Your crew is excavating a trench that is 8 feet deep in Type C soil. What is the minimum allowable slope ratio for the sides of this excavation?
Correct Answer
D) 1½:1 (34°)
For Type C soil (the least stable), OSHA requires a minimum slope ratio of 1½:1 (34 degrees from horizontal). This provides adequate protection against cave-ins in unstable soil conditions.
Why This Is the Correct Answer
OSHA 29 CFR 1926.652 specifies that Type C soil, being the least stable soil classification, requires the most conservative slope ratio of 1½:1 (34 degrees from horizontal). This means for every 1.5 feet of horizontal distance, the excavation can drop 1 foot vertically. Type C soils include granular soils, submerged soil, and soil from which water is freely seeping, all of which are prone to cave-ins and require maximum slope protection.
Why the Other Options Are Wrong
Option B: 1/2:1 (63°)
1/2:1 (63°) is too steep for any soil type and would create an extremely dangerous excavation prone to cave-ins, especially in unstable Type C soil.
Option C: 1:1 (45°)
1:1 (45°) is the required slope ratio for Type B soil (medium stability). While safer than options A and B, it's still not conservative enough for Type C soil conditions.
Memory Technique
ABC = Always Be Conservative: Type A = 3/4:1, Type B = 1:1, Type C = 1½:1. Or remember 'Type C = Can't be too Careful' - needs the flattest slope at 1½:1.
Reference Hint
OSHA 29 CFR 1926.652 - Requirements for protective systems, Table B-1 in Appendix B for maximum allowable slopes
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