ASCE Structural Engineering and Materials 5 — Questions and Answers
Question 1: Under the NDS for wood design (ASD), what load duration factor CD applies to wind or seismic loads?
- 0.9
- 1.0
- 1.25
- 1.6 (Correct answer)
Correct answer: 1.6
The NDS uses CD = 1.6 for the 10-minute duration of wind and earthquake loads.
Question 2: How does the compressive strength of sawn lumber parallel to the grain compare with strength perpendicular to the grain?
- Parallel is much greater (Correct answer)
- They are equal
- Perpendicular is much greater
- It depends only on moisture
Correct answer: Parallel is much greater
Wood fibers loaded along their length are far stronger than when they are crushed across the grain.
Question 3: What mechanism transfers load in a slip-critical bolted steel connection at service loads?
- Bolt bearing on the hole
- Friction between the faying surfaces (Correct answer)
- Bolt shear only
- Weld fusion
Correct answer: Friction between the faying surfaces
Slip-critical connections use pretensioned bolts, so load passes through friction on the faying surfaces.
Question 4: What is the effective throat of an equal-leg fillet weld with leg size w?
- 0.5w
- 0.707w (Correct answer)
- w
- 1.414w
Correct answer: 0.707w
For a 45° fillet weld, the throat is w·sin45° ≈ 0.707w.
Question 5: At any point on a beam, the slope of the bending moment diagram equals:
- The distributed load intensity
- The shear force (Correct answer)
- The deflection
- The rotation
Correct answer: The shear force
dM/dx = V, so the moment diagram's slope equals the shear at that point.
Question 6: Which principle states that an influence line has the shape of the structure's deflected shape when the response function is released and given a unit displacement?
- Maxwell's reciprocal theorem
- Müller-Breslau principle (Correct answer)
- Castigliano's theorem
- Superposition principle
Correct answer: Müller-Breslau principle
The Müller-Breslau principle builds qualitative influence lines from the released structure's deflected shape.
Question 7: In the ASCE 7 Equivalent Lateral Force procedure, how is the seismic base shear V calculated?
- V = Cs·W (Correct answer)
- V = Ie·W/R
- V = Sds·L
- V = 0.6W
Correct answer: V = Cs·W
V = Cs·W, where Cs is the seismic response coefficient and W is the effective seismic weight.
ASCE Structural Engineering and Materials 5
Under the NDS for wood design (ASD), what load duration factor CD applies to wind or seismic loads?