Design Principles Flashcards
7 cards from real ASCE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Design Principles flashcards as text
What factor of safety is typically applied to ultimate bearing capacity to get the allowable bearing pressure for shallow foundations?
Answer: 3.0
Geotechnical practice usually applies FS ≈ 3 to ultimate bearing capacity because soil properties are uncertain.
What minimum factor of safety against sliding is commonly required for a cantilever retaining wall?
Answer: 1.5
A sliding factor of safety of about 1.5 is standard for retaining walls.
In the Rational Method Q = CiA, what does C represent?
Answer: Runoff coefficient
C is the dimensionless runoff coefficient, the fraction of rainfall that becomes runoff.
In US customary units, Manning's equation for velocity is:
Answer: V = (1.49/n) R^(2/3) S^(1/2)
The US-unit Manning equation uses the 1.49 constant, hydraulic radius to the 2/3 power, and slope to the 1/2 power.
What perception-reaction time does AASHTO use to compute stopping sight distance?
Answer: 2.5 s
AASHTO's Green Book uses 2.5 seconds for brake reaction time in stopping sight distance.
Which relationship governs minimum horizontal curve radius design (US units, V in mph, R in ft)?
Answer: R = V²/[15(e + f)]
The point-mass equation R = V²/[15(e + f)] balances superelevation and side friction.
Per Terzaghi's principle, the effective stress in a saturated soil equals:
Answer: Total stress minus pore water pressure
σ' = σ − u; the soil skeleton carries only the stress that pore water does not.