summar training report on open web girder done in railway

1. 1
PROJECT REPORT
OPEN WEB GIRDER & SOIL TESTING
BY :- UNDER THE GUIDENCE :-
ALANKAR JAISWAL MR. VIKRAMAA PRASAD
B.TECH, 3rd
year S.S.E./DRAWING
CIVIL ENGINEERING ………………………………………

2. 2
ACKNOWLEDGEMENT
It would be insufficient just to say a “word of thanks” for all
those people who have been so instrumental in the success of
this project.
We are grateful to Mr. VIKRAMAA PRASAD, Senior Section
Engineer/Drawing who has guided us right through the study
of this project. It is due to his efforts that my project has
gained its present stature and I can never thank him enough
for all he has done.

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OPEN WEB GIRDER

4. 4
INTRODUCTION
 Indian Railways are having about 1.27 lac bridges out of which about 16000
are steel girder bridges.
 Mostly all steel bridges of span 30.5 meters and aboveare of open web
type.
 Open web girders are used as through standard spans of 30.5, 45.7, 61.0
and 76.2 meters.
 Warren truss (triangulated truss) with vertical members at every panel
point is used as standard truss for thesegirders.
 As a standard practicecamber is provided in steel girder bridges to offset
the effect of deflection under moving load.
 In addition to camber, prestressing of truss members is done to counter the
stresses likely to develop under actual loads.
 This paper briefly summarizes theconcepts and the existing design
provisions for cambering & prestressing.

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SALIENT FEATURES OF OPEN
WEB GIRDER
RDSO Drg No. BA – 11461 to BA – 11479 (M.B.G. Standard)
Weight of girder – 65 MT
Overalllength of girder – 32.460m
Effective length of girder – 31.926m (Center to center of Bearings)
Height of girder – 7.637m
Width of girder – 5.760mTypeof loading – MBG Loading
FLOW PROCESS CHART FOR
FABRICATING OPEN WEB GIRDER

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TEMPLATING
A. Need for Templating
There are nominal & camber dimensions in RDSO drawings for Open
Web Girders. It is not possible to show all details at intersection points
of components, hence the drawing is laid in 1:1 scale on shop floor
which is termed as Templating. It’s needs for achieving the following
objectives:
1. Obtaining the missing dimensions and infringements at
intersection points.
2. To check correctness of camber by verifying the closing lengths.
3. For obtaining the correct profile of all Gusset plates and preparing
Master gussets for manufacturing of jigs for components/ members at
the each panel points/joints.
B. TEMPLATING OF PROCESS
1.All the Gusset plates are marked with nominal dimensions.
2. The central vertical is marked as Normal.
3. All other lengths are marked as per camber length.
4. Cutting list is prepared as per the dimensions obtained from the
camber diagram.

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MANUFACTURINGOF MASTERS AND JIGS
 Transferring of intersection lines on Master plates from templating.
 Detail of field holes and intersection marking on Master plates as per Drgs.
 Drilling of Masters and Jig plates.
 Manufacturing of Masters and Jigs of main components & small fitting.

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CUTTING OF MATERIEAL
 Inspection by PCO before cutting of Raw Material as per codal provisions
required as per Drgs and IS: 2062 & IS: 1852
 Straightening of deformed sections of raw material.
 Reference marking, Gauge lines marking for Jig filling of components,
Inspection by PCO before Master and Jig drilling.

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JIG FILLING
 All the required material to be filled in Jig and Fixtures after surface
cleaning, edge preparation and tacking no of components (bunch) to
facilitate further process.
 Drilling of components in bunches through jig to increase the outputs of
productas well as achieve interchangeability.
 Easy handling of number of components to other shops for further
activities.

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INITIAL ASSEMBLY
 Second drilling of components if required when left over the holes in jig
section.
 De-linking (bunch of plates/member) of the tack members from jigs and
fixtures.
 Surfacecleaning around the holes and painting of one coat of basecoat
after taking out of member fromJig and Fixtures.
 Initial assembly after painting of hidden surfaceand Riveting as whole.
 Edge milling of main components.
 End finishing of components.
 Internalinspection of all components.
 In welded girder, shop welding in made by SAW.

