Report Travesing PDF

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Description

FACULTY OF CIVIL ENGINEERING & EARTH RESOURCES ENGINEERING SURVEYING FIELDWORK LINEAR SURVEY REPORT SUBJECT CODE

BAA 1912

SUBJECT

ENGINEERING SURVEYING FIELDWORK

DATE

28 MARCH 2019

GROUP NUMBER

1

SECTION

04

GROUP MEMBER: NAME & ID NUMBER

LECTURER MARKS REMARKS ENDORSEMENT

TABLE OF CONTENT

NO.

CONTENT

PAGE NUMBER

i)

INTRODUCTION

1

ii)

OBJECTIVE

2

iii)

DEVICES/EQUIPMENT

2-3

iv)

PROCEDURE

4-6

v)

PRODUCT

7

vi)

DISCUSSION/ANALYSIS

8-9

vii)

CONCLUSION/RECOMMENDATION

10

viii)

APPENDICES

11-12

INTRODUCTION

Traversing is a form of a control survey that requires the establishment of a series stations that linked together by angles and di stance. It can be open traverse and close traverse. The angles are measured by theodolites and the distance can be measured by calculating the stadia's reading or using electronic distance measuring equipment. The use theodolites in traversing survey is one of the most common methods in engineering work to get the provision of control surveys, angle measurement and detail mapping. Theodolite is an instrument used for measuring horizontal and vertical angles. Vertical angles are required for the calculation of elevation of points, for example the reduction of slope distance to the horizontal. Horizontal angles are required to obtain the relative direction to a control point or station of detail. It gives accuracy u to 1’’. In this field work, we only consider the horizontal angles and distances in closed traverse. In a closed traverse the angle measured either interior or exterior according as the traverse is run in a counter clockwise direction. Generally closed traverse in clockwise direction. The successive lines are measured and the bearing of the starting line is observed. The bearing of the remaining lines are then found from the observed bearing and the measured angles. Traversing by this method is done either. The angle can be measured by repetition so as to desire degree of accuracy is obtained.

OBJECTIVES 1. To make close traverse survey (planimetric control) of a parcel of ground within UMP area by linear survey technique which is using built-in EDM (Total Station). 2. To produce of the scaled drawing of traverse survey. 3. To be familiar with the checks and errors in a closed traverse and solve them. 4. To know the advantages of bearing and the uses in various survey works.

LIST OF DEVICES a) 1 set of built-in EDM or total station completed with accessories

b) 2 sets of reflectors completed with accessories

c) 3 sets of tripod stand

d) Fieldbook

PROCEDURE

1. Setted up the Theodolite. ➢ Tripod is setted up. The tripod legs was spreaded out on the ground around the survey point.

➢ Mounted the instrument The theodolite is carefully removed from the box and screwed to the tripod.

➢ Centring A sight is taken through the optical plummet to view the survey peg. The footscrews are turned to bring the instrument exactly over the peg. The theodolite is now centred but, not level.

➢ Levelling Levelling is accompolished by raising or lowering the legs of the tripod, using the sliding leg arrangement, until the circular spirit level is centred.

Refinements to the centring and leveling of the instrument must now be made; (a) the plate spirit level over two screws were setted up and the bubble have been centralised, (b) the instrument turn through 90o and recentralised the bubble (c) operations (a) and (b) is repeated until the bubble remains central for both positions.

➢ Parallax elimination A piece of paper is held in front of the telescope and the observer, sighting the paper through the telescope, the eyepiece turned carefully until the cross-wires of the reticule are sharply defined.

2. Setted up Back Bearing (Topcon GTS220)

➢ Released Horizontal and vertical plate, and the theodolite in face left position. ➢ Theodolite Display Panel is switched on. Make sure horizontal bearing in the mode Horizontal Right (HR). ➢ Rotate the theodolite horizontally, till the required horizontal bearing had been display in panel. ➢ Refinements to the required horizontal bearing, using horizontal tangent screw. ➢ Pressed the (F2)(HOLD) key. ➢ Collimated the target above the back station. ➢ Pressed the [F3](YES) key to finish holding the horizontal angle.

PRODUCT

5.0 DISCUSSION Our group was given a task at one specific location to construct a closed loop traverse using a theodolite. We are required to measured the horizontal and vertical angles of five stations which are labelled as 1, 2, 3, 4, and 5. We had used about 4 hours to complete all the scope works. Basically, we know that all stations are laid out on the site respectively. The theodolite will be placed on Station 1 which is our starting point and started to conduct our survey. The angles that we get from the theodolite must be read from left face to the right face in order to obtain more accurate readings. The zero angle will be set on Station 1 as well and turned the theodolite to Station 5 and measure to get the reading as well as the horizontal and vertical angles. After we get all of readings and angles, we switch the theodolite to Station 2 and the steps repeated again to get another point of readings. While doing the surveying works, there are three main factor that could influence our reading. The factors are: 1. Human Factor •

The readings taken are not consistent because there is more than one observer. Parallax error also could be occurred.

2. EnvironmentFactor •

The hot weather could disturb our concentration and makes us difficult to focus on the prism.

3 . Instrument Factor •

Reading on our station would be not so accurate since the picket already left for weeks and could be disturbed by any movement of living things and object.

After we get the readings and angles from all station, our data processing by computer to make a traverse adjustment report. From the report, we achieved 343.0371 for bearing misclose. Since we constructed a closed loop traverse, the bearing misclose should be in 360°, so that the northing and easting value would be 0.000. By doing some latitude correction (northing misclose: 0.013) and departure correction (easting misclose: -0.004), we achieve the theoretical value for northing and easting. We found that our area of traverse site is 995.132m2 and perimeter is 162.255m. Accuracy for our project is 1:12380 (in ratio) which is classified as Class I which is quite good for our level of constructed survey. Otherwise for value over 5000 will be classified as Class II.

CONCLUSION AND RECOMMENDATIONS

We can conclude that the field work that we have conducted in group was successful because we recorded all the necessary data and details that help us to figure out our site area. Each group member was involved ia all traverse survey activities alternatively and every member was able to cooperate with each other. We learnt to conduct a traverse survey by using a theodolite and several formulas that we learnt during traversing class. There are several difficulties while traverse survey was conducted. What we found out that was really hard for us is we couldn’t get the spirit bubble into the black circle. Then, because of the human factor which is the readings taken are not consistent because there is more than one observer. Parallax error also could be occurred. For the improvement of this fieldwork, it is important to follow the procedure correctly and to set the equipments with technique properly because wrong set up might cause innacurate results. In order to obtain a more accurate reading the angles that we get from the theodolite must be read from left to the right. We also must make sure that zero angle will be set on first point. There are few more recommended improvement. We need to find a suitable place to set up our stations. This is because easy to set up the equipment for traverse survey. We need to know how to read the readings from the theodolite. After conducting the fieldwork, we have learned how to conduct a traverse survey by using a theodolite and finish the work as well and our group get Class I which is quite good for our level of constructed survey.

APPENDICES...