Yay construction questions!!!
A contract has 90 days remaining until completion. Advance completion will be paid $10,000 bonus per
day. The most critical activity duration can be shortened by employing more crews. There is a
reduction in efficiency as the number of crews increase; that is, the number of schedule days saved is
not directly proportional to the number of crews added. For each crew added, the cost is $2800 per
day for labor and equipment. If crews must be added as a complete unit, how many crews can be
added without exceeding the bonus amount? 1
crews added added crew cost per day schedule days reduced
1 $2800 20
2 $5600 26
3 $8400 30
Excavation quantities have been determined from cross sections and must be adjusted for shrinkage.
Tabulated here are the unadjusted volumes required. Shrinkage is 10%. The cut volume increases
18% when hauled in 15 yd3 capacity trucks. How many truckloads of borrow are required? 44
station cut fill
(yd3) (yd3)
20 1500 0
21 1350 0
22 800 500
23 250 950
24 0 1200
25 0 1400
A compacted fill is to be constructed with a total volume of 10 000 m . The fill is to be compacted to a
dry unit weight of at least 20 kN/m and a minimum water content of 10%. Soil in the borrow area has
a dry density of 19.0 kN/m and an average water content of 8%.
The weight of soil solids required to build the fill is most nearly 200,000Kn
A compacted fill is to be constructed with a total volume of 10 000 m . The fill is to be compacted to a
dry unit weight of at least 20 kN/m and a minimum water content of 10%. Soil in the borrow area has
a dry density of 19.0 kN/m and an average water content of 8%.
The amount of borrowed material that must be removed is most nearly 11,000 m3
Asphalt paving operations have been described as a system of four items: batch plant operation,
transporting, placing, and rolling. A contractor has a project that requires critical airport paving in a
strict 40 hr time window. Using equipment matched to the asphalt paver production rate, the
contractor's historical reliability of the equipment is shown in the table.
Due to the critical nature of the project, the contractor has decided to assign a second paver to the
job, while using the same amount of other equipment that would support a single paver. What is the
reliability of the paving system for this project? 0.93
equipment reliability
a batch plant 0.97
b hauling equipment 0.99
c asphalt paver 0.90
d rolling equipment 0.98
An asphalt paving surfacing alternative is being evaluated using the present worth for future
expenditures over an expected 40 yr life. The initial cost of the asphalt surface is $700,000. It will
require overlays at several intervals during the expected life. The cost of the future overlays will be
$252,000 at 10 yr from construction, $332,000 at 17 yr, $420,000 at 23 yr, $530,000 at 29 yr, and
$671,000 in 35 yr. The inflation rate is set at 4% annually for the analysis. What is the present worth
of the asphalt alternative? $1,550,000
