Civil Engineering PE Basic Civil Engineering PE 4 — Questions and Answers
Question 1: A column with both ends pinned has an effective length factor (K) of:
- 0.5
- 0.7
- 1.0 (Correct answer)
- 2.0
Correct answer: 1.0
A pin-pin column has K = 1.0, meaning the effective length equals the actual unbraced length.
Question 2: In hydrology, the Rational Method formula Q = CiA is used to estimate peak runoff. What are the units of 'i' in US customary units?
- ft/hr
- in/hr (Correct answer)
- ft³/s
- gal/min
Correct answer: in/hr
In the Rational Method, 'i' is the rainfall intensity in inches per hour, 'A' is the drainage area in acres, and Q is in ft³/s (cfs).
Question 3: Terzaghi's general bearing capacity equation for a strip footing on c-φ soil includes which three terms?
- Cohesion, surcharge, and self-weight of soil below footing (Correct answer)
- Cohesion, friction angle, and depth
- Surcharge, water table, and foundation width
- Unit weight, depth, and settlement
Correct answer: Cohesion, surcharge, and self-weight of soil below footing
Terzaghi's equation q_ult = cN_c + qN_q + 0.5γBN_γ accounts for cohesion, overburden surcharge, and the self-weight of the soil wedge.
Question 4: Which ASCE 7 load combination governs for uplift on a roof during a wind event?
- 1.2D + 1.6W
- 0.9D + 1.0W (Correct answer)
- 1.2D + 1.0E
- 1.4D
Correct answer: 0.9D + 1.0W
The combination 0.9D + 1.0W uses minimum dead load to maximize net uplift, which governs when wind causes upward (negative) pressure on a roof.
Question 5: The Hazen-Williams equation is used for:
- Open channel flow calculations
- Pressure pipe flow in water distribution systems (Correct answer)
- Sediment transport in rivers
- Pump cavitation analysis
Correct answer: Pressure pipe flow in water distribution systems
The Hazen-Williams equation (V = 0.849·C·R^0.63·S^0.54) is an empirical formula specifically for pressure flow in water supply and distribution pipes.
Question 6: In roadway design, a vertical curve is used to connect two tangent grades. The length of a crest vertical curve is primarily controlled by:
- Design speed and algebraic difference in grades (Correct answer)
- Pavement type and traffic volume
- Horizontal curve radius
- Superelevation rate
Correct answer: Design speed and algebraic difference in grades
Crest vertical curve length is determined by design speed (which sets sight distance) and the algebraic difference in grades (A = g1 − g2).
Question 7: A steel tension member has a gross area of 6.0 in² and a net area of 4.8 in². Per AISC LRFD, if F_y = 50 ksi and F_u = 65 ksi, which limit state governs the design tensile strength?
- Yielding on gross area: φP_n = 270 kips
- Rupture on net area: φP_n = 187 kips (Correct answer)
- Block shear governs at 200 kips
- Buckling governs at 180 kips
Correct answer: Rupture on net area: φP_n = 187 kips
Yielding: φP_n = 0.90×50×6.0 = 270 kips; Rupture (assuming U=1.0): φP_n = 0.75×65×4.8 = 234 kips — rupture on net area (234 kips) is less, but if U < 1.0 it could be even lower; with A_e = U×A_n, the lower value governs.
Civil Engineering PE Basic Civil Engineering PE 4
A column with both ends pinned has an effective length factor (K) of: