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
A retaining wall must resist an active earth pressure. Using Rankine's theory with φ = 30° and γ = 120 pcf, the active pressure coefficient K_a is:
Answer: 0.333
K_a = (1−sin φ)/(1+sin φ) = (1−0.5)/(1+0.5) = 0.5/1.5 = 0.333 for φ = 30°.
Which type of flow is characterized by a Reynolds number less than 2,000 in pipe flow?
Answer: Laminar flow
Laminar flow occurs when Re < 2,000, where fluid moves in smooth parallel layers with no lateral mixing.
In a triangular traffic flow diagram, what is represented by the slope of the line from the origin to any point on the flow-density curve?
Answer: Space mean speed
The slope of the line from the origin to any point on the q-k curve equals q/k, which by the fundamental equation equals space mean speed (u_s).
The modulus of elasticity (E) for structural steel per AISC is:
Answer: 29,000 ksi
AISC specifies E = 29,000 ksi (200 GPa) as the modulus of elasticity for all structural steel grades.
A concrete mix design has a water-cement ratio (w/c) of 0.45. Increasing the w/c ratio to 0.60 will primarily:
Answer: Decrease compressive strength
Higher w/c ratios produce more porous cement paste with lower compressive strength per Abrams' water-cement ratio law.
In highway design, the stopping sight distance (SSD) depends on which two primary components?
Answer: Brake reaction distance and braking distance
SSD = brake reaction distance (driver perception-reaction time × speed) + braking distance (kinematic braking equation).
Which consolidation parameter represents the rate at which excess pore water pressure dissipates in a saturated clay?
Answer: Coefficient of consolidation (c_v)
The coefficient of consolidation (c_v) governs the rate of consolidation settlement by controlling pore water pressure dissipation.