Page 96 - Moving the Earth_ The Workbook of Excavation

SURVEYS AND MEASUREMENTS

2.46 THE WORK

FIGURE 2.42 Pile measurement.

PRODUCTION MEASUREMENTS

In the construction industry the word “production” is assigned the same meaning as “output,”
which is defined in the dictionary as “the quantity or amount produced, as in a given time.”
Perhaps a better definition for these words in construction is “useful work accomplished,” as in
the early stages of a job the chief product is likely to be destruction and upheaval.
Production may be figured in at least three ways. First is on the basis of job requirements. If a
time schedule allows 200 working days to move 3,000,000 yards of earth, the contractor’s earth-
moving machines must move or “produce” 15,000 yards per day. Second, the production of a cer-
tain machine is measured or estimated, to determine the number of such machines needed to meet
the production required. If a certain scraper can move 1,000 yards a day under this job’s condi-
tions, the contractor must keep at least 15 of them working at that rate.
The third way of figuring production is in terms of cost. This is the final and important calcu-
lation, as it is the basis on which contracts are let, and on which contractors ride in Cadillacs or
go broke. But cost calculations are unlikely to be accurate or useful until job conditions and equip-
ment are known.
Earthmoving quantities may be measured in terms of bulk of material, weight of material, area
to be worked, or lineal feet or yards processed.

Cubic Measure. Most earthmoving is computed in cubic yards. A cubic yard is a cube 3 feet
long, 3 feet wide, and 3 feet high. It is about 6 inches greater in each dimension than the space
occupied by a card table.
“Cubic yard” may be stated and written in full, but is usually shortened to “yard” or abbrevi-
ated to cu. yd. or cy. The full designation is used in discussions where the type of yard might be
in doubt, as where there is a possibility of confusion with square yards or linear yards.
Abbreviations are used in formulas, figuring, and texts where terms are frequently repeated.
Cubic yards may refer to bank, loose, or compacted measure. This will be discussed under
Swell and Shrinkage.
Many dimensions in field measurements and contract plans are in feet, so that if they are mul-
tiplied together to obtain bulk, results are obtained in cubic feet.
These are usually changed to cubic yards by dividing by 27 (there is 27 cubic feet in 1 cubic yard).
Of course it is also possible to divide the original linear measurements by 3 to convert them into
yards, and then multiply, but this may lead to working in fractions, decimals, and mixed numbers.
Most countries use metric measures. See pages A.4 and A.19. One meter is 39.37 inches,
3.2808 feet, or 1.0936 yards. A cubic meter is 35.315 cubic feet or 1.308 cubic yards, a bit less
1
than 1 ⁄ 3 yards.