TESTED FOR WORK AT REQUIRED DEPTH OR EQUIVALENT PRESSURE IN COMPRESSION CHAMBERKNOWLEDGE OF DIVING SIGNALS TRAINED FOR WORK IN NO VISIBILITY CONDITIONS AND 0.6M DEPTH OF MUD AND CONDUCT SEARCH ETC. SAFEGUARDS FOR THEIR WORKING

GOOD PHISIQUE,CAPABLE OF SUSTAINING STRAINFREE FROM CARDIAC PROBLEMFREE FROM MID EAR PROBLEM ETCNOT ADDICTED TO ALCOHOL AND EXCESS SMOKINGMORE THAN 45 YEARS NOT BE EMPLOYED FOR DEEP DIVING SELECT AGE >30YEARS FOR TRAININGDIVERS DRESS,HELMET,COMPRESSED AIR AND ACCESSORIESSTANDARD EQUIPMENTS. CONTD SCUBA DIVING & SAFE GUARDS FOR DIVERS)VIDEO CAMERAS /CLOSE CIRCUIT TV CAMERAS AND TV MONITORTELEMETRY LINK TO OPERATE CAMERA COMMUNICATION SYSTEM WITH AMPLIFIER AND LOUD SPEAKERS ETCUNDERWATER LAMP/HEAD LAMPTOOLS REQUIRED

TYPES OF INSPECTION AND INTENSITY LEVELS

LEVEL I-VISUAL,TACTILE INSPECTION(ROUTINE INSPECTION)LEVEL II-DETAILED INSPECTION WITH PARTIAL CLEANINGLEVEL III-HIGHLY DETAILED INSPECTION WITH NDTLEVEL I-INSPECTIONGENERAL VISUAL ROUTINE INSPECTIONCOVERED OVER EXTERIOR SURFACEPROBING OVER SUBSTRUCTURE AND STREAMBEDTO DETERMINE THE NEED FOR LEVEL II/III INSPECTION

TYPES OF INSPECTION (Contd..)

LEVEL II INSPECTIONTO BE CONDUCTED BASED ON REPORT OF LEVEL I INSPECTIONNEEDS CLEANING OF STRUCTURAL ELEMENTDETAILED INVESTIGATION OF SELECTED COMPONENTS ATLEAST 20% OF ALL UNDERWATER ELEMENTS TO BE COVEREDSIMPLE INSTRUMENTS CALIPPERSE AND SCALE TO IDENTIFY EXTENT AND SEVERITY OF DAMAGE

TYPES OF INSPECTION (Contd..)LEVEL III INSPECTIONHIGHLY DETAILED INSPECTION OF A CRITICAL STRUCTURE OF STRUCTURAL ELEMENTINCLUDES EXTENSIVE CLEANING, DETAILED MEASUREMENTSSELECTED NDT/PARTIALLY DISTRUCTIVE TESTING SUCH AS ULTRASONIC, SAMPLE CORING, IN-SITU HARDNESS TESTING Etc..REQUIRES MORE EXPERINCE AND TRAINING

UNDERWATER INSPECTION PROCEDUREINTIAL INSPECTION REQUIRES CAREFUL PLANNINGPRIOR SITE SURVEY FOR SELECTION OF INSPECTION METHODS, TYPE AND INTENSITY LEVEL, EQUIPEMENT REQUIREDREVIEW OF AVAILABLE RECORDS AND PAST HISTORYAVAILABILITY OF TOOLS AND PLANTSABILITY/QUALIFICATION OF DIVING TEAMSCOUR INVESTIGATIONINSPECTION OF SUB STRUCTURE

UNDERWATER INSPECTION PROCEDURE (Contd..)UNDERWATER NDT INSPECTION SOUNDING/SENSING DEVICE- FOR CHECKING SCOUR IN THE STREAM BEDREBOUND HAMMER- SURFACE HARDNESS TESTER TO OBTAIN GENERAL CONDITION OF CONCRETEMAGNETIC REBAR LOCATION- TO DETERMINE THE LOCATION AND ORIENTATION OFREBARULTRASONIC SYSTEM FOR CONCRETE- TO CHECK UNIFORMITY OF CONCRETE FROM ONE LOCATION TO THE OTHER

