Basic Civil Engineering PE Flashcards
7 cards from real Civil Engineering PE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Basic Civil Engineering PE flashcards as text
In a soil consolidation test, the time to reach 50% consolidation (t_50) is 10 minutes for a 1-inch thick doubly drained sample. What is the coefficient of consolidation c_v?
Answer: 0.0197 in²/min
c_v = T_50·H_dr²/t_50 = 0.197×(0.5)²/10 = 0.197×0.25/10 = 0.00493 in²/min — using H_dr = 0.5 in (half of 1 in for double drainage) and T_50 = 0.197.
Which type of prestressed concrete system applies prestress after the concrete has hardened and reached adequate strength?
Answer: Post-tensioned
In post-tensioning, steel tendons are stressed after concrete cures, typically using hydraulic jacks against anchorage devices at the member ends.
The design flood for a major highway culvert crossing typically corresponds to which return period?
Answer: 100-year
AASHTO and FHWA guidelines recommend the 100-year (1% annual chance) flood for design of major culverts and bridges on principal highways.
In a CPM schedule, if Activity A has an Early Start (ES) of Day 5, an Early Finish (EF) of Day 12, a Late Finish (LF) of Day 15, the total float is:
Answer: 3 days
Total Float = LF − EF = 15 − 12 = 3 days (or equivalently LS − ES = (15−7) − 5 = 8−5 = 3 days).
In wastewater treatment, the Biochemical Oxygen Demand (BOD) test measures:
Answer: Oxygen required by bacteria to decompose organic matter
BOD quantifies the amount of dissolved oxygen consumed by aerobic biological organisms when decomposing organic matter in a water sample at a given temperature over a specific time period.
A 12-inch diameter concrete pipe flows full with Manning's n = 0.013 and slope S = 0.005. The approximate full-flow discharge Q is:
Answer: 1.70 cfs
A = π(0.5)² = 0.785 ft²; R = D/4 = 0.25 ft; V = (1.486/0.013)(0.25)^(2/3)(0.005)^(1/2) ≈ 2.17 ft/s; Q = 0.785×2.17 ≈ 1.70 cfs.
Which factor does NOT affect the lateral earth pressure coefficient at rest (K_0) for a normally consolidated soil?
Answer: Depth of soil layer
K_0 for NC soil is estimated as 1−sinφ' (Jaky's formula) or via Poisson's ratio; it is a material property and does not change with depth in a uniform deposit.