FIELDRP2

FIELD WORK REPORT NO. 2

Mabuti, Roy Jason M. 2013107712 CE120-0F/A4

GRADE

Group No. 3

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MAPUA INSTITUTE OF TEHNOLOGY ELEMENTARY SUREYING FIELD WORK REPORT

˜Table of Contents˜ Page 2 Introduction Page 3 Objectives and Instruments Page 4 Procedures and Computation Page 7 Questions and Problems Page 8 Preliminary Data Sheet Page 9 Final Data Sheet Page 11 Research and Discussion Page 12 Conclusion Page 13 Fieldwork Peer Assessment

Chief of party: Araracap, Jasper Date of field work: July 20, 2015 Date of submission: July 27, 2015

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INTRODUCTION

This fieldwork emphasizes uneven ground measurements. In measuring the distance on uneven ground, the meter tape needs to be positioned about an eye-level distance.

This fieldwork is prone

to errors, most especially, due to sag. In surveying, tape correction refers to correcting measurements for the effect of temperature and tension, catenary and to reduce measurement on the slope to the equivalent horizontal length. Not correcting for these effects gives rise to systematic errors as the effects act in a predictable manner which can be corrected by mathematical methods.

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OBJECTIVES AND INSTRUMENTS

Objectives:

To develop the skills of taping the distance on a level ground where the tape is fully supported by the ground. To acquire the skills of taping the distance on an uneven ground where the taping is only supported at the ends.

Instruments: Two range poles Chalk/ 1 set of marking pins 2 plum bobs 50 meter tape

Plum bob- A weight, usually with a

pointed tip on the bottom, that is

suspended from a string and used as a

vertical reference line, or plumb-line. Range pole- A conspicuously

painted pole held upright to show

the position of a survey mark.

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PROCEDURES AND COMPUTATION Procedure:

A) 1. The professor assigns the accessible and unobstructed

course to be measured by the student on a level ground by about 300 paces-400 paces.

2. The Chief of Party marks the end points by a chalk if it is on pavement or by a 3” common wire nail if it is on soft ground and designate it as end points A and B.

3. A range pole man holds the pole vertically and steadily during the entire taping procedure at B to keep the complete taping process aligned and straightened.

4. A 10-meter tape is stretched out on the ground on the straight path along A to B where the 0-end is held ahead. The rear tape man is responsible for giving the signal to the front tape man if his path is straight while the front tape man is responsible to pull the tape taut once the tape is aligned already.

5. The front tape man gets a pin and sticks it vertically in the ground exactly opposite the 0-meter mark of tape.

6. Rear tape man holds one pin and the rest of the pins (10 pins) are held by front tape man.

7. Both the front and the rear tape man lift simultaneously the tape and move forward along the line AB to measure the next tape length. By now, the rear tape man holds 1 marking pin which signifies one tape length.

8. The procedure 4-6 is repeated to complete the next tape length measurement. Make sure that the rear tape man pulls the pin before lifting the tape to move on to the next tape length. The rear tape man holds the two marking pins to connote 2 tape lengths have been measured.

9. Repeat all process until all the pins being held by the front tape man have been used up which signifies one tally (1 Tally = 10 tape

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lengths). After a tally has been accomplished, the rear tape man returns all the 10 pins to the front tape man to proceed in measuring the length of the course.

10. Repeat the same procedure if more than one tally is needed. 11. Upon reaching point B the partial length must be measured

accurately up to centimeters by the rear tape man while the front tape man holding the 0 mark at B and both of them are holding the tape taut.

12. The number of small pebbles in the rear tape man’s pocket now indicates the number of tallies made and the number of pins in his possession indicates the number of additional tape lengths. This is recorded in the field computation sheet provided.

13. The course is measured back and forth to complete the number of trials required by the professor.

B)

1. The same course is measured but this time the 10-m tape length will be unsupported by the ground and must be held about an eye-level distance above the ground.

