S4 Chain Survey

7/23/2019 S4 Chain Survey

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It is the technique, profession, and

science of accurately determiningthe terrestrial or three-dimensionalposition of points and the

distances and angles between


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Types of SurveyingT

ypes of Surveying


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Topic of PresentationT

opic of Presentation


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What is done in ChainWhat is done in Chain

SurveyingSurv

eying In Chain Surveying, only linear measurements are

made i.e. no angular measurements are made.Triangle is the only !gure that can be plotted withonly measurement of sides to enclose an area.

"ence, in chain survey area to be plotted should becovered with a networ# of triangles. Therefore, chainsurveying is also #nown as Triangulation. Chainsurvey is the simplest method of surveying. In thissurvey only measurements are ta#en in the !eld,and the rest wor#, such as plotting calculation etc.are done in the o$ce. This is most suitable adaptedto small plane areas with very few details. Ifcarefully done, it gives quite accurate results.


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Suitable casesSuitable cases

%rea to be surveyedis comparativelysmall.

&round is fairlylevel.

%rea is open.

'etails to be !lled

up are simple andless.

(on-Suitable(on-Suitable

casescases

%rea to be surveyedis large.

&round is quiteuneven.

%rea is crowded.

'etails to be shown

are too many.


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)equirements for a Chain)equirements for a Chain

SurveySurveyChain*easuring tape

)anging rod

%rrowsCross Sta+

egs

ield boo#

lumb bob


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ChainChain % chainis a unit of length it measures // feet or

00 yards or 122 lin#s.

There are 12 chains in a furlong, and 32 chains in onestatute mile.

%n acre is the area of 12 square chains 4that is, anarea of one chain by one furlong5.

The chain has been used for several centuries in6ritain and in some other countries in7uenced by6ritish practice.

The ends of the chain are provided with handles fordragging the chain on the ground, each wire with aswivel 8oint so that the chain can be turned withouttwisting.


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The length of the chain is measured fromthe outside of one handle to the outside ofanother handle.

ollowing are the various types of chain in

common use9 *etric Chains

&unter:s Chains

;ngineers Chains

;tc.


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*;T)IC C"%I(S*;T)IC C"%I(S*etric chains are made in lengths 02m and


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&>(T;):S C"%I(&>(T;):S C"%I(

?ne of the !rst chains used in the >.S. wasthe &unter:s chain.

The &unter:s chain was a series of lin#sattached to a handle which included anad8ustment for wear.

The chain was 00 yards 4// ft5 long.


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*;%S>)I(& T%;*;%S>)I(& T%; % tape measureor

measuring tapeis a7e=ible form of ruler. Itconsists of a ribbon of cloth,plastic, !ber glass, or metalstrip with linear-measurement mar#ings. It isa common measuring tool.Its 7e=ibility allows for a

measure of great length tobe easily carried in poc#etor tool#it and permits one tomeasure around curves orcorners.


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The following are the various types of tapes

Cloth tape

*etallic tape

Steel tape

Invar tape %mong the above, metallic tapes are widely

used in surveying. % metallic tape is made ofvarnished strip of waterproof line interwoven

with small brass, copper or bron@e wires.These are light in weight and 7e=ible and aremade 0m, Am 12m, 02m,


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)%(&I(& )?')%(&I(& )?')anging rods are used to range some

intermediate points in the survey line .

The length of the ranging rod is either 0m or


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%))?WS%))?WS%rrows are made of good quality hardened

steel wire of B mm diameter.

The arrows are made B22 mm in length, arepointed at one and the other end is bentinto a loop or circle


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C)?SS ST%C)?SS ST%The simplest instrument used for setting

out a right angle.


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?S;T )?'S?S;T )?'SThe o+set rod is used for measuring the o+

set of short lengths.It is similar to a ranging rod and is usually

of


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;&S;&SThese are rods made from hard timber and

tapered at one end, generally 0Amm or


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>*6 6?6>*6 6?6While chaining along sloping ground, a

plumb bob is required to transfer the pointsto the ground.


