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ESRM 468 Forest
Operations Paper Location of
Road |
Assignment 1
Map with two road locations: due 4/05/2010
9.00am
Write-up of map project: due 4/11/2010, 5:00pm
Turn in assignments under “Collect
It”
You will be given two topographic map of the St. Edward Park vicinity and a DEM. Two existing roads are labeled 'Road #l' and 'Road #2'. A landing site is also marked. Our job this Quarter is to design, locate and stake a road connecting the landing to Road #1 or #2.
The Pegger instructions are here. They are in addition to what is available from Pegger Help
The pegging project, discussed below, is carried out on the Lidar map (ArcGIS Lidar DEM)
Remember to save the zip file directly in the C-drive (see instructions). Folder and file_names CANNOT have empty spaces!
After a grade line has been pegged (located), it can be imported into RoadEng for further analysis and design. The steps are explained in
"Importing Unit Survey Into RoadEng"
1. Slope Classes
First create a slope class map using a set of divider drawing the slope classes on a mylar overlay (old-fashioned way) or in ArcGIS.
The slope classes to use are
0 - 30 percent
30 - 50
>50
The information is useful to evaluate generally suitable road location areas.
2. Road Location (pegging)
The next step is to "peg" a paper road location on the map, first from the landing to Road #1, and then from the landing to Road #2. Road standards to use are:
- maximum grade = 10% adverse, 15% favorable
- minimum curve radius = 60'
- switchback on < 35% sideslopes only
- 12' running surface
- total length of road, which runs parallel to a creek within 150 ft,
cannot exceed 500 ft.
- stay within the Park boundary
Check references
Pearce, 1961. Forest Engineering Handbook, pages 79-85
Various references on the class web page
3. Road Cost Estimation
Divide the road into the following sideslope classes and determine road length (in stations) for each class:
sideslopes
0 - 30 percent
30 - 50
>50 percent
For each slope class calculate the required excavation volume based on a standard cross section with the following dimensions for each road:
The following road dimensions are to be used:
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Traveled width |
12 ft |
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Ballast depth |
12 inches |
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shoulder slope |
2:1 |
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Ditch width and depth |
3 ft, 1ft |
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cut slope ratio |
1:1 |
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fill slope ratio |
1.5:1 |
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assume that 2/3 of road bed are in hill slope and 1/3 on fill portion on sideslopes <50%
Use the following average side slopes
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for roads on slopes in the range of: |
use this average slope value |
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0 -30 % |
20 % |
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30 - 50 |
40 |
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> 50 |
60 |
Estimate road construction costs for each alternative using the USFS excavation rate. Assume common earth for excavation and costing purposes.
Road construction costs consist of
-Clearing & grubbing
clearing is the process of removing (felling) timber from the right of way
grubbing is the process of removing stumps/rootwads from the construction area.
Typically a common cost value used for clearing & grubbing is $ 600.-/acre
-Excavation; use table values below
U.S.F.S. unit rate for excavation.*
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Type of Material |
Base Unit
DOLLARS/CYD |
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Common |
$0.90 |
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Rippable |
$1.80 |
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Solid |
$3.60 |
Slope Adjustment Factor adjust base rate with factor below, based on material
0-30% : 1.0
30-50% : 1.2
Over 50% : 1.4
-Rock (Road ballast); @ $ 10.-/cubic yard in-place
-Cross drain culverts @ 100.-/station
stream culverts separate, if any
Report the costs as total $ values and also in $/station.
Provide the relative ratios (percent) of each cost component in the total (e.g. clearing/grubbing, ballast, excavation, drainage/culverts)
4.
Selection of alternative
Choose one of your two locations as the 'best' road to build. Justify your choice (e.g. based on total cost, location, stream proximity, etc)
Keep both road locations marked on your map, but for the chosen 'best' location clearly mark grades to run and distances to each grade break and bearings on the map. A copy of this map will be taken into the field and will be the basis for your trial gradeline.
5. Report
Turn in a report containing your map and all of the information discussed above.