errors in taping operation in measuring length due to temperature

8/10/2019 Errors in Taping Operation in Measuring Length Due to Temperature

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Mapua Institute of TechnologyMuralla St. Intramuros Manila 1002, Philippines

CE120 0

ELEMENTARY SURVEYING

Errors in taping operation inmeasuring length due totemperature

Presented by:PINEDA, Manuel John F.SORITA, Mile Abraham


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Topic to be discussed

Measurement of Distance

- Errors in taping operation in

measuring length due to temperature


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One of the most fundamentalsurveying operations is the

measurement of horizontal distancebetween two points on the surfaceof the earth.

Two basic methods of measurement Direct

Used for determining horizontal distanceswith a tape(chain) and/or an electronic

distance measuring instrument.

Indirect (the transit and stadia or theodolite

and stadia are used.)


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Approaches(measuring horizontal distance)

Pacing Taping

Chaining

Optical Rangefinders Odometers

Tachometry

Electronic Distance Measurement Global Positioning System


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Measuring with the aid of a tape

Accurate surveyors tapes are made of

steel or a steel alloy with a typical lengthof 100 feet or 100 meters.

Nonmetallic tapes are now commonthat are woven from synthetic yarns.

For very accurate measurements, thetemperature of the tape must be takeninto account, as well as the tension ofthe pull.

Each steel tape had its owntemperature and tension coefficientwhich was used to correct eachmeasurement.


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Errors in taping operations inmeasuring length due to

temperature

Most materials expand and contract

with temperature change, and this

affects taped distances. If a tape has

stretched due to heat it will read

shorter than it would at its normal (orstandard) temperature.


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temperature

When measuring or laying out distances,

there is always a changein temperature especially when the tapingoperation requires time to do so. Usually, toavoid circumstances where there is an

introduced error due to temperature, tapeswere standardized as a response to suchfactor, and a standard temperature for thetape determined.


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temperature

The correction of the tape length due tochange in temperature is given by:

Where:

Cfis the correction to be appliedTis the observed temperature at time of measurementTstemperature which the tape is standardizedCcoefficient of thermal expansionLlength of the line measured


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Correction due to temperature

The correction Cf is added to L toobtain the corrected distance.

d = L + Cf


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Usually, for common tape measurements, thetape used is a steel tape with coefficient ofthermal expansion C equal to 0.0000116 unitsper unit length per degree Celsius change.

This means that the tape changes length by1.16 mm per 10 m tape per 10 C changefrom the standard temperature of the tape.


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Sample Problem:

The length of one side of a property wasmeasured as 28.4 m. The temperature duringobservation was 39 degree celcius. The tape

was standardized as 30m at 20 degree celsius.And the coefficient of expansion was0.0000116 per degree celcius. Calculate forthe corrected distance.


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Given:

L = 28.4 m

C = 0.0000116 units per unit length per degree Celsius change.T = 39 deg. Celsius

Ts = 20 deg. Celsius

Required: D = ?

Solution:

Cf= (0.0000116)(28.4)(39-20)

Cf= -0.00230608

D = L + Cf ;= 28.4 + (-0.00230608) = 28.39769392m

following the correct no. of significant fig.

=28.4 m


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Sample Problem:

The length of one side of a property wasmeasured as 28.4 m. The temperature duringobservation was 13 degree celcius. The tape

was standardized as 30m at 20 degree celsius.And the coefficient of expansion was0.0000116 per degree celcius. Calculate forthe corrected distance.


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References:

http://faculty.kfupm.edu.sa/CE/hawahab/WEBPAGE/CE260/NOTES/2Chapter%202%20Linear%20Distance%20Measurement.pdf

http://en.wikipedia.org/wiki/Tape_correction_(surveying)#Correction_due_to_temperature

http://sudeshnairs.webs.com/surveying/4_uelsurveyingmeasurement.pdf
http://faculty.kfupm.edu.sa/CE/hawahab/WEBPAGE/CE260/NOTES/2Chapter%202%20Linear%20Distance%20Measurement.pdfhttp://faculty.kfupm.edu.sa/CE/hawahab/WEBPAGE/CE260/NOTES/2Chapter%202%20Linear%20Distance%20Measurement.pdfhttp://faculty.kfupm.edu.sa/CE/hawahab/WEBPAGE/CE260/NOTES/2Chapter%202%20Linear%20Distance%20Measurement.pdfhttp://en.wikipedia.org/wiki/Tape_correction_(surveying)http://en.wikipedia.org/wiki/Tape_correction_(surveying)http://en.wikipedia.org/wiki/Tape_correction_(surveying)http://sudeshnairs.webs.com/surveying/4_uelsurveyingmeasurement.pdfhttp://sudeshnairs.webs.com/surveying/4_uelsurveyingmeasurement.pdfhttp://sudeshnairs.webs.com/surveying/4_uelsurveyingmeasurement.pdfhttp://sudeshnairs.webs.com/surveying/4_uelsurveyingmeasurement.pdfhttp://en.wikipedia.org/wiki/Tape_correction_(surveying)http://en.wikipedia.org/wiki/Tape_correction_(surveying)http://en.wikipedia.org/wiki/Tape_correction_(surveying)http://faculty.kfupm.edu.sa/CE/hawahab/WEBPAGE/CE260/NOTES/2Chapter%202%20Linear%20Distance%20Measurement.pdfhttp://faculty.kfupm.edu.sa/CE/hawahab/WEBPAGE/CE260/NOTES/2Chapter%202%20Linear%20Distance%20Measurement.pdfhttp://faculty.kfupm.edu.sa/CE/hawahab/WEBPAGE/CE260/NOTES/2Chapter%202%20Linear%20Distance%20Measurement.pdf

errors in taping operation in measuring length due to temperature

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