2. Both the rear and the front tape man hold a plumb line over the center of the hub.

3. The front tape man must hold his plumb line an arm’s length away from his body for the rear tape man to clearly see if it is aligned in the range pole at B.

4. Once the rear tape man approves of the alignment, the rear tape man is holding the 0-mark pulls the tape taut and drops this plumb bob on the ground. This will mark the ground with a dent to guide the front tape man where he must place his marking pin.

5. This is to be done continuously until point B is reached. Note that the partial length, must also be measured as in procedure A.

6. The course is measured back and forth to complete the number of trials required by the professor.

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Computation:

A) Computation of an unknown distance:

The number of tallies is equivalent to the number of pebbles being held by the rear tape-man, and the number of pins is the number of tape lengths. Multiply the number of tallies by 10 and add it to the number of pins. The sum is then multiplied by the length of one tape length and then added to the last partial tape length to get the length of the course AB.

𝑁𝑜. 𝑜𝑓 𝑡𝑎𝑙𝑙𝑖𝑒𝑠 = 𝑁𝑜. 𝑜𝑓 𝑝𝑒𝑏𝑏𝑙𝑒𝑠

𝑁𝑜. 𝑜𝑓 𝑡𝑎𝑝𝑒𝑙𝑒𝑛𝑔𝑡ℎ𝑠 = (𝑁𝑜. 𝑜𝑓 𝑡𝑎𝑙𝑙𝑖𝑒𝑠) ∗ 10 + 𝑁𝑜. 𝑜𝑓 𝑝𝑖𝑛𝑠

𝐿𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑡ℎ𝑒 𝑐𝑜𝑢𝑟𝑠𝑒 𝐴𝐵= (𝑁𝑜. 𝑜𝑓 𝑡𝑎𝑝𝑒𝑙𝑒𝑛𝑔𝑡ℎ𝑠) ∗ (𝐿𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑜𝑛𝑒 𝑡𝑎𝑝𝑒𝑙𝑒𝑛𝑔𝑡ℎ)+ 𝑝𝑎𝑟𝑡𝑖𝑎𝑙 𝑙𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑡𝑎𝑝𝑒

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QUESTIONS AND PROBLEMS

1. What are the different sources of taping errors? Errors in measurements stem from three sources: personal, instrumental, and natural.

2. Discuss the ways to lessen them or fully eliminate taping errors. Common sense, self-calibration (estimating personal errors by experiments and experience) and attention to proper procedures generally keep such errors to a minimum. Most instrumental errors are eliminated by using proper procedures, such as observing angles in direct and reverse modes, balancing foresights and back sights and repeating measurements. Since not all instrument errors can be eliminated by procedures, instruments must be periodically checked, tested and adjusted (or calibrated.) Instruments must be on a maintenance schedule to prevent inaccurate measurements. Natural errors are mostly systematic and should be corrected or modeled in the adjustment.

3. What is the total length of the course XY if the rear tape-man hold exactly 9 pebbles and 3 pins after measuring the course XY? Assume that one tape length is equivalent to 30 m.

XY= [(9)(10)+3](30)

XY=2790m

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PRELIMINARY

DATA

SHEET

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FINAL

DATA

SHEET

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Sketch: jbkbjkbjkkkkkkkk

Marking the 10 meter tape using a plum bob.

The range pole man holds the pole

vertically and steadily during the

taping procedure.

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RESEARCH AND DISCUSSION Measuring Distance over Uneven Ground

all measurements in plane surveying are taken to be horizontal achieved using either of the following methods:

a. the tape is held horizontally while the measurements are taken, or b. the tape is held along the ground slope and a correction is applied to the slope measurement.

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CONCLUSION

In this fieldwork, I learned that whether the ground is leveled or uneven, I can still measure the distance between two points on the ground. I also learned the use and importance of plumb bob in this fieldwork.

I think the one major source of error in this fieldwork is due to sag. Leveling the meter tape on an eye level may cause the meter tape to sag.