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Technique of unfolding andTechnique of unfolding and

folding of a metric chain.folding of a metric chain.

>(?'I(&9)emove the strap of the folded chain and ta#e

both the handles in the left hand and hold theremaining portion of the chain in the right hand.

"olding both the handles in the left hand, throwthe remaining portion o f the chain in theforward direction on the ground.

(ow the follower stands at the starting station

by holding one handle and directs the leader tomove forward by holding the other handle untilthe chain is fully stretched.


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?'I(&96ring the two handles together on the

ground by pulling the chain at the center.

Commencing from the center two pairs oflin#s are ta#en at a time with the right handand placed alternatively in both directionsin the left hand.

When the chain is completely folded thetwo brass handles will appear at the top.

(ow tie the chain with leather strap.


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distancedistance

'I);CT*;%S>);*;(T

Counting of paces9

assometer

edometer >se of wheel-based

instruments9

erambulator

?dometer

Speedometer

I('I);CT*;%S>);*;(T

It involves methodssuch as tachometry,

electromagneticdistancemeasurement, andtrigonometric

leveling. Tachometry uses a

theodolite !ttedwith a stadia

diaphragm or a


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Technical terms usedTechnical terms used

ST%TI?(- It is a point of importance at thebeginning or at the end of a survey line.

*%I( ST%TI?(- These are the stations at the

beginning or at the end of lines forming mains#eleton.

S>6SI'I%)D ?) TI; ST%TI?(S- These are thestations selected on main lines to runau=iliaryEsecondary lines for the purpose oflocating interior details.


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6%S; I(;- It is the most important line and is thelongest line. *ain framewor# of survey lines arebuilt on it.

';T%I I(;- If the important ob8ects are far awayfrom the main lines, the o+set readings are toolarge, which results into inaccuracies and time-

consuming in the !eld wor#. In such cases thesecondary lines are run by selecting stations onmain lines.

C";CF I(;S- These are the lines connecting mainstation to a subsidiary station on the opposite sideor connecting two subsidiary stations on the sides

of main lines. These lines are also #nown as )??I(;S.


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Selection of StationsSelection of Stations

% station selected should be visible from at leasttwo more stations.

If possible should have one or two base lineswhich run on level ground and through the

middle of the area.*ain frame should have as few lines as possible.

%ll triangles should be well-conditioned.

;ach triangle should have at least one chec# line.

Subsidiary stations should be selected such thato+sets to main ob8ects from subsidiary lines areas short as possible.


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%void obstacles to ranging and chaining.

%s far as possible survey lines should be onthe level ground.

Sides of the larger triangles pass as close toboundary lines as possible. They should bealmost parallel to the boundary.

Trespassing and frequent crossing of the roadsshould be avoided.


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?+sets?+sets

ateral measurements to chain line for

locating ground features are #nown as ?+sets.There are two types of o+sets used in chain

surveying vi@. ;);('IC>%) ?S;T and?6IG>; ?S;T.

In case of perpendicular o+set, foot of theperpendicular on chain line is found from theob8ect and the surveyor notes down o+set

distance and the chainage of foot of the

perpendicular.In case of oblique o+set, the distance of the

ob8ect from two convenient points on the

chain lines are measured and noted down.


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Setting out erpendicularSetting out erpendicular

?+sets?+sets

erpendicular o+sets maybe set by

Swinging >sing cross sta+s

>sing optical square

>sing prism square


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erpendicular o+set byerpendicular o+set by

SwingingSwinging

The leader ta#es the end of the tape andholds it on the ob8ect.

The follower swings the tape on the chain lineand !nds the shortest distance of the ob8ect

from the chain line.Since the perpendicular distance is the

shortest distance of a point from a line, it isnoted as the perpendicular distance.

The follower reads the correspondingchainage and the o+set length.

