Site Surveying Fieldwork 2


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Site Surveying Fieldwork 2

  3. 3. Objective: The objectives of this field work are: - To have a better understanding of the procedure for traversing. To have experiences to the actual working environment on the site including uncertainty weather condition. To have witness the usage of equipment and apparatus on site. To have the ability to setting up the tripod and adjusting the staff bubble. To understand how to find out the azimuth from a point to another. To have skills in using the auto meter level for correct reading To increase the team working skills among group members. To have the ability in recording data for the field work To understand the angle of adjustment of traversing. To have skills in applying formulae in calculation.
  4. 4. Introduction: Our second fieldwork for Site Surveying is on traversing. We are required to do another fieldwork and report with traversing to measure a chosen area. We have been assigned to do our fieldwork on traversing at an open space area on Block E in Taylor’s University Lakeside Campus. We were required to take four points on the open space area to do close traversing. The equipment required to do traverse survey are slightly different from leveling survey. The equipment required to do a complete traverse survey are the Tripod, Automatic Level, Measuring Tape and Plumb Bob. Hence, one of the equipment is missing will cause a traverse survey unable to complete. Therefore, each of the equipment of traverse survey is extremely important. Traverse survey is a survey where we set up the Automatic Level at a point and measuring few different pinpoints. The angles of the pinpointed stations and the distance between two points are measured and note down. Traverse survey are measure with high accuracy to positions a small numbers of pinpointed stations. Moreover, less precise measurements can be made to features to be located without accumulating accidental errors. There are two types of traverse survey which are the closed traverse and the opened traverse. The difference between a closed traverse and an opened traverse is that one has the same starting and ending point. Where else, the other one will have different starting and ending points. A closed traverse have same starting and ending point which means at the end of the measuring we will go back to the same point. An opened traverse will have different ending point from the starting one. In the nutshell, a closed traverse has benefits over an opened traverse. A closed traverse can be refer back to the angles where it is measured as they have the same starting and ending point and check its’ errors, where an opened traverse have different starting point and ending point which its’ errors or mistakes cannot be discovered.
  5. 5. Apparatus: Basically, we were doing traversing work in our 2nd site surveying fieldwork. We need a tripod, a dumpy level, some ranging rods (measuring rod) and a measuring tape in order to finish this fieldwork. Tripod: A tripod is a portable three-legged frame, used as a platform for supporting the weight and maintaining the stability of some other object. A tripod provides stability against downward forces and horizontal forces and movements about horizontal axes. Automatic level: An automatic level, auto level meter, leveling instrument, or dumpy level is an optical instrument used to establish or check points in the same horizontal plane. It is used in surveying and building to transfer, measure, or set horizontal levels. The automatic level is set up on a tripod and set to a leveled condition using foot screws (leveling screws). Ranging rod: A ranging rod is also name as measuring rod or range pole rod. It is a pole for marking positions in surveying. It is a straight rod painted in bands of alternate red and white each one foot wide and used for sightings by surveyors. Measuring tape: A measuring tape is a flexible ruler that allows for a measure of great length to be easily carried in pocket or toolkit and permits one to measure around curves or corners. It consists of a ribbon of cloth, plastic, fiber glass, or metal strip with linearmeasurement markings. It is a common measuring tool. Picture above shows a tripod.
  6. 6. Picture above shows a automatic level. Picture above shows some ranging rods.
  7. 7. Picture above shows a measuring tape.
  8. 8. Discussion: Our group consists of five members. In this fieldwork, we are required to conduct traversing around the campus. Here, the main activity we have to conduct is to set up the measuring rod at different points and use the auto level machine to calculate the angle between the measuring rods. The site which we conduct traversing is at the balcony at L.2. In this fieldwork, we are going to set up a closed traverse. We were told that a closed traverse will basically consist of four points which will make up a polygon. Closed traverse involves the usage of interior angle to locate the points of the measuring rod. We set up our tripod with the auto level meter on it. Having the air bubble inside the boundary of the circle is to ensure the auto level meter is on a flat surface. Then one of our group members holding the measuring rod is required to stand at the point we fixed. The important thing here is that the person holding the measuring rod has to maintain the rod at the fixed point and remember where the point is located as this affects the accuracy of measurement. Our problem is that we only have two measuring rod for each group. The first point is measured as 0˚ and till the second measuring rod is set up, the angle between these two points is measured. In order to solve this problem, we use stones to pinpoint the location of the measuring rod. Next, the length from the center of the tripod to the point of the measuring rod is measured. We also measured the length between the measuring rods. We are also encouraged to take a larger distance between the measuring rods. In order to get the center below the auto level meter, the plumb bod is hung onto the hook at the center of the tripod. In this fieldwork, our group is effective and fast. We were fast enough to finish our traversing before the sun gets too hot. We had set up four points as required and after measuring all the lengths and angle between the measuring rods from the auto level meter, our group get some confusion when we looked back to our data. Our group members started to discuss about the data collected. Here, our lecturer, Sir Wong JeeKhai help us a lot as he gave us a few questions to be thought through so that we knew how we could get two of the internal angles at the end and found out where is the root of our problems. Our problem is mainly about data recording. The angle measured is in between the measuring rod taking the tripod as the center but the recording of data records the internal angle to be the angles between the measuring rods. Throughout this process, we are required to think and discuss among ourselves to solve this confusion and we learn how to discuss and cooperate among each other so that we can find the answers to our question. At the end, we were able to understand the steps to calculate the internal angles using both the length and angles we had measured. The solution here is to have a clear idea on the angles we have and use the trigonometry to find the length and angles of other parts. After all these data collection and discussion, we started calculating all the internal angles of our closed traverse. When we found out there is an error present, we had to carry out the angle adjustment for closed traverse. This process requires the balancing of internal angles, computation of latitudes and departure and also the balancing of latitudes
  9. 9. and departures. Latitude can be considered as the ∆Y and departure as the ∆X. The calculation will include calculation using trigonometry sin and cos. As we were not given the coordinate of one of the point, we could not compute the coordinates of the remaining points. Below are the formulae we used in calculation: 1. Sum of internal angle of polygon = (n – 2) x 180˚ 2. Misclosure = 3. Latitude (∆Y) = Distance (H) cos α 4. Departures (∆X) = Distance (H) sin α 5. Error = ∑∆Y / ∑∆X 6. Correction = Error x 7. Adjusted ∆Y = ∆Y – Correction 8. Adjusted ∆X = ∆X – Correction –
  10. 10. Conclusion: Traversing is one of main task to identify the pin point on the map or in construction drawing, so that we will stick to the boundary accurately. In this field work we did come through some of the obstacle and have greater understanding on traversing. By carry out this field work, we find that it is much harder compared with calculations we do in the class. It is because there are so many mistakes we could pick up by not concentrating on what we are doing or rushing it. Moreover, it allows us to hands-on on the equipment. This is a great experience to explore and have a better knowing on the equipment. Furthermore, our team have shown a good team work spirit. All of us get to their own station and carry out their duty in no time. Besides that, we have adopted a systematic way to carry out the task. We try to picture out the area that we are going to measure and distribute job accordingly. In conclusion, this field work benefit us by stepping out of the classroom which allow us to open our up our eyes and look into the practical part of it.