A project requires 2,400 cubic yards of fill material to be compacted to 95% standard Proctor density. If the borrow material has a shrinkage factor of 15%, how many cubic yards of material must be excavated from the borrow pit?
Correct Answer
B) 2,824 cubic yards
With 15% shrinkage, you need 15% more material than the final compacted volume. Required material = 2,400 ÷ 0.85 = 2,824 cubic yards to account for the volume loss during compaction.
Why This Is the Correct Answer
When material has a 15% shrinkage factor, it means the final compacted volume will be 85% of the original excavated volume. To find the required excavation amount, divide the needed compacted volume by the remaining percentage: 2,400 ÷ 0.85 = 2,824 cubic yards. This accounts for the 15% volume loss that occurs during compaction to 95% standard Proctor density.
Why the Other Options Are Wrong
Option A: 2,400 cubic yards
This assumes no shrinkage occurs, which ignores the 15% shrinkage factor. Using 2,400 cubic yards would result in only 2,040 cubic yards of compacted fill (2,400 × 0.85), falling short of the required 2,400 cubic yards.
Option C: 2,760 cubic yards
This incorrectly adds 15% to the required volume (2,400 × 1.15 = 2,760). This approach fails to account for the fact that shrinkage is calculated from the original excavated volume, not added to the final compacted volume.
Option D: 2,040 cubic yards
This represents what you would get if you excavated 2,400 cubic yards with 15% shrinkage (2,400 × 0.85 = 2,040). This is the result of insufficient excavation, not the amount needed to be excavated.
Memory Technique
Remember 'Shrink and Divide': When material shrinks, divide the needed amount by what remains (100% - shrinkage%). For 15% shrinkage, divide by 0.85.
More Project Mgmt Questions
What is the minimum R-value required for wall insulation in Florida Climate Zone 2?
A subcontractor brings a new chemical product to your jobsite. Under the Globally Harmonized System (GHS), what information must be immediately available to workers?
A construction site has a trench that is 8 feet deep in Type B soil. What is the maximum allowable slope ratio for the trench walls without protective systems?
What is the maximum recommended spacing between drywall screws when attaching to wood studs?
Your crew discovers suspected asbestos-containing materials during a renovation project. What is the first action you should take?
A scaffold platform is 12 feet long and 5 feet wide. If the maximum load capacity is 25 pounds per square foot, what is the total weight capacity of this platform?
Which CSI MasterFormat Division would contain specifications for fire-stopping and firesafing materials?
In tilt-up concrete construction, what is the primary advantage of this method over conventional cast-in-place construction?
Which OSHA standard specifically addresses construction industry safety and health regulations?
A structural drawing shows a beam labeled 'W12x26'. What does the '26' represent?
People Also Study
Business & Financial Management
120 questions · 70% to pass
Contract Administration
60 questions · 70% to pass