Topic 9 Areas, Volumes, and Earthwork

Question 0

In construction, earthwork volumes are always moved for:

Answer 0

Highways, railroads, foundations.
Surveyors determine shape of ground surface which would then be used to determine volumes of materials to be removed or added.

Question 1

Borrow pits

Answer 1

Area borrowed from outside project site to obtain material to construct embankment at project site.
Contractor pay is based on quantities borrowed from pit x contract bid item price. Also, the owner of borrow pit is paid on quantity used.

Question 2

Slopes and stakes

Answer 2

Stakes are placed at stations to indicate how much cut or fill is needed at that station.

For fills: set stakes sloping outward.
For cuts: set stakes sloping inward.

Question 3

Area of cross section

Answer 3

Cross sections need to be taken at:

• beginning and ending of curves.
• locations where unusual changes in elevation occur.
• points where ground elevations coincide with natural grades.
• for certain applications such as rock and underwater excavation price is so high which requires cross sections at very close intervals roughly 10ft; for ordinary road: 50 to 100 ft

After determining the cross section area, the next step is to determine volume.
Use one of the methods:
- average end area method
- volume by prismoidal method

Question 4

Volume by Average end area method

Answer 4

• to find the volume between two cross sections.

- it is not exact method, to enhance accuracy make station closer.

Question 5

Volume by Prismoidal Method

Answer 5

MORE PRECISE.

• adjacent end areas are different from each other.
• prismoidal is a solid figure that has parrellel and plane faces (or bases) and sides that are plane surface.