The recorder records it in the !eld boo#.


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rism SquarerismSquare

It wor#s on the principle as the opticalsquare.

In this case, a prism with angle betweenre7ecting surfaces of BA degrees is used as

shown.


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;rrors;rrors

Incorrect length of chain.

Incorrect ranging.

oose chain.

Temperature change.

Hariation in pull. ;rrors in slope measurements.

Incorrect mar#ing.

ersonal mista#es.

Cumulative errors.

Compensating errors.

ield Wor#ield Wor#


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ield Wor#ield Wor#

Reconnaissance- )econnaissance of the area tobe surveyed has to be underta#en !rst. This

identi!es #ey features of the area the survey are tobe located and determines the #ind of equipmentneeded to be carried to complete the survey.

Equipment- &enerally the following equipment

will be required. % chain with at least 12 arrows, ametallic or steel tape, a do@en of ranging rods, ano+set rod, pegs, a plumb bob, etc.

Marking stations- Survey stations should bemar#ed on the ground as per the plan prepared.

Chaining and locating details-The survey linesare then measured accurately, starting from thebase line. The details are located by ta#ing o+setat right angle or oblique o+sets.

ott ng a a n urvey ceo n

g a a n urvey ce


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ott ng a a n urvey ceo ng a a n urvey cewor#5wor#5

%fter carrying !eld wor# ne=t step in surveyingis plotting to get plan of the area surveyed. It iscarried out by the surveyor himself or theassistance of the draftsmen may be obtained.

Steps involved in plotting are as follows9

SCALE: 'epending upon the are in the !eld

and area of drawing sheet scale is decided.(ormally, it is decided before thecommencement of survey itself


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R!E"TAT!": S#eleton of the networ# of

triangles should be drawn to a scale on atracing sheet and the orientation of the plan ondrawing sheet be decided. %fter the orientationis decided using the s#eleton diagram on

tracing sheet base line and stations are pric#ed.

#RA$!"% "ET$R& ' TR!A"%LES: irstbase line is drawn to the scale. 6y intersection

other stations are !=ed and main triangles aredrawn. The networ# of triangles is chec#edusing chec# lines.


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PLTT!"% ''SETS: %ny one of the followingmethods may be used- *ar# points along chain line and draw

perpendicular with set square. If oblique o+setsare ta#en, arcs are drawn from the respectivepositions on chain line and the position of theob8ects !=ed up.

*ain scale and o+set scale may be used. *ainscale is #ept along direction of chain line and

o+set scale gives the perpendiculars to it.

T(ER #ETA!LS: If readings are ta#en to only oneor two faces of buildings, using overall dimension

outline of the building may be completed.&raphical scale should be plotted so that even ifthe paper shrin#s, correct measurements may beobtained without calculations.


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Conventional ColoursConventional Colours

)oads- 6urnt SiennaE6rown.

6uildings- ight &rey.

Compound wall- Indigo.

Water- 6orders edged withrussian blue.

Trees- &reen.


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Conventional SymbolsConventional Symbols


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tape onlytape only

Though triangulation is the basic principle of

chain surveying, it is possible to go fortraversing using only chain and tape.

Traversing is the survey which is conductedalong desired lines by measuring the length

and the direction of survey lines.C?S;' T)%H;)S;- When the lines form a

circuit which starts from a line and aftercovering an area ends at starting point.

?;( T)%H;)S;- If the starting point ofsurvey and ending point are di+erent.

Closed traverse- la#es and building surveys.

?pen traverse- road and canal surveys.


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6ibliography6ibliography

)ooks-

Surveying and eveling, S.S. 6havi#atti

Surveying and eveling, T.. Fanet#arand S.H. Ful#arni

$e*sites-

mcs.nust.edu.p# www.google .com


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%arushi Fhatri - 11/2/

%run Fumar - 12/12

%neesha 'himan - 11/2

(isha Fumari - 11/2

S4 Chain Survey

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