WEEK 4 Report - E2 - TOPIC: LEVELLING SURVEY - LONGITUDINAL CROSS-SECTION OF ROAD PDF

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TOPIC: LEVELLING SURVEY - LONGITUDINAL CROSS-SECTION OF ROAD...

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FACULTY OF PROG./COURSE CODE : COURSE : GENERAL FIELD MAINTENANCE TOPIC: LEVELLING SURVEY - LONGITUDINAL CROSS-SECTION OF ROAD FIELDWORK NO. G. LEADER NAME MATRIC NO. GROUP (COURSE) NO. 1. 2. 3. 4. 5.

NAME

MATRIC NO.

CHECK LIST FOR REPORT SUBMISION & CONTENT 1. REPORT COVER – fill in all the blanks, print and submit 2. Introduction (summarise) 3. Objectives (summarise) 4. Learning outcomes (summarise) 5. Procedures 6. Bookings of Survey Data (during fieldwork) 7. Propose Sketch of Longitudinal Levelling Survey (during fieldwork) 8. Plotting Longitudinal Profile of Road 9. Conclusions 10. Discussion and Recommendations 11. Appendixes: Others- Photographs, Tables & Sketches with captions

TICK ( /)

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INTRODUCTION With one major exception, profile levelling is very similar to benchmark levelling. Several more foresight readings on as many points as required may be made at each instrument position where an HI is calculated by a rear sight rod reading on a benchmark or turning point. Another method of profile levelling is cross-sectional levelling. The phrase "cross-section" refers to a brief profile view of the ground drawn perpendicular to a highway or other linear project's route centerline. Cross-sectional drawings are particularly useful for calculating the amount of earthwork required to build a road. During the route profile survey, cross-section rod shots are typically taken from the same instrument sites as rod shots along the centerline.

OBJECTIVE To give exposure to the students about the process of determining the elevation of points on the ground at mostly uniform intervals along a continuous line.

LEARNING OUTCOME By the end of this FW session students should be able to: 1. setup level equipment. 2. take back sight, intermediate sight and fore sight reading. 3. make correct booking. 4. calculate reduced level of all the point taken perform correction to the reduced level.

5. plot a longitudinal profile and cross section with a suitable scale.

EQUIPMENT Auto Level – 1

Levelling Tripod – 1

Levelling Staff – 1

Staff Bubble – 1

Ranging Poles – 3

Arrows- 10

Plum bob – 1

Tapes - 1

PROCEDURE Longitudinal Levelling (50m length) 1. Select at assumed Bench Mark 100m (BM 100M) peg position at CH 0m for the level to be set up. 2. Set up the level and make the temporary adjustment. 3. Place the staff at the bench mark and take the reading. This reading is a back sight. 4. Note the reading in the form provided. 5. Place another staff at a distance of 5m from the first staff. 6. Take the reading of the second staff and note as the intermediate sight. 7. Measure a distance of 5m from the second staff, and place the third staff position. Note the reading in the field sheet as intermediate sight. 8. Repeat step 5 to 7 until the staff cannot be read. The last reading of the staff before the level is move is noted in the column as foresight. The staff at the foresight position (before moving the level) must not move until the (becoming) back sight (after moving the level) reading is taken. 9. Move the level to new suitable position and make the temporary adjustment. 10. Take the back sight reading 11. Repeat step 5 to 10 until the work is completed. 12. Calculate the Rise and Fall and the reduced level of all the staff positions. 13. Plot the longitudinal profile of the road. Plot on GRAPH PAPER for Longitudinal Cross Section for Road Making.

BOOKINGS OF SURVEY DATA (DURING FIELDWORK)

B.S 0.46

I.S

F.S

RISE

FALL

0 0.410

0.050

0.504 0.680 0.990 1.50

0.094 0.176 0.310 0.450

1.440

R.L 100.00

DISTANCE 0

0 100.05

5

0 99.956 99.780 99.470 99.020

10 15 20 25

99.260 98.900 98.195 98.190

30 35 40 45

0 1.260 1.620 2.325 1.96

0.240

2.330 3.770

0.290

0.360 0.705 0.005 2.100

0

ARITHMETIC CHECK TOTAL B.S – F.S = TOTAL RISE – FALL = LAST RL – FIRST RL 1.960 – 3.770 = 1.810 0.290 – 2.100 = 1.810 98.190 – 100.00 = 1.810

REMARKS STARTING POINT = 100M

CP1

PROPOSE

SKETCH

FIELDWORK)

OF

LONGITUDINAL

LEVELLING

SURVEY

(DURING

CONCLUSION In conclusion, we are able to measure, collect data, tabulate, analyse and interpret data to produce this report. With this knowledge, we are able to adjust the errors by error distribution methods. this fieldwork helps us to understand better on the concept of levelling. We will get to learn on how to conduct the fieldwork and how to use the levelling apparatus. In this case, the rise and fall method are used to obtain the reduce levels and errors are distributed by dividing the errors by number of set ups to get the average error to occurred in every set ups. Other than that, by using the data, we will able to produce the fieldwork report.

DISCUSSION By using differential method of the levelling difference in elevation from a given point to same certain distance can be determined and for this operation the elevation of benchmark is given. So, during the surveying of differential levelling certain error may arise due to wind factor and fault adjustment of auto level. Other than that, the reduced level is adjusted by using the loop mis-closure method which is the correction per set up is calculated to distribute the error. For your information, all the reduced level is adjusted and the final reduce level is equivalent to the original given benchmark level.

RECOMMENDATIONS -

Students should avoid from taking measurement near magnetic sources such as hand phone, watch, electric cable and others.

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Next, student must make sure the bubbles are properly level

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Besides, students also need to do triple check with the work and reading to make sure there will be no mistake.

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Lastly student should make sure that the plum bob properly centered over the peg to avoid from the incident or injuries to the students.

REFERENCE 1. Reference from lecture given by Sir Redzuandi Abdul Rahim

APPENDIXES

TAPE

POLE ARROW

STAFF BUBBLE PLUM BOB

LEVELLING STAFF

AUTO LEVEL

LEVELLING TRIPOD...