Building Engineering Building Engineering MCQ 3 — Questions and Answers
Question 1: In HVAC design, what does 'sensible heat ratio' (SHR) represent?
- The ratