Civil Engineering PE Prep 5 β Questions and Answers
Question 1: The OSHA standard for fall protection in construction requires guardrails or other protection when workers are exposed to a fall hazard of at least:
- 6 feet (Correct answer)
- 4 feet
- 10 feet
- 8 feet
Correct answer: 6 feet
OSHA 29 CFR 1926.502 requires fall protection for construction workers at 6 feet above a lower level.
Question 2: A cantilever retaining wall has a heel slab that is designed primarily to resist:
- Overturning moment and provide base resistance using soil weight above the heel (Correct answer)
- Shear from the footing toe
- Lateral pile loads
- Frost-heave uplift only
Correct answer: Overturning moment and provide base resistance using soil weight above the heel
The heel slab extends under the retained fill so that soil weight above it contributes to overturning resistance.
Question 3: Manning's roughness coefficient (n) for a smooth concrete open channel is typically about:
- 0.013 (Correct answer)
- 0.025
- 0.035
- 0.050
Correct answer: 0.013
Smooth formed concrete typically has n β 0.013 in Manning's equation for open channel flow.
Question 4: In a CPM network, the Late Start (LS) of an activity is computed as:
- Late Finish (LF) minus activity duration (Correct answer)
- Early Start (ES) plus activity duration
- Late Finish (LF) plus total float
- Early Finish (EF) minus free float
Correct answer: Late Finish (LF) minus activity duration
LS = LF β duration; this is the backward-pass calculation in CPM scheduling.
Question 5: In soil mechanics, the coefficient of lateral earth pressure at rest (K0) for a normally consolidated clay is approximated by:
- K0 = 1 β sin Ο' (Correct answer)
- K0 = sin Ο'
- K0 = cosΒ²Ο'
- K0 = tanΒ²(45 + Ο'/2)
Correct answer: K0 = 1 β sin Ο'
Jaky's formula K0 = 1 β sin Ο' applies to normally consolidated soils.
Question 6: A highway vertical curve connects a +3% grade with a β2% grade. The algebraic difference in grades (A) is:
- 5% (Correct answer)
- 1%
- β5%
- 2%
Correct answer: 5%
A = g1 β g2 = 3% β (β2%) = 5%; A is always taken as the absolute algebraic difference.
Question 7: The purpose of a dewatering system during deep excavation is to:
- Lower the groundwater table to prevent seepage, heave, and instability (Correct answer)
- Remove surface runoff only
- Increase soil bearing capacity permanently
- Prevent frost penetration
Correct answer: Lower the groundwater table to prevent seepage, heave, and instability
Dewatering lowers piezometric levels to stabilize excavation walls and prevent bottom heave and piping.
Civil Engineering PE Prep 5
The OSHA standard for fall protection in construction requires guardrails or other protection when workers are exposed to a fall hazard of at least: