This document discusses errors that can occur in measuring horizontal distances with a tape due to changes in temperature. One of the fundamental operations in surveying is measuring horizontal distance between two points using direct methods like taping. Tapes expand and contract with temperature changes, causing measured distances to be longer or shorter than the actual distance. To account for this, tapes are standardized to a specific temperature and corrections are applied to measurements based on the temperature at the time of measurement and the tape's coefficient of thermal expansion. A sample problem demonstrates how to calculate the corrected distance using the measured distance, observed and standardized temperatures, and coefficient of expansion for the tape.
This document discusses errors that can occur in measuring horizontal distances with a tape due to changes in temperature. One of the fundamental operations in surveying is measuring horizontal distance between two points using direct methods like taping. Tapes expand and contract with temperature changes, causing measured distances to be longer or shorter than the actual distance. To account for this, tapes are standardized to a specific temperature and corrections are applied to measurements based on the temperature at the time of measurement and the tape's coefficient of thermal expansion. A sample problem demonstrates how to calculate the corrected distance using the measured distance, observed and standardized temperatures, and coefficient of expansion for the tape.
Original Description:
Errors in Taping Operation in Measuring Length Due to Temperature
Original Title
Errors in Taping Operation in Measuring Length Due to Temperature
This document discusses errors that can occur in measuring horizontal distances with a tape due to changes in temperature. One of the fundamental operations in surveying is measuring horizontal distance between two points using direct methods like taping. Tapes expand and contract with temperature changes, causing measured distances to be longer or shorter than the actual distance. To account for this, tapes are standardized to a specific temperature and corrections are applied to measurements based on the temperature at the time of measurement and the tape's coefficient of thermal expansion. A sample problem demonstrates how to calculate the corrected distance using the measured distance, observed and standardized temperatures, and coefficient of expansion for the tape.
This document discusses errors that can occur in measuring horizontal distances with a tape due to changes in temperature. One of the fundamental operations in surveying is measuring horizontal distance between two points using direct methods like taping. Tapes expand and contract with temperature changes, causing measured distances to be longer or shorter than the actual distance. To account for this, tapes are standardized to a specific temperature and corrections are applied to measurements based on the temperature at the time of measurement and the tape's coefficient of thermal expansion. A sample problem demonstrates how to calculate the corrected distance using the measured distance, observed and standardized temperatures, and coefficient of expansion for the tape.
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Mapua Institute of Technology
Muralla St. Intramuros Manila 1002, Philippines
CE120 0 ELEMENTARY SURVEYING Errors in taping operation in measuring length due to temperature
Presented by: PINEDA, Manuel John F. SORITA, Mile Abraham
Topic to be discussed
Measurement of Distance - Errors in taping operation in measuring length due to temperature One of the most fundamental surveying operations is the measurement of horizontal distance between two points on the surface of the earth. Two basic methods of measurement Direct Used for determining horizontal distances with a tape(chain) and/or an electronic distance measuring instrument. Indirect (the transit and stadia or theodolite and stadia are used.)
Approaches (measuring horizontal distance) Pacing Taping Chaining Optical Rangefinders Odometers Tachometry Electronic Distance Measurement Global Positioning System
Measuring with the aid of a tape Accurate surveyors tapes are made of steel or a steel alloy with a typical length of 100 feet or 100 meters. Non metallic tapes are now common that are woven from synthetic yarns. For very accurate measurements, the temperature of the tape must be taken into account, as well as the tension of the pull. Each steel tape had its own temperature and tension coefficient which was used to correct each measurement.
Errors in taping operations in measuring 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 (or standard) temperature.
Errors in taping operations in measuring length due to temperature When measuring or laying out distances, there is always a change in temperature especially when the taping operation requires time to do so. Usually, to avoid circumstances where there is an introduced error due to temperature, tapes were standardized as a response to such factor, and a standard temperature for the tape determined. Errors in taping operations in measuring length due to temperature The correction of the tape length due to change in temperature is given by:
Where: Cf is the correction to be applied T is the observed temperature at time of measurement Ts temperature which the tape is standardized C coefficient of thermal expansion L length of the line measured Correction due to temperature The correction Cf is added to L to obtain the corrected distance.
d = L + Cf
Usually, for common tape measurements, the tape used is a steel tape with coefficient of thermal expansion C equal to 0.0000116 units per unit length per degree Celsius change. This means that the tape changes length by 1.16 mm per 10 m tape per 10 C change from the standard temperature of the tape.
Sample Problem:
The length of one side of a property was measured as 28.4 m. The temperature during observation was 39 degree celcius. The tape was standardized as 30m at 20 degree celsius. And the coefficient of expansion was 0.0000116 per degree celcius. Calculate for the corrected distance.
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
Sample Problem:
The length of one side of a property was measured as 28.4 m. The temperature during observation was 13 degree celcius. The tape was standardized as 30m at 20 degree celsius. And the coefficient of expansion was 0.0000116 per degree celcius. Calculate for the corrected distance.