Road and Trail Midterm Flashcards
Areas for good control points
- landings
- existing roads
- ridge tops and saddles
- benches
- switchbacks
Preferred landing gradient
2-5%
Areas to avoid for control points
- Fish stream crossings
- Wetlands/RMZ
- Slopes over 50%
- Rock outcrops
- Middle of broad flat valleys
- Wildlife and other sensitive areas
- neighbors
Birds eye view of a map is called
Plan view
View of map from the side is called
Profile view
Different road cuts (4)
cut and fill, full bench, through cut, and through fill
different road surfaces (3)
outsloped, insloped, and crowned
center line
an imaginary line that runs longitudinally along the center of the road.
side-cast fill
Excavated material pushed on prepared or unprepared slope next to the excavation to construct the roadbed.
What is a through cut
road cut through a hill slope or a ridge. Both sides have a cut slope.
What is a through fill
Opposite of through cut. Fill slopes on both sides of road.
Subgrade
Material beneath the surface material.
Surfacing course (surfacing)
The top layer of the road surface.
Maximum grade for favorable slopes
18%
Maximum grade for adverse slopes
14%
Grade required for landings
5%
Cut and fill slope ratios
Cut - 1:1, fill - 1:1.3
What is a balanced cut and fill
Utilizes all cut materials to generate fill material. No excess waste and no end haul.
Elements to road planning (3)
avoid sensitive areas, minimize costs, and minimize length.
Fish passage structures (3)
squash bottom, stream simulation, and bridge.
Switchback gradient
No more than 8-10%
Dimensions of ditch relief pipes (western WA)
18” x 40 ‘
Dimensions of stream crossing pipes (western WA)
24” x 40’
What is a disconnect pipe
Used to disconnect ditch from stream. Place 50’ away from streams.
