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Tutorial One(5) - Practice notes
Construction Technology 2 (Substructure) (300721)
Western Sydney University
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Tutorial 1
Surveying & Earthmoving
Part 1. Areal Calculations
Boundary distances and bearings
CIVL
Civil & Substructure
####### In Practical One, the Total Station was used to generate the Northings and Eastings of the four
####### corners of the grid.
####### On your contour plan, you will be expected to report the length and bearing of each boundary.
####### Figure 1 First quadrant boundary
####### For a first quadrant boundary:
####### the end Northing is larger than the start Northing: N2 > N1.
####### the end Easting is larger than the start Easting: E2 > E1.
####### Using Pythagoras’ rule, the Length of a first quadrant boundary:
2 1 2 1
2
length first quadrant N N E E
####### The Bearing of the first quadrant boundary (measured from True North):
1 2 1 2 1
tan
first quadrant
####### E E
####### bearing
####### N N
1 3 4 4 3
tan
####### bearing second quadrant
####### N N
####### E E
####### Note that the Northings are reversed in the bearing calculation.
####### Figure 3 Third quadrant boundary
####### In a third quadrant boundary:
####### the end Northing is smaller than the start Northing: N6 < N5.
####### the end Easting is smaller than the start Easting: E6 < E5.
####### Using Pythagoras’ rule, the Length of a third quadrant boundary:
6 5 6 5
2
length third quadrant N N E E
####### The Bearing of the third quadrant boundary (measured from True North):
1 5 6 5 6
tan
third quadrant
####### E E
####### bearing
####### N N
####### Note that the orders of the Northings and Eastings are reversed in the bearing calculation. By Euclid’s
####### theorems:
####### So a third quadrant boundary can be turned into a first quadrant boundary by reversing the start and
####### end points. The bearing should be reported as a first quadrant angle.
####### Figure 4 Fourth quadrant boundary
####### In a fourth quadrant boundary:
####### the end Northing is larger than the start Northing: N8 > N7.
####### the end Easting is smaller than the start Easting: E8 < E7.
####### Using Pythagoras’ rule, the Length of a fourth quadrant boundary:
8 7 7 8
2 2
length fourth quadrant N N E E
####### Just as a third quadrant bearing should be reported as a first quadrant angle, a fourth quadrant
####### bearing is reported as a second quadrant angle.
####### Figure 5 Site grid
####### Discussion
####### a. The dimensions of the grid are 60m by 40m. Estimate the surveyed area in m 2.
####### b. Using the internet, explain the difference between Magnetic North and True North.
Part 2. RL Calculations
####### Our levelling exercise is a closed traverse.
####### Figure 6 RL Calculations
(from visitsydneyaustralia.com)
####### In a closed traverse:
####### the sum of Backsights must equal the sum of the Foresights
####### the sum of Rises must equal the sum of Falls
####### Both sums must be zero.
####### Make sure that you work through the calculations in Figure 6. Starting with the Backsight, Inter sights
####### and Foresight, derive the Rise/Fall and Reduced Level of each point.
####### You use the survey data generated by the Automatic Level in Practical One to derive the Reduced
####### Levels (RLs) for each station on the grid (Figure 5). You use the sheet on the next page. You should
####### follow the pattern used in Figure 6.
####### When a staff reading is higher than the reading at the previous station, the base of the
####### staff has been lowered between the two stations. So a higher staff reading means a
####### Fall.
####### Conversely, a staff reading will be lower when the base of the staff is raised between two
####### stations. So a lower staff reading means a Rise.
####### The Reduced Levels are calculated in sequence from the top of the sheet downwards.
####### The second line of Figure 6 has a fall of 0 m. Given that the Bench Mark has an RL
####### of 86, the RL of Point 2:
2 86 0.
85.
####### RL
####### You will need to print out Table 1. After you have completed the RLs, scan the sheet with your
####### smartphone or scanner. Insert the images in Submission One. Report the RLs to the nearest 0. For
####### instance, the Reduced Level above should be reported as “85” NOT “85”.
####### Discussion
####### b. It seems backwards ..... “a higher staff reading means a Fall”. In your own words, explain
####### why the statement is correct.
####### c. Discuss with your tutor why the sum of Rises must equal the sum of Falls in a closed
####### levelling traverse. You will be asked to justify this in Submission One.
Part 3. Contour maps
####### The Reduced Levels (RLs) are used to create contour maps. You will be using the RLs from the
####### levelling exercise to create your own contour map of the area that will be excavated for fill.
####### Figure 7 Contours
(abridged from surveyingestimating.blogspot)
####### Contour maps indicate the topography of a site. The contours look like squiggly lines on the bottom
####### panel of Figure 8. But those “squiggly lines” carry a lot of information, as you can see in the top panel
####### of Figure 8.
