COSC 301 Construction Surveying & Layout Activity IX Total Station; Final Site Circuit Survey

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1 COSC 301 Construction Surveying & Layout Activity IX Total Station; Final Site Circuit Survey Introduction Set Up 1. Review Chapter 8 Total Station & EDM. 2. This activity will test your ability to set up and use a Total Station and apply it to measure and record a small site. It cover the following concepts: Equipment for Linear Measurement Fieldwork procedure and field book entries Total Station set up and measurement Electronic Distance Measurement Principles of electronic distance measurement Equipment for electronic distance measurement Graphic communication, AutoCAD 3. This exercise will take place in the field north of New Main and on the survey circuit your crew was assigned. Make sure you follow the exact circuit by hub by hub. 4. Each crew will be responsible for measuring the angles of their circuit on the New Main survey field with a surveyor s total station, recording the data in their field book, and reporting the results of their field work. This exercise will take place in the survey field north of New Main. 5. The components of this activity are: A. This section of the activity will test your ability to set up on a survey point and use a total station to measure and book the angles and all distances of a closed circuit. B. The next section will require the drawing of the measured circuit in an AutoCAD drawing. C. Deriving and book unmeasured angles and distances. D. The third section will require you to report your field measurements and data. 6. Survey equipment to be taken into the field: a. Total station b. Tripod c. Prism Pole with Prism d. Bipod e. 25 Engineer s Tape 1. Inspect the equipment for damage etc. Make sure that you battery has life left in it, prior to going into the field. If not, charge it. If there is damage report it immediately to the instructor or TA. 2. Make sure you have your sample field book set up appropriately BEFORE you start and have a print out of the survey circuit (From previous work). 3. Take a copy of your instrument instructions into the field with you. 4. Secure a clean copy of the A9D.dwg AutoCAD file. 5. Complete the survey exercise as directed. Section A Angle, Vertical, Horizontal, and Slope Measurements of a Closed Circuit 1

2 1. Set up the total station anywhere in the field where you can easily see and measure all of your circuit s hubs, BM3 and BM2. This is your Temporary Datum (TD) location. Measure and enter the instrument height into your total station. The HI measurement is taken from the ground directly below your instrument to the centerline of your prism optic. Adjust the height of your prism and pole so that you will be able to measure all hubs without changing the height of rod measurement. However, you can change your rod height if required to make a measurement, but you must then change the recorded measurement in you total station. Be very careful with both the leveling and HI/Rod Height measurements. Double or even triple check your readings. They can significantly affect your accuracy. 2. You are to measure and record the same distinct circuit around the New Main Field that you measured in previous circuit activities only this time using the Total Station. You will also measure to BM2 and BM3. Note that the Total Station will provide you with DMS to an accuracy of one second and distance measurements to thousandths. This is quite different than the accuracy of some of the Theodolites which only provided twenty seconds of accuracy. 3. Place the prism and pole on the top/center of benchmark (BM2) at AMS and zero your instrument. This BM2 measure will allow you to accurately locate your circuit on the New Main Field within the AutoCAD drawing. You should take at least two readings and book the following field information in your field books: (Figure 1) Stations/Hubs/BMs Horizontal Angle/Turning Point Angle Calculated Turning Point Decimal Angle Horizontal Distance Vertical Distance Slope Distance 4. Do not relocate the instrument, remain on the TD. Record the position of all of the circuit s hubs and the two BMs. Precision of measurements is extremely important. Two observers should repeat the measurement at least twice to ensure accuracy has been achieved. If there is a discrepancy in numbers, take the measurement until agreement has been achieved between observers. Figure 1: Field Book Example. Section B Drawing an AutoCAD Drawing of a Closed Circuit 1. Make sure you return all your crew s equipment and have clearly measured all the required angles for your circuit. Each crew member will download a copy of the A9D.dwg file from the Assignments Page of the web site. 2

3 2. This AutoCAD drawing has the necessary Northing line for you to be able to establish your Home Hub angle as related to the northing line BM2 to BM3. The following angles are also necessary. Standing on the BM2, looking toward BM3, the angle to the left is the left hand angle and the angle to the right is the right hand angle. The angle between BM3/BM2/ Your Home Hub is made available to you on the course assignments page under "Northing Back Sight Angles for Activities VII and IX". 3. Using AutoCAD, draw your field measured side-shot lines and align them using the measured side shot angles and distances measured. The measures to BM2 and BM3 from your TD will establish the exact point of your instrument s location. Connect the hub end points from your chosen TD to construct your circuit s chain lines. (Figures 2 through 5) Delete all circuit construction lines after the hub locations are fixed. 4. Dimension all exterior circuit chain lines and all interior Hub/Turning Point angles. If an interior TP angle exceeds 180 you must use the Dimangular command to create the angle dimension. Note: DIMANGULAR will provide angle dimension greater than 180 Type into the Command line DIMANGULAR and then Enter Mouse right click Pick pivot point Pick right-hand ray Pick left-hand ray Mouse left click and position the dimension Figure 2: Establish Temporary Datum. 3

4 Figure 3: Field side-shots. Figure 4: Establishing circuit sides. 4

5 Figure 5: Finding chain lengths and turning-point angles. Section C Calculating the Elevations and Clockwise/Reverse Measures of Your Closed Circuit 1. After you finalize you AutoCAD file transfer your computed measurements to your field book. (Figure 6). A back sight (BS) measurement is to the left of the hub you are standing on while facing the interior of your circuit. A forward sight is to the right. 2. From your AutoCAD drawing, transfer the angle and horizontal distances to your field book. The hub elevation, BS/VD, and BS/SD will not be provided by AutoCAD. You will need to commit your measurements to a calculation algorithm to determine the correct value. THINK!!! With a little thought you should be able to construct a correct formulation. The numbers within the example figure may be wrong and will not match with your measurements, so be careful. As a check, you might refer to your previous activities to ensure that your values are similar. Enter the calculated values into your field book. Station/Hub Hub/Turning Point Angle Back Sight Horizontal Distance Turning Point Elevation Back Sight Vertical Distance Back Sight Slope Distance 5

6 Figure 6: Field Book Example. Submission #1 A9FB.pdf Scan your own field book entries and save them as a PDF file. Name this file A9FB.pdf. Go to the course web site and upload your own PDF file. This file upload represents a finished product, and should be done as soon as your crew completes the field activity. Submission #2 A9D.dwg Each crew member will produce an AutoCAD drawing of their crew s final circuit. Dimension the AutoCAD drawing produced to compute all measures between hubs and the interior turning-point angles for each of your hubs by using the dimension Aligned, Dimangular, and Angle commands. Draw only in Model space. No drawing may be done in Layout space. Upload a copy of your AutoCAD drawing. Name this file A9D.dwg. Your final drawing should be modeled after the Final AutoCAD Drawing illustration (Figure 7). 6

7 Figure 7: Final AutoCAD Drawing. Section D Survey Data and Field Measurements Submission Submission #3 Field Measurement and Data As a crew - log into the Assignments page of the course web site and select the link Submit Assignment Data and Scoring, then pick on the Assign #9 button. Your crew will be provided a form to enter your crews angle measurements along with crew member participation; submit (check your submitted values), and score your data (by submitting the values again). You may either enter in values in DMS or values in Decimal Degree, not both. DO NOT wait until the last minute. All activities are due prior to the next assignment period or as directed. 7