Building Engineering Building Engineering MCQ 2 — Questions and Answers
Question 1: What is the primary purpose of a vapor barrier in wall assemblies?
- To improve thermal insulation
- To prevent moisture diffusion into the building envelope (Correct answer)
- To increase structural rigidity
- To reduce air infiltration through cracks
Correct answer: To prevent moisture diffusion into the building envelope
A vapor barrier resists the diffusion of water vapor through wall assemblies, preventing condensation within the assembly.
Question 2: Which ASTM standard governs testing of concrete compressive strength using cylindrical specimens?
- ASTM C39 (Correct answer)
- ASTM C150
- ASTM C494
- ASTM C1064
Correct answer: ASTM C39
ASTM C39 is the standard test method for compressive strength of cylindrical concrete specimens.
Question 3: In steel construction, what does the term 'moment of inertia' primarily describe?
- The resistance of a section to torsional forces
- The resistance of a cross-section to bending about an axis (Correct answer)
- The ratio of stress to strain in elastic range
- The maximum load a column can carry
Correct answer: The resistance of a cross-section to bending about an axis
Moment of inertia (I) quantifies how a cross-section's area is distributed relative to an axis, determining its bending resistance.
Question 4: What is the function of an expansion joint in a concrete slab?
- To reinforce the slab at high-stress zones
- To allow thermal expansion and contraction without cracking (Correct answer)
- To provide drainage channels in the slab
- To anchor the slab to the subgrade
Correct answer: To allow thermal expansion and contraction without cracking
Expansion joints separate sections of concrete so they can move independently due to temperature changes, preventing uncontrolled cracking.
Question 5: According to IBC, what is the minimum live load for office occupancies?
- 25 psf
- 40 psf (Correct answer)
- 50 psf
- 80 psf
Correct answer: 40 psf
The IBC specifies a minimum uniform live load of 50 psf for office areas, though 40 psf is used by some older codes; IBC Table 1607.1 lists 50 psf for offices.
Question 6: What is 'punching shear' in flat slab design?
- Shear failure along the full span of a beam
- A localized shear failure around a column penetrating through a slab (Correct answer)
- Diagonal tension cracking in a wall
- Shear stress from lateral wind forces
Correct answer: A localized shear failure around a column penetrating through a slab
Punching shear occurs when a concentrated load (column) causes the slab to punch through locally, forming a cone-shaped failure surface.
Question 7: Which factor does NOT affect the wind pressure on a building per ASCE 7?
- Building height
- Exposure category
- Soil bearing capacity (Correct answer)
- Building shape coefficients
Correct answer: Soil bearing capacity
Soil bearing capacity is a geotechnical property unrelated to wind pressure calculations; ASCE 7 wind loads depend on height, exposure, and shape.
Building Engineering Building Engineering MCQ 2
What is the primary purpose of a vapor barrier in wall assemblies?