UNDERWATER NDT INSPECTION (Contd..)ULTRASONIC THICKNESS METRES TO MEASURE THE THICKNESS OF THE STEELUW MAGNETIC PARTICLE TESTING TO DETECT SURFACE CRACKSRADIOGRAPHY TO DETECT INTERNAL DEFECTS/FLAWS

PROCEDURE OF UNDER-WATER INSPECTION BY DIVERSLIST &CHECK THE WORKING OF ALL TOOLS &EQUIPMENTBOATS & LIFE PRESERVERS AS REQUIREDCAMERASINSPECTION DOCUMENTS, PAPER,CLIP BOARD &PENCILSCONCRETE OR STEEL TOOL KIT AS APPLICABLESOUNDING EQUIPMENT &MARKING PENCILS(FOR SCOUR)SAFETY EQUIPMENT(ROPES, BUOYS&MANNED SAFETY BOAT)PROCEDURE FOR CHECKING PIERS FORMED OF PILESTWO DIVERS TO INSPECT SAME PILE.IF VISIBILITY IS POOR, PUT LIGHT CLOSE AND INSPECT DIFFERENT FACES AND TURN LATER TO UNINSPECTED SIDEPROCEDURE FOR CONCRETE PIERSINSPECT CONDITION OF CONCRETE. TAKE PHOTOS AS REQDMEASURE DIMENSIONS OF SPALLS &RECORD LOCATIONINSPECT CRACKS AND MEASURE SIZE, LENGTH&LOCATION

DOCUMENTAION OF THE RESULTS OF U/W INSPECTIONRECORD THE RESULTS OF UNDER-WATER INSPECTION IN THE PROFORMA PRESCIBED IN ANNEXURE-II,III&IV OF BS-40 GUIDE LINES FOR U/W INSPECTION ISSUED BY RDSOACTION TO BE TAKEN ON RESULTS OF U/W INSPECTIONMINOR DEFECTS SUCH AS CRACKS-AQUA RESINS FOR GROUTING REPLACING WATERCRACK >6mm sand with grouting resinsSPECIAL GROUTING EQUIPMENTSPREPARATION OF SURFACE BY WATER JET AT HIGH PRESSUREAPPLYING THICK COAT OF EPOXY RESIN ON THE PREPARED SURFACE FOR BONDINGEPOXY MORTARSPALLING OF CONCRETE

JACKETING BY SHOTCRETE/GUNITE LAYER OF 75MM THICKNESS OR SOSHOTCRETE RING IS PREPARED ABOVE LOW WATER LEVEL AND LOWERED UPTO BOTTOMANNULAR SPACE IS SUBSEQUENTLY GROUTED WITH MORTAR DISPLACING WATERREPAIR TECHNIQUESFOR CONCRETE PILESTREMIE CONCRETEBOTTOM OPENING SKIP BOXBAGGED CONCRETEGROUT INJECTION OF PREPLACED AGGREGATEREPAIR BY UNDERWATER CONCRETING

DESIGNED FOR LOW STREGTH UPTO M20SLUMP 150-200mmCOHESIVE AND SHOULD NOT SEGREGATE DURING TRANSPORT OR PLACEMENTW/C RATIO =

CASE STUDY OF Br. No.1201 ON SRR-MAQ SECTION ON S.RlyBRIDGE No.1201 AT Km.837/100-500 ON DOWN LINEON RIVER PYSAVALI WITH SPAN 3 x 30.48+ 18 x 15.241ST 3 SPANS ARE 100ON RIVETTED UNDERSLUNG GIRDERSSUPER STRUCTURE RIVETTED STEEL PLATE GIRDERS NEXT 18 SPANS ARE 40 RIVETTTED PLATE GIRDERSBEARINGS- 1ST 3 SPANS ROCKER & ROLLER TYPE REST ALL CENTRALLY ARTICULATEDSUB-STRUCTUREPIERS 1,2,3, 5,7,9,11,13,15,17,19 & A1 AND A2 ON CR MASONRYPIERS REST 4,6,8,10,12,14,16,18 AND 20 ARE MASS CONCRETE

