SME
Construction Engineering · Problem type
Overhaul beyond free haul
Use this for “3200 m³ of earth is hauled an average of 450 m, with 150 m of free haul and overhaul paid at $0.85 per m³·sta. What does the overhaul cost?”
Chart
Free haul: 150 m
Overhaul distance: 300 m
This is an example. Type your own values to start a new problem.
dₒ (m)
=
d (m)
−
FH (m)
OH (m³·sta)
=
V (m³)
×
dₒ (m)
100
$
C
=
OH (m³·sta)
×
p ($/(m³·sta))
Formulas
dₒ
=
d
−
FH
300 = 450 − 150
OH
=
V
×
dₒ
100
9,600
=
3,200
×
300
100
C
=
OH
×
p
8,160 = 9,600 × 0.85
Assumptions
•
The haul distance is the centroid-to-centroid distance read off the mass diagram.
•
The contract price for the earthwork covers hauling up to the free-haul distance FH.
•
One station is 100 m (100 ft in US units).
Step-by-step
WE KNOW
V = 3,200 m³, d = 450 m, FH = 150 m, p = 0.85 $/(m³·sta)
FIND
overhaul distance (dₒ), overhaul (OH), overhaul cost (C)
Step 1 · Find overhaul distance (dₒ)
Use dₒ = d − FH
Only the distance past the free haul is paid as overhaul.
dₒ = 450 − 150
dₒ = 300 m
Step 2 · Find overhaul (OH)
Use OH = V × dₒ ÷ 100
Overhaul is volume times the extra distance, counted in stations of 100 m.
OH
=
3,200
×
300
100
OH
=
960,000
100
OH = 9,600 m³·sta
Step 3 · Find overhaul cost (C)
Use C = OH × p
Each cubic metre carried one station past the free haul is paid at the overhaul price.
C
=
9,600
×
0.85
C
=
$8,160
Check
Put the numbers back in. Both sides should match.
300 = 450 − 150 ✓
9,600
=
3,200
×
300
100
✓
8,160 = 9,600 × 0.85 ✓
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