####### Figure 8 Contour and Topographical maps
(from dlsweb.rmit.edu)
Contouring
####### Print out the file “Grid” as an A3 sheet. Once you have plotted the RLs on the grid of the surveyed
####### area, you can determine where each contour crosses a grid line. As an exercise, find the difference in
####### height between two node points:
height 101 100 0
####### Figure 9a Contour Interpolation (loose and stretched rubber band)
####### Figure 9 detail of Contour Interpolation
####### Take a flat elastic band (about 5 mm wide) and draw 10 intervals on the band with a permanent
####### marker. When loose, the 10 intervals should fit between two grid points on your Grid plan. To find
####### where the 101 m contour crosses between the two grid points, stretch the rubber band so there are
####### five intervals between the two grid points:
####### Count 2 intervals to the right from the node (RL = 101) [Green line] OR/AND
####### Count 3 intervals to the left from the node (RL = 100) [Orange line]
####### You can count in both directions as a check.
####### With a needle (or similar sharp object), mark the location of the RL101 contour intersection on your
####### plan.
####### You should mark all the grid intersections on your contour plan. Then you draw free-hand lines for
####### each contour, passing through each intersection point.
####### At this stage, your contour plan should have the following information:
####### 1. Distance and Bearing of each boundary
####### 2. Each Grid Intersection RL
####### 3. Contours at 1 metre increments
####### Once you have completed the contour map, you must scan the plan and insert it in your Submission
####### One.
####### Discussion
####### b. Using the Practical One notes, explain how RLs are related to the Australian Height Datum
####### in Submission One.
####### c. Your tutor won’t help you with this one. He will only tell you if you have the wrong explanation:
####### Can contour lines ever overlap?
Part 4. Excavation Volume
####### Once you have completed the contouring, you have to calculate the volume of spoil that would be
####### excavated from the surveyed area:
####### The excavation area ends at the perimeter of the surveyed area. You don’t need to worry
####### that the sheer embankments will cave into the excavation. You can assume that sheet
####### piling has been driven into the ground on the perimeter of the surveyed area.
####### The excavation starts at the lowest point of the surveyed area. In Figure 10, you excavate
####### down to an RL of 98 [ bottom right-hand corner].
####### Figure 10 Average RLs for each sector
(abridged from surveyingestimating.blogspot)
####### In Figure 10, the average RLs are shown in Blue. You must do the same exercise for the surveyed
####### grid.
####### You calculate the average RL for each cell by averaging the four RLs at each corner. For the bottom
####### left-hand cell in Figure 10:
(101 100 100 100)
100.
4
Average RL
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####### and
####### Komatsu Australia
####### komatsu.com/
####### You will need to consider many factors in the selection of earthmoving equipment. It is difficult to
####### specify exactly what configuration of machines your group uses. But generally, you will need to
####### consider the following factors, which will affect the cycle time:
####### 1. Excavator Production rate: assume that you are using a hydraulic excavator with a 0.
####### m 3 bucket. Its production rate is 15 m 3 / hr in soil.
####### 2. Truck cycle
####### i. Truck Loading
####### ii. Truck Acceleration (away from excavation pit)
####### iii. Truck Travel (to soil dump near overpass) – Use the travel distance from Practical
####### One.
####### iv. Truck Off-load (at soil dump)
####### v. Truck Return (to excavation pit)
####### Your tutor will help you with reasonable estimates of the times (truck travel, truck off-load, etc.). The
####### calculations are entered on page 17.
####### The Truck haulage rate is determined by dividing the Truck capacity by its Cycle time:
3
Truck haulage rate m 3 / hr Truck capacity m
####### Truck cycle hr
( )
( )
( )
####### The number of trucks must be large enough to ensure that the excavator does not wait at any time.
####### You should ensure that there is always one truck waiting at the excavation pit. So the haulage rate
####### must be balanced with the production rate of the excavator:
3 3
/
/
####### Excavator production rate m hr
####### Number of trucks
####### Truck haulage rate m hr
( )
( )
####### Once you have completed the calculations, you must scan page 17 and insert it in your Submission
####### One.
####### Discussion
####### b. Discuss with your tutor what happens when the haulage rate of all trucks is less than the
####### excavator production rate.
####### c. The excavator production (15 m 3 / hr) is an ideal rate. What factors will reduce the production
####### rate?
Summed excavated top volume (m 3 ) =
Total excavated volume m( 3 ) Summed excavated top volume m( 3 ) Additional volume m( 3 )
3 3
( 1 30%)
1.
####### Volume of Spoil m Total excavated volume m( )
####### Total excavated volume m( )
( )
Loading (min) =
Acceleration (min) =
Travel (min) =
Off-load (min) =
Return (min) =
####### ______________________________________________________________________________
Truck cycle (min) =
OR (hr) =
####### Truck type:
Truck capacity (m 3 ) =
3
Truck haulage rate m 3 / hr Truck capacity m
####### Truck cycle hr
( )
( )
( )
Tutorial One(5) - Practice notes
Course: Construction Technology 2 (Substructure) (300721)
University: Western Sydney University
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