FOUNDATIONWELL FOUNDATION WITH TWIN CIRCULAR MASONRY WELLHISTORY OF THE BRIDGE1.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 WELLS2. DURING 1960-1970, THOUGH CLEAR RECORDS ARE NOT AVAILABLE, 9 SPANS FROM 4TH TO 12TH ARE DIVIDED AS 2 EACH MAKING BRIDGE AS 3x 30.48+18x 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

OBSERVATIONS PRIOR TO IDENTIFICATION OF PROBLEM ON Br1201FREQUENT ATTENTION TO CROSS-LEVEL NEAR P4(Right Rail low) FREQUENT MIS-ALIGNMENT ON-TO ONE SIDE NON-RETENTION OF RECTIFIED CROSS-LEVEL & ALIGNMENTACTION 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

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 CAVITYBASED 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 AGENCYMICRO 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

TECHNICAL DETAILS OF MICRO-CONCRETINGRENDEROC 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 DAYSRENDEROC 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 1:1 RATIO5.5 LITRES OF WATER IS TO BE ADDED FOR 25 KG BAG OF RENDEROC UW.& CONCRETE MIXER TO BE USED FOR MIXRENDEROC PLUG IS THE PRODUCT USED TO SEAL JOINTS

AGENCYS INPUTS FOR MICRO CONCRETINGMANPOWER FROM CONTRACTORS SIDEONE CIVIL ENGINERING GRADUATE AS SITE ENGINEERONE DIVER MATE (EX-NAVY) FOR MONITORING DIVINGONE EXPERT DIVER, 2 DIVERS & 1 ASST. DIVERAPART FROM ABOVE, 1 BOAT AND 12 MEN ENGAGED AS AND WHEN NEEDED FOR CONCRETING LOCALLYTOOLS & EQUIPMENT USED BY CONTRACTORAIR COMPRESSOR & DIESEL GENERATOR ALOGN WITH 3 DIVING EQUIPMENTVIDEO CAMERA FOR USING UNDER WATER, RECORDER WITH DISPLAY UNITMATERIALS USED FOR THE WORK160 NO.S OF 25 KG RENDEROC UW BAGS, 20 NO.S OF PLUGIN 5 KG BAGS, 200 No.S 25 KG 6MM AGGREGATE BAGS ETC

MODUS OPERANDI OF MICRO CONCRETINGPHASE-1-INITIAL INSPECTION AND VIDEO RECORDINGPHASE-2-CLEANING AND PREPARATION OF SURFACEPHASE-3 ASSESSMENT OF QUANTITYPHASE-4 SHUTTERING / FIXATION OF FORM WORKPHASE 5 MICRO CONCRETINGSAND BAGS WERE USED TO SUPPORT SHUTTERINGMS ANGLES AND TIES WERE USED TO SUPPORT GI SHUTTERJOINT BETWEEN SHUTTER SHEET AND STRUCTURE WAS SEALED WITH RENDEROC PLUGTREMIE 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

EXPERIENCES AND SUGGESTIONSRENDEROC UW IS GOOD FOR UNDERWATER CONCRETINGDIVERS WERE GOOD IN DIVING JOB BUT THEY HAVE VERY LITTLE KNOWLEDGE OF CIVIL/BRIDGE ENGINEERINGSHUTTERING /POURING TECHNIQUES USED BY THE FIRM ARE NOT VERY SATISFACTORY & TO BE UPGRADEDVIDEO RECORDING IS NOT ABLE TO THROW LIGHT FOR THE PURPOE, IT IS INTENDED. LOCATIONS SHALL BE GIVEN WITH METAL STRIP LIKE IDENTIFICATION MARKSAN ACTUAL 7 DAY CRUSHING STRENGTH OF 44 M/MM2 WAS ACTUALLY ACHIEVED AGAINST ANTICIPATED 30 NCOST CAN BE BROUGHT DOWN WITH WIDE USE OF THESEPRODUCTS.PERFORMANCE TILL DATE IS SATISFACTORY.

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

Thank you

UNDERWATER INSPECTION OF BRIDGES ILLUSTRATED BY CASE STUDIESLOOSE/MISSING STONE/BRICK IN MASONRY