Taping ON EVEN OR Level Ground and Taping ON Uneven OR Sloping Ground PDF

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Taping on even or Level Ground and Taping on Uneven or Sloping Ground...

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TAPING ON EVEN OR LEVEL GROUND and TAPING ON UNEVEN OR SLOPING GROUND I.

INTRODUCTION:

If taping is done on fairly smooth and level ground where there is little underbrush, the tape can be held on the ground. The taping party consists of the head tape man and the rear tape man. The head tape man leaves one taping pin with the rear tape man for counting purposes and perhaps to mark the starting point. The head tape man takes the zero-end of the tape and walks down the line toward the other end. When the 30-m end of the tape reaches the rear tape man, the rear tape man calls "tape" to stop the head tape man, The rear tape man holds the 30-m mark at the starting point and aligns the head tape man (using hand signals) on the range pole which has been set behind the starting points. Ordinarily, this "eyeball" alignment of the tape is satisfactory but the use of a transit will slightly improve the precision. When the rear tape man has the 30-m mark at the starting point and has satisfactorily aligned the tape, he calls or signals "all right" to the head tape man. The head tape man pulls the tape tightly and sticks a taping pin in the ground. The rear tape man picks up his taping pin and the head tape man pulls the tape down the line and the process is repeated for the next 30-m. It will be noticed that the number of 30-m lengths which have been measured at any time equals the number of taping pins which the rear tape man has in his possession. When the end of the line is reached, the distance from the last taping pin to the endpoint will normally be a fractional part of the tape. This fractional distance is measured and added to the number of 30-m lengths measured previously to give the final horizontal distance. For sloping ground or uneven ground, taping is handled similarly to taping over level ground. The tape is held horizontally but one or both tape men have to use plumb bobs.

Sometimes large elevation difference makes it impossible to use an entire tape. situations only part of the tape is In such used. The head tape man holds the zeroend and the rear tape man holds a convenient distance which will allow the selected length of tape to be horizontal. All individual measurements must be recorded as shown in the figure Another procedure for measuring up or down a slope is called the "breaking tape” method. The rear tape man holds the 30-m end of the tape over a point while the head tape man proceeds forward until it becomes impossible to keep the tape horizontal, e.g., at the 25-m mark. The rear tape man then moves up to the head tape man and holds the tape at the 25-m mark over the new point while the head tape man proceeds until the 0-mark of the chain are reached at which point the whole process is repeated. Each 30-meter length of tape must be recorded individually. (See figure).

II. EQUIPMENT: 30-m or 100-ft steel tape Range poles Chalk or marking crayons Spring scale

III. PROCEDURE: In taping, there are 2 tape men, the head tape man, and the rear tape man. A third may act as a recorder or lineman. If there are only 2 performing the taping, the rear tape man shall act as recorder.

A. MEASURING ON EVEN OR LEVEL GROUND 1. Both head and rear tape men mark both ends of the line to be measured using chalk or marking crayons. A range pole is placed behind each point to ensure an unobstructed line of sight. These endpoints are designated as A and B. 2. Both tape men proceed to the starting point. The rear tape man stays on the starting point while the head tape man takes the 0-meter end of the tape and moves toward the direction of the end of the line to be measured. When the tape is about to be fully unraveled from the reel, the rear tape man shouts “tape” or signals to the front tape man to stop. 3. The head tap tape man faces the rear tape man then waits for an alignment signal. The rear tape man aligns the tape held by the front tape man by waving his hand towards the right with the palm towards the direction of motion, or with the left hand for a left motion. When the tape is in line with the range pole set at the endpoint, the rear tape man shows hand palm forward notifying the front tape man for correct alignment. 4. The rear tape man places the end graduation of the tape on the point behind and signals “all right”. The head tape man pulls the tape about 10 lbs. and sets a mark with a chalk/ marking crayon and signals “all right”. The rear tape man then signals the head tape man to move “forward”. Both tape men proceed forward and repeat the procedure until the last full-tape measurement before the endpoint. 5. The fractional tape length is measured by placing a full meter-mark against the last pin with the end of the line contained within the first fractional or graduated meter (from 0-mark to 1-m mark). That portion of the tape which protrudes beyond the end of the line is then subtracted from the full meter-mark opposite the last marking. After the measure of the whole line is completed, a second measurement should be made along the opposite direction. The mean of the two measurements is taken as the most probable value of the length of the line.

6. Compute for the Discrepancy and Relative Precision using

The discrepancy between two measurements must give a relative precision of not greater than 1/2000 for tertiary, 1/5000 for secondary, and 1/10,000 for the primary survey. It is, however, recommended that measurements must check within 1/1000 whenever possible.

B. MEASURING OVER UNEVEN OR SLOPING GROUND 1. Measuring uphill. a. On a designated uneven and sloping terrain, mark the ends of a line (about 90m long) to be measured. Designate the bottom of the slope as point A and the upper portion of the slope as point B. Range poles are held or set behind each point to serve as markers or are set at intermediate points along the line to ensure better alignment during the taping. b. Head tape man unreels and spreads out the tape and pulls the zero-mark uphill along the line from point A. The rear tape man raises the terminal end of the tape breast-high while the head tape man moves uphill until the ground surface is as high as the raised end of the tape at point A. The head tape man pulls the tape until it is approximately level with the head tape man. c. The rear tape man temporarily releases end of the tape and signals head tape man to either move to the right or the left to align him. When the tape of the head tape man is in line with the range pole held over point B, the head tape man is signaled to hold his position. d. The rear tape man plumbs the terminal mark of the tape with a plumb bob and maintains this plumb bob steadily over A while head tape man pulls the tape taut. The head tape man is then signaled to make a mark on the ground to the nearest full meter or footmark of the tape. e. The rear tape man leaves his end of the tape, moves up the slope and gets hold of the tape at the point previously held by the head tape man. The next measurement is made horizontally from the mark on the ground made by the head tape man as done at point A.

f. The process is repeated until the whole tape length is used up thus finishing the measurement of one tape length of horizontal distance. g. From the end of one tape length measurement, the horizontal measurement is continued until point B is reached. The last partial tape length is measured with the rear tape man holding the tape until he has a full meter (or foot) mark at his end while the head tape man pulls the tape taut and takes note of the factional measurement. Then the number of tape lengths and the last partial measurement are totaled to determine the horizontal length of the line measured. 2. Measuring downhill. a. In measuring down the slope, the tape is reversed to bring its zero-end forward in the direction of point A along the line. Horizontal measurements start from B with the rear tape man holding the terminal meter (or foot) mark of tape in level with B. b. After the plumb bob of the head tape man has been aligned with the range pole held at A, the head tape man leaves a marking on the ground. c. The next horizontal measurement starts from the first marking until one whole tape length is measured. As in measuring up the slope, the number of tape lengths plus the partial tape length at the end of the line determines the total horizontal length of the line. 3. Record field data and compute the results using the same formulas used in taping on level ground for the discrepancy and relative precision....