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RDSO INSPECTION
 Inspection by M & C wing for welding quality and procedure.
 Inspection by Structuralwing for structuralwork.
 Before painting/Metalizing all components of open web girder are to be
offered for inspection by RDSO as per Fabrication Specification B1-2001 and
Welded Bridge code IRS-2001
A. INSPECTION BY M & C WING FOR WELDING QUALITY AND
PROCEDURE
1. Visual inspection
2. Mechanical inspection
3. Non destructive test
a. Magnetic particle inspection
b. Ultra sonic test
c. Radiographic test
d. Dyepenetrate test
4. Destructivetest
a. Macro etching test
B. INSPECTION BY STRUCTURAL WING FOR WELDING QUALITY AND
PROCEDURE
1. Overalllength of member
2. Distance of center of bearings
3. Depth of girder
4. Diagonal length
5. Center of intersection of angles
6. Butting of members
7. Straightness of girder
8. Checking of weld profile as dye penetration test
9. Pitch of holes
10.Distance between inner to inner holes
11.Distance between outer to outer holes
12.Edge of distance
13.Box width of member
14.Quality of rivets

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METALIZING/PAINTING
 Metalizing and painting of components and stenciling of shipping marks
followed as per Metalizing & painting scheduleIRS: B1-2001 AppendixVII.
 Surfacepreparation for metalizing as per SA 2 ½ grade by grit blasting.
 Then followed by Metalizing process by metal spraying (Aluminumwire of
3-5 mm dia) by two passes.
 The nominal thickness of the coating shall be 150 microns. ( checking by
elcometre DFT)
 Then Etch primer to IS:5666 coatshallbe applied on aluminum coating.
 One coat of Zinc-chromeIS:104of thickness 25-30 microns shallbeapplied
 Followed by one coat of Aluminum paint IS: 2339 of 25-30 micron shallbe
applied.
 Final coating aluminum applied on site.

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IMPORTANT PROCESS
FLAME CUTTING
 Flame cutting by mechanically controlledtorch/torchesshall be accepted
both in the case of mild steel andhightensile steelwork. Providedthe
edge as givenby the torchis reasonably cleanand straight, plates may be
cut toshape and beams and other sections cut tolengthwitha gas cutting
torch, preferably oxyacetylene gas shouldbe used.
 All flame cut edges shall be ground toobtain reasonably cleansquare and
true edges. Draglines producedby flame cut should be removed.
 Unless machining has beenspecifically providedfor, special care is tobe
takento ensure that ends of all plates andmembers are reasonably in
close contact and the faces are at right angles tothe axis of the members
and joints, whenmade, are alsoreasonably in close contact.
 Multi headflame cutting machine usedfor the higher production.
SUBMERGED ARC WELDING
Major Uses
The submergedarc process is widely usedinheavy steel plate fabricationwork.
This includes the welding of structural shapes, the longitudinal seamof larger
diameter pipe, the manufacture of machine components for all types of heavy
industry, and the manufacture of vessels andtanks for pressure andstorage
use. It is widely usedin the shipbuilding industry for splicing andfabricating sub-
assemblies, andby many other industries wheresteels are usedinmediumto
heavy thicknesses. It is alsousedfor surfacing and buildup work, maintenance,
and repair.

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ADVANTAGE:-
The major advantages of the SAWor submergedarc welding process are:
 Highquality metal weld.
 Extremely highspeedanddepositionrate
 Smooth, uniformfinishedweldwithno spatter.
 Little or no smoke.
 No arc flash, thus minimal need for protective clothing.
 Highutilizationof electrode wire.
 Easy automationfor high-operator factor.
 Normally, no involvement of manipulative skills.

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SOIL TESTING

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INTRODUCTION
Simple soil tests are required for assessing quality of earthwork on Railway
projects. These tests play an important role in maintaining quality of earthwork
and thereby the performance of Railway formation. However, in field, while
conducting stage inspections on zonal railways, it has been observed that the
testing procedures vary which affects the soil testing results thereby affecting
the quality of work done.

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SOIL TESTING
 SIEVE ANALYSIS
 STANDARD COMPACTION TEST
 DIRECT SHEAR TEST
 ATTERBERG LIMITS TEST
In Atterberg limit test have three type of testing:
(1) Liquid limit test
(2) Plastic limit test
(3) Shrinkage limit test

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SIEVE ANALYSIS
There is large variation in types of soils from site to site. Accordingly, their
behavior has alsovariation. To make understanding of soil in easy manner, their
grouping has been done depending on size of soil particles and their water
absorption capacity. Ratio of soil of different sizes are worked out from sieve
analysis and hydrometer/laser particle analyzer and capacity to absorb water is
worked out from liquid limit, plastic limit tests. These test are used to classify
the soils. Sieving is used for gravel as well as sand size particles and
sedimentation procedures are used for finer soils. For soils containing coarse
and fine soil particles both, it is usual toemploy bothsieving and sedimentation
procedures.
APPARATUS
1. Set of fine IS sieves 2 mm, 600μ, 425μ, 212μ, and 75μ
2. Set of coarse sieves 20 mm, 10 mm and 4.75 mm.
3. Weighing balance, with accuracy of 0.1% of the mass of sample
4. Oven
5. Mechanical shaker
6. Mortar, with rubber pestle
7. Brushes
8. Trays

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PROCEDURE
 The dried sample is taken in tray and soaked with water and mixed 2 g of
sodium hexametaphosphate of 2 g or sodiumhydroxide of 1 g and sodium
carbonate of 1 g per liter of water added as dispersive agent. The soaking
of soil continued for 10 -12 hours.
 Sample is washed through 4.75 mm IS sieve with water till substantially
clean water comes out. Retained sample on 4.75 mm IS sieve shall be
oven dried for 24 hours. This dried sample is sieved through 20 mm, 10
mm set of IS sieves.
 The portion of the passing 4.75 mm IS sieve shall be oven dried for 24
hours. This oven dried material is riffled and is taken of about 200 g.
 This sample of about 200 g is washed on 75 micron IS sieve with half litre
distilled water till substantially clear water comes out.
 The material retainedon75 μ IS sieve is collectedanddriedinoven at 105
- 120 ºC for 24 hours. The driedsoil sample is sievedthrough2 mm, 600 μ,
425 μ, 212 μ IS sieves. Soil retained on each sieve is weighed.
 If the soil passing 75 μ is 10% or more, hydrometer method is used to
analysis soil particle size.
Hydrometer Analysis
 Particles passed through 75 μ IS sieve along with water is collected and
put into a 1000 ml jar for hydrometer analysis. More water if required is
added to make the soil water suspension just 1000 ml. The suspension in
the jar is vigorously shakenhorizontally by keeping the jar in between the
palms of two hands. The jar is put on the table. A graduated hydrometer
is carefully inserted in to the suspension with minimum disturbance.
 At different time intervals, the density of the suspension at the c.g. of the
hydrometer is noted by seeing the depth of sinking of the stem. The

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temperature of suspension is noted for each recording of hydrometer
reading.
 Hydrometer reading is takenat a time of 0.5, 1.0, 2.0, 4.0, 15.0, 45.0, 90.0,
180.0 minutes, 6 hrs, 24 / 48 hours.
 By using the nomogram the diameter of the particles at different
hydrometer reading is found out. (Ref. IS : 2720 (Part 4) –1985, page 30).
After completing mechanical analysis andhydrometer analysis the
results are plotted on a semi log graph with particle size as abscissa (log
scale) and the percentage smaller thanthe specifieddiameter as ordinate.

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STANDARD COMPACTION TEST
Compaction is the process of densification of soil by reducing air voids.
The degree of compaction of a given soil is measured in terms of its dry
density. The dry density is maximum at the optimum water content. A
curve is drawn between the water content and dry density to obtain the
maximum dry density and optimum water content.
Dry density = M / V
1+ ω
where M = total mass of soil
V = volume of soil
ω = water content
APPARATUS
1. Cylindrical metal compaction mouldCapacity : 1000 cc with dia 100 mm
+ 0.12250 cc with dia 150 mm + 0.1
Internal diameter : 100 mm + 0.1150 mm + 0.1
Internal effective height of mould : 127.3 + 0.1 mm
Collar : 60 mm high Detachable base plate
2. Rammer Mass : for light compaction = 2.6 kg
heavy compaction = 4.9 kg
Dia : 50 mm
3. IS sieve : 19 mm & 4.75 mm
4. Oven: Thermostatically controlledtomaintaina temperature of 105 ºC
to 110 ºC.
5. Weighing Balance : sensitivity - 1 g for capacity 10 kg

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0.01g for capacity 200 g
6. Steel straight edge of about 300 mm in length with one edge levelled.
7. Gradation jar
8. Large mixing pan
9. Spatula
PREPARATION OF SAMPLE
1. A representativeportionof air dried soil sample (in case of oven drying
temp. < 60 ºC) break the clods, remove the organic matter like free roots,
piece of bark etc.
2. Take about 6 kg - (for soil is not susceptible to crushing during
compaction) 15 kg - (for soil is susceptible to crushing during compaction)
3. Sieve above material through 19 mm IS sieve and 4.75 mm IS sieve and
% passing 4.75 mm IS sieve. Donot usenthe soil retainedon20 mm sieve.
Determine the ratio of fraction retained and that passing 4.75 mm sieve.
4. If % passing retained on 4.75 mm IS sieve is greater than 20 mm IS
sieve, use the larger mould of 150 mm diameter.
5. Mix the soil sample retained on 4.75 mm sieve and that passing 4.75
mm sieve in the proportion determined.
6. Thoroughly mix water in
a) Sandy and gravely soil : 3 to 5 %
b) Cohesive soil : 12 to 16 % approx.
Store the soil sample in a sealed container for minimum period of 16
hours.
PROCEDURE

