inspection and maintenance of steel girders-2

8/12/2019 Inspection and Maintenance of Steel Girders-2

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5.1.1 Foot OverBridges5.1.2 Road OverBridges

5.1.3 Track Bridges5.2 Inspection of steel girder

5.3 Cleaning and greasing of bearings

5.4 Protective painting of steel girder

5.4.1 Metallising5.4.2 Epoxy painting

5.4.2.1 Scheme of epoxy based paint5.4.3 Oil painting

5.5 Replacement of loose rivets

5.6 Repairs to welded joint

5.7 Strengthening of steel girder5.7.1 Common methods of strengthening

5.8 Replacement of corroded rivets

5.9 Conclusion

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LIST OF ABREVIATIONS

BB&CI Rly Bombay Baroda and Central India Railway

BBJ & Co Braith Waite Burn and Jessop Company

BFR Bogie Flat type for Rails

BG Broad Gauge

BGBL Broad Gauge Branch Line

BGML Broad Gauge Main Line

BN Rly Bengal Nagpur RailwayCBE Chief Bridge Engineer

CDA Coefficient of Dynamic Augment

CECRI Central Electro Chemical Research Institute

DA Dynamic Augment

DFT Dry Film Thickness

DL Dead Load

DPT Dye Penetration Test

EI Rly East Indian Railway

EUDL Equivalent Uniformly Distributed Load

FOB Foot Over Bridge

GIP Rly Great Indian Peninsular Railway

HML Heavy Mineral Loading

HSFG High Strength Friction Grip

IRBM Indian Railway Bridge Manual

IRC Indian Road Congress

IRS Indian Railway Standard

IS Indian Standard

JE Junior Engineer

km KilometrekN Kilo Newton

kmph kilometer per hour

LG Light Gauge


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( x i )

LL Live Load

m Metre

MBG Modified Broad Gauge

MG Meter Gauge

MGML Metre Gauge Main Line

mm Millimetre

MMAW Manual Metal Arc Welding

MMG Modified Metre Gauge

MS Mild Steel

MSM Rly Madras Southern Maratha Railway

NDT Non Destructive Testing

NG Narrow Gauge

ODC Over Dimensional Consignment

PSC Pre-stressed Concrete

PTFE Poly Tetra Fluoro EthyleneRBG Revised Broad Gauge

RCC Reinforced Cement Concrete

RDSO Research Design & Standards Organisation

RH Girder Restricted Height Girder

RL Rail Level

Rly Railway

ROB Road Over Bridge

RSJ Rolled Steel Joint

RUB Road Under Bridge

SAW Submerged Arc Welding

SBC Substructure Bridge Code

SE Section Engineer

t tonnesUSFD Ultra Sonic Flaw Detection

WDM Water Bound Macadam


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CHAPTER - 1

INTRODUCTION

Ever since the 1st railway train was hauled in April 1853 by asteam engine over a stretch of 33 Km track between BombayVictoria Terminus to Thane, Railways in India have never lookedback and have continued with their achievements withaccelerated pace. As on date we have about 63,465 route km ofrailway track network throughout the length and breadth of thecountry.

Building of a railway track over various stretches of landcris-crossing different cities, districts and states all over,necessarily involves tremendous earthwork, rock cuttings,tunneling and bridging. Out of these vital prerequisites, bridging isthe most intricate and multifaceted constituent in the railwaytrack requiring a precise and exhaustive exercise in its planning

and execution, considering its probable repercussions on theentire railway system for long years.

Number of bridges on Indian Railways as on date are to the tuneof about 1.21 lakhs belonging to the various types and lengthsand in different categories.

With the inception of railway transport system in India the

railway traffic was handled by different companies such as GIPRly., BN Rly., El Rly., MSM Rly., BB & Cl Rly., etc. In addition,various princely states formed their own railway network with theavailable technical know-how and resources as obtained in thosedays. Hence each system followed its own gauge and standard.However, as far as the type of gauge is concerned we had onlyfour types of gauge namely, B.G., M.G., N.G. and L.G. But thecriteria for bridges adopted was different depending on the

technology and material as obtained in those days.

But all the same a sort of similarity appears to have beenmaintained in designing and construction of these bridges, maybe by interaction between various construction agencies at


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various places and locations throughout the country.

Broadly speaking, the bridges in the early days of the railwaysystem were mostly based on steel structures shipped fromBritish Railways to India and after cannibalising in railwayworkshops and placing them in the track as super-structures forwhich suitable substructures out of stone or brick masonry piersand abutments or steel piles for piers and abutments wereconstructed. As the loads to be hauled initially were quite low,the sizes of substructures and girders were also less massive.

The bridge superstructures in the form of steel girders are either(1) beam type -(plate girders) or (2) truss type (open web). Themetal used in the fabrication of these girders was mostly wroughtiron based on the technology as obtained in those days. Thisperiod is roundabout earlier to 1885. These girders were eitherfabricated in England or released from British Railways andtransported to India by ship and after due modifications in railway

workshops in India were placed in track. Since these wereshipped from England to India, the despatch list accompanyingthe material was named as Shipping list. This nomenclatureholds good even today for despatch list of materialaccompanying the girders from railway workshops to varioussites.

Some of the early workshops known as Girder FabricationWorkshops were established at Manmad and Mugalsarai. Thetranshipped girders and structures were strengthened/modified inthese workshops to suit the extant loading standard anddimensions and put in the road wherever needed.

As the steel technology developed over the years and as therailways began expanding in a big way especially afterindependence in 1947, a dire need was felt to undertakefabrication of these girders on a huge scale during the

successive five year plans for various new construction lines aswell as for regirdering programmes. With this in view thefabrication of these steel girders was undertaken in railwayworkshops at Manmad, Mugalsarai and other railway workshops.


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After 1960 these workshops started fabricating open web girdersalso. As on date railway workshops fabricate girders of spans

ranging from 9.15m length to 76.2m length, (9.15, 12.2, 18.3,24.4m spans being plate girders and 30.5m, 45.7m, 61.0m and76.2m spans being open web through girders and also 30.5munderslung deck girders).

In addition a few spans of 91.4m and 122.2m have beenfabricated and erected by M/s. BBJ & Co. of Calcutta. CivilEngineering Workshop Manmad had also fabricated 3 nos.122.2m welded open web through spans, for Konkan RailwayCorporation in the year 1995.

After 1980 welded construction is being adopted for fabrication ofplate girders (open deck), open web girders and compositegirders (ballasted deck) of track bridge. Steel being an idealmetal for fabrication of railway bridge girders due to its tensileand compressive strengths being more or less equal, it isextensively used for railway bridge girders. Moreover before final

failure, it generally gives sufficient warning to the maintenanceengineer in the form of loss of camber, thus avoiding suddenfailure.

1.1 TYPES OF STEEL GIRDERS

In the early days, the railway track bridge- steel girders were ofthe following types :

1) Duplicated channels with longitudinal sleepers to carry

the track.2) Duplicated beams with cross sleepers to carry thetrack.3) Wide flange beam girders.4) Fish belly type girders, single or duplicated, called

beams of uniform strength.5) Pin connected triangulated type--Single or duplicated.6) N type open web deck girders7) Whipple through girders

8) Howe type through truss9) Pratt type through truss10) Camel back truss11) Baltimore through truss


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1676

250

1676

300

1676

1200

Fig. 1.1 DUPLICATE CHANNEL GIRDER(FOR SPAN UPTO 2.4 m)

Fig. 1.3 WIDE FLANGE BEAM GIRDER

Fig. 1.2 DUPLICATE BEAM WITH CROSS SLEEPERS(FOR SPAN UPTO 3.6 m)


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ELEVATIO

N

FIG.1.4FISH

BELLY

GIRDERS

(SINGLE

OR

DUPLIC

ATE)

SECTIO

N

X-X

(SINGLE)

SECTION

X-X

(DUP

LICATE)

X X


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Fig. 1.5 PIN CONNECTED TRIANGULATED TRUSS

Fig. 1.6 N TYPE TRUSS

Fig. 1.7 WHIPPLE TRUSS

Fig. 1.8 HOWE TRUSS

Fig. 1.9 PRATT TRUSS


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Fig. 1.10 CAMEL BACK TRUSS

Fig. 1.11 BALTIMORE TRUSS

Fig. 1.12 WARREN TRUSS

THROUGH TRUSS PONY TRUSS

Fig. 1.14

DECK TRUSS

Fig. 1.13 K TRUSS

inspection and maintenance of steel girders-2

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