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How to make temperature correction for a steel tape in surveying? / How to calculate true length for temperature correction?

 Eg:

A 30m. surveyor's steel tape is correct at 21°C. The distance measured by using this tape on a day when the temperature is 32°C is 230m. Calculate the true distance between the points by applying temperature correction. Coefficient of thermal expansion ∝ = 1.4 х 10⁻⁵ per ° C.


To find:

The true distance between the points.


Calculation:




The true length 

 L = [ Measured length + temp. correction.]

 L = [ L1 + Ct ]


Now,

The temperature correction is calculated by the formula

Ct = [ ∝ х ( Tm - To ) х L1 ]

   Where,

∝ = Coefficient of thermal expansion =  1.4 х 10⁻⁵

Tm = Field temp. = 32°C

To = Standard temp. = 21°C

L1 = Measured distance = 230m.

Ct = [  1.4 х 10⁻⁵ х ( 32°C - 21°C ) х 230m. ]

     = 0.0354m.


The true length between the points

   L  = [ L1 + Ct ]

       = [230m. + 0.0354m.]

    L = 230.0354m.

To understand A to Z of surveying, click here.

Thank you for going through these calculation steps. Have a good day 😄.

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