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1. Clean and dry the mould and base plate. And apply a thin layer of
grease on inside the mould.
2. Weighthe mould to the nearest 1 gram. Attach the collar to the mould
and place on a solid base.
3. Compact the moist soil in to the mould in five layers of approximately
equal mass, corri layer being given 25 blows from 4.9 kg rammer dropped
from the height of 450 mm above the soil. The blows should be
distributed uniformly over the surface of each layer.
4. Remove the collar and trim off the excess soil projecting above the
mould by using straight edge. Take the weight of mould with compacted
soil in it.
5. Remove the 100 g compacted soil specimen for the water content
determination.
6. Add water in increment of 1 to 2 % for sandy and gravely soils and 2 to
4 % for cohesive soils.
7. Above procedure will be repeated for each increment of water added.
The total number of determination shall be at least four and moisture
content shouldbe such that the OMC at whichMDD occurs , is within that
range.
PRECAUTION
1. Ramming should be done continuously taking of height of 450 mm free
fall accurately.
2. The amount of soil taken for compaction should be in such a way that
after compacting the last layer, the soil surface is not more than 5 mm
above the top rim of the mould.
3. Weighing should be done accurately.

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DIRECT SHEAR TEST
The Direct Shear test is carried out with an apparatus consisting of a square or
circular box divided into two halves. The specimen, contained in the box, is
subjected to a constant normal load while an increasing horizontal force is
appliedto one of the sections of the shear box. This force causes a shear failure
along the juncture between the box sections. The shear force and the normal
load are measured directly. The rate of strain is adjusted by the speed of the
horizontal force applied. The loading unit has V-Strips on which the shear box
housing rests.
The pre-calibratedloadyoke helps counter balance the loading system. The load
yoke with direct and through level system for applying normal load upto 8
Kg/cm2 capacity. Fixtures for proving ring, brackets for holding consolidation
and strain dial gauges are provided. The lead screw connected to the shear box
housing helps application of shear stress.
Shear strengthof the soil is its maximum resistance toshearing stress. The shear
strength is expressed as -
s = c’ + σ’ tan ø’
Where c’ = effective cohesion
σ’ = effective stress Ø’ = effective angle
APPARATUS
1. Shear box, divided into two halves by a horizontal plane and fitted with
locking and spacing screw.
2. Box container to hold the shear box.
3. Base plate having cross grooves on its top surface.
4. Grid plates perforated (2 nos.)
5. Porous stones 6 mm thick (2 nos.)

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6. Proving ring
7. Dial gauge accuracy 0.01 mm – 2 mm
8. Static compaction device, spatula.
9. Loading yoke, loading frame, loading pad.
PREPARATION OF SAMPLE
A) UNDISTURBED SAMPLE : Specimen is prepared by pushing a cutting ring of
size 10 cm dia and 3 cm high , in the undisturbed soil sample. The square
specimen of size 6 cm x 6 cm x 2.4 cm is then cut from circular specimen.
B) DISTURBED SAMPLE :
(a) cohesive soil :- the soil may be compacted to required density and moisture
content directly into the shear box after fixing the two halves of the shear box
together by mean of the fixing screw.
(b) cohesion less soil :- soil may be tamped in the shear box itself with base
plate and grid plate or porous stone as required in place at the bottom of the
box.
PROCEDURE
1. Measure the internal dimensionof the shear box and average thickness of the
grid plates
2. Fix the upper part of the box to the lower part using the locking screw. Attach
the base to the lower part .
3. Place the grid plate in the shear box keeping the serration’s of the grid at
right angle to the direction of shear. Place a porous stone over the grid plate.
4. Weight the shear box with base plate, grid plate and porous stone.
5. Place soil specimen in the box and weight the box.

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6. Place inside the box container and the loading pad on the box. Mount the box
container on the loading pad.
7. Bring the upper half of the box in contact with the proving ring. Check the
contact by giving slight movement.
8. Fill the container with water and mount the loading yoke on the ball placed
on loading pad.
9. Mount one dial gauge on the loading yoke to recordthe vertical displacement
and another dial gauge on the container to record the horizontal displacement.
10. Place the weight on loading yoke to apply a normal stress.
11. Allow the sample to consolidate under the applied normal stress. Note
reading of vertical displacement dial gauge.
12. Remove the locking screws. Using the spacing screws, raise the upper part
slightly above the lower part such as that gap is slightly larger than the
maximum particle size. Remove the spacing screws.
13. Adjust all dial gauges to read zero. The proving ring also read zero.
14. Apply the horizontal shear load at constant rate of strain.
15. Record reading of the proving ring, the vertical displacement dial gauge.
16. Continue the test, till the specimen fails or till a strain of 20 % is reached.
17. At the end of the test, remove the specimen from the box.
18. Repeat the test on identical specimens under the normal stress.

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ATTERBERG LIMITS TEST
 Liquid limit test
 Plastic limit test
 Shrinkage limit test
LIQUID LIMIT TEST
The Liquid limit of fine-grained soil is the water content at which soil behaves
practically like a liquid, bit has small shear strength. It flow close the groove in
just 25 blows in Casagrandes liquidlimit device. It is one of the Atterberg limits.
The Atterberg limitsconsistof The Liquid limit, Plastic limit and Shrinkage limit.
As it difficult to get exactly 25 blows in the test. 3 to 4 tests are
conducted, and the number of blows (N) required in each test determined. A
semi-log plot is drawn between log N and the water content (w).

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APPRATUS
1. Casagrande’s limit device
2. Grooving tools of both standard and ASTM types
3. Oven
4. Evaporating dish
5. Spatula
6. 425 micron IS sieve
7. Weighing balance with 0.01 g accuracy
8. Wash bottle
9. Air-tight andnon-corrodible container for determinationof moisture content.
PREPARATION OF SAMPLE
1. Air dry the soil sample (in case drying) and break the clods. Remove the
organic matter like tree roots, pieces of bark etc.
2. About 100 g of the specimen passing 425 micron IS sieve is mixed thoroughly
with distilled water in the evaporating dish and left for 24 hours for soaking.
PROCEDURE
1.A portion of the paste is placed in the cup of the Liquid limit device.
2. Level the mix so as to have a maximum depth of 1 cm.
3. Draw the grooving tool through the sample along the symmetrical axis of the
cup, holding the tool perpendicular to the cup.
4. For normal fine grainedsoil : The Casagrande tool is used which cuts a groove
of width 2 mm at the bottom, 11 mm at the top and 8 mm deep.

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5. For sandy soil : The ASTM tool is used which cuts a groove of width 2 mm at
bottom, 13.6 mm at top and 10 mm deep.
6. After the soil pat has been cut by proper grooving tool, the handle is rotated
at the rate of about 2 revolutions per second and the nos. of blows counted till
the two parts of the soil sample come into contact for about 10 mm length.
7. Take about 10 g of soil near the closed groove & find water content.
8. The soil of the cup is transferred to the dish containing the soil paste and
mixed thoroughly after adding a little more water. Repeat the test.
9. By altering the water content of the soil and repeating the foregoing
operations, obtain at least 5 readings in the range of 15 - 35 blows. Don’t mix
dry soil to change its consistency.
10. Liquid limit is determined by plotting a ‘flow curve’ on semi-log graph
between nos. of blows on logarithmic scale and water content on arithmetical
scale.
11. Generally these points lie in a straight line.
12. Water content corresponding to 25 blows is the value of Liquid limit.
PLASTIC LIMIT TEST
The Plastic limit of a fine-grained soil is the water content of the soil below
which it ceases to be plastic. It begins to crumble when rolled in to threads of 3
mm diameter. It is the boundary betweenLiquidand Plastic limit. It is one of the
Atterberg limits. The Atterberg limits consist of The Liquidlimit, Plastic limit and
Shrinkage limit.
APPARATUS
1. Porcelain evaporating dish about 120 mm diameter.
2. Spatula

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3. Container to determine moisture content
4. Balance with 0.01 g accuracy
5. Oven
6. Ground glass plate 20 x 15 cm for rolling
PREPARATION OF SAMPLE
Take out 30 g of air dried soil from a thoroughly mixed sample of the soil
passing 425 micron IS sieve, mix the soil with distilled water in a evaporating
dish and leave the soil mass for nurturing. This period may be up to 24 hours.
PROCEDURE
1. Take about 8 g of the soil and roll it with fingers on a glass plate. The rate of
rolling shall be between80 to 90 strokes per minutes to form a 3 mm diameter.
2. If the diameter of the threads becomes less than 3 mm without cracks, it
shows that water content is more than its plastic limit. Kneed the soil to reduce
the water content and roll it again to thread.
3. Repeat the process of alternate rolling and kneading until the thread
crumbles.
4. Collect the pieces of crumbled soil thread in a moisture content container.
5. Repeat the process at least twice more withfresh samples of plastic soil each
time. The Plastic limit shall be determined for at least three portion of the soil
passing 425 micron IS sieve. The average of the result calculated to the nearest
whole numbers shall be reported as the Plastic limit of soil.
SHRINKAGE LIMIT TEST
 The Shrinkage limit is the water content of the soil when the water is just
sufficient to fill all the pores of the soil and the soil is just saturated. The
volume of soil does not decrease when the water content is reduced

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below the Shrinkage limit. It can be determined from the following
relation -
Ws = (M1 – Ms) – (V1 – V2) ‫ץ‬w X 100 Ms
 Where M1 = Initial wet mass, Ms = Dry mass
 V1 = Initial volume, V2 = Volume after drying
APPARATUS
1. Shrinkage dish, having a flat bottom, 45 mm diameter and 15 mm
height.
2. Two large evaporating dishes about 120 mm diameters, witha pour out
and flat bottom.
3. One small mercury dish, 60 mm diameter.
4. Two glass plates, one plane and one with prongs, 75 x 75 x 3 mm size.
5. Glass cup, 50 mm diameter and 25 mm height.
6. IS sieve 425 micron.
7. Oven.
8. Desiccators.
9. Weighing balance, accuracy 0.01 g.
10. Spatula
11. Straight edge
12. Mercury
PROCEDURE

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1. Take a sample of mass about 100 g from a thoroughly mixed soil
passing 425 micron IS sieve.
2. Take about 30 g of soil sample in a large evaporating dish. Mix it with
distilled water to make a creamy paste, which can be readily worked
without entrapping the air bubbles.
3. Take the shrinkage dish, clean it and determine its mass.
4. Fill mercury in the shrinkage dish. Remove the excess mercury by
pressing the plain glass plateover thetop of the shrinkage dish. The plate
should be flush with the top of the dish, and no air should be entrapped.
5. Transfer the mercury of the shrinkage dish to a mercury weighing dish
and determine the mass of the mercury to an accuracy of 0.01 g. The
volume of the shrinkage dishis equal to the mass of the mercury in grams
divided by the specific gravity of the mercury.
6. Coat the inside of the shrinkage dish with a thin layer of silicon grease
or Vaseline. Place the soil specimen in the center of the shrinkage dish,
equal to about one thirdvolume of shrinkage dish. Tap the shrinkage dish
on a firm, cushioned surface and allow the paste to flow to the edges.
7. Add more soil paste, approximately equal to the first portion and tap
the shrinkage dish as before, until the soil is thoroughly compacted. Add
more soil and continue the tapping till the shrinkage dish is completely
filled, and excess soil paste projects out about its edge. Strike out the top
surface of the paste with the straight edge. Wipe off all soil adhering to
the outside of the shrinkage dish. Determinethe mass of the wet soil ( M1
).
8. Dry the soil in the shrinkage dish in an air until the color of pat turns
from dark to light. Then dry the pat in the oven at 105 ºC to 110 ºC to
constant mass.

34. 34
9. Cool the dry pat in a desiccators. Remove the dry pat from the
desiccatorsafter cooling and weigh the shrinkage dish with the dry pat to
determine
10. Place a glass cup in a large evaporating dish and fill it with mercury.
the dry mass of the soil ( Ms ).Remove the excess mercury by pressing the
glass plate withprong firmly over the top of the cup. Wipe of any mercury
adhering to the outside of the cup. Remove the glass cup full of mercury
and place it in another evaporating dish, taking care not to spill any
mercury from the glass cup.
11. Take out the dry pat of soil from the shrinkage dish and immerse it in
the glass cup full of mercury. Take care not to entrap air under the pat.
Press the plate with the prongs on the top of cup firmly.
12. Collect the mercury displaced by the dry pat in the evaporating dish,
and transfer it to the mercury weighing dish. Determine the mass of
mercury to an accuracy of 0.01 g. The volume of the dry pat ( V2 ) is equal
to the mass of mercury divided by the specific gravity of mercury.
13. Repeat the test at least 3 times.