General Contractor License Site Work and Excavation Questions and Answers — Questions and Answers
Question 1: An excavation is planned to be 10 feet deep in Type C soil. According to OSHA standards, what is the maximum allowable simple slope for the sides of this excavation?
- ¾ Horizontal to 1 Vertical (¾H:1V)
- 1 Horizontal to 1 Vertical (1H:1V)
- 1½ Horizontal to 1 Vertical (1½H:1V) (Correct answer)
- Benching is permitted as an alternative to sloping.
Correct answer: 1½ Horizontal to 1 Vertical (1½H:1V)
According to OSHA 29 CFR 1926 Subpart P, for excavations in Type C soil, the maximum allowable simple slope is 1½ horizontal to 1 vertical (34 degrees). Type C is the least stable soil classification, requiring the flattest slope for protection against cave-ins. Benching is not a permissible protective system in Type C soil.
Question 2: What is the standard laboratory test used by geotechnical engineers to determine the optimal moisture content at which a specific soil type will achieve its greatest density when compacted?
- Proctor Compaction Test (Correct answer)
- Sieve Analysis
- Atterberg Limits Test
- California Bearing Ratio (CBR) Test
Correct answer: Proctor Compaction Test
The Proctor Compaction Test (either Standard or Modified) is the established laboratory method for determining the optimal moisture content and maximum dry density of a soil. This data is crucial for ensuring that fill material is properly compacted on site to provide adequate support for foundations, slabs, and pavement.
Question 3: A contractor is preparing to start a new project. To ensure all elevations for foundations, floors, and utilities are accurate, the surveyor establishes a single, stable point of known elevation on the site. What is this reference point called?
- Control Point
- Baseline
- Hub
- Benchmark (Correct answer)
Correct answer: Benchmark
A benchmark is a point of known elevation from which all other vertical measurements on a construction site are referenced. While control points establish horizontal (X,Y) position, a benchmark specifically serves as the datum for vertical (Z) dimensions, ensuring consistent heights throughout the project.
Question 4: A general contractor is beginning site work for a new commercial building in a developed area. What is the legally mandated first step that must be taken to identify and prevent damage to existing underground public utilities?
- Carefully excavate with a backhoe until a utility is found.
- Contact the national "Call Before You Dig" service by dialing 811. (Correct answer)
- Review the original as-built drawings from when the area was first developed.
- Hire a private utility locator to scan the entire property with ground-penetrating radar.
Correct answer: Contact the national "Call Before You Dig" service by dialing 811.
State and federal law requires anyone who plans to excavate to contact their state's one-call utility location service, which is universally accessible by dialing 811. This service notifies member utility companies, who then send locators to mark the approximate location of their underground lines, preventing costly and dangerous utility strikes.
Question 5: According to OSHA regulations for excavation safety (29 CFR 1926 Subpart P), what is the minimum distance that excavated materials, known as spoil, must be placed from the edge of a trench or excavation?
- 1 foot
- 4 feet
- 2 feet (Correct answer)
- There is no minimum distance if a competent person is monitoring the pile.
Correct answer: 2 feet
OSHA standard 1926.651(j)(2) requires that spoil piles and any other materials or equipment be kept at least 2 feet back from the edge of an excavation. This prevents the material from falling or rolling back into the excavation onto workers and reduces the surcharge load on the trench walls, which could contribute to a collapse.
Question 6: Which of the following describes a broad, shallow, and typically vegetated channel designed to manage stormwater runoff by conveying it at a non-erosive velocity and promoting infiltration?
- Swale (Correct answer)
- French Drain
- Catch Basin
- Culvert
Correct answer: Swale
A swale, often grass-lined, is a drainage channel designed to slow the flow of stormwater, guide it to a desired location, and allow for filtration and infiltration into the ground. Unlike a French drain (subsurface), a catch basin (an inlet structure), or a culvert (a pipe under a roadway), a swale is an open, surface-level feature.
General Contractor License Site Work and Excavation Questions and Answers
An excavation is planned to be 10 feet deep in Type C soil.
According to OSHA standards, what is the maximum allowable simple slope for the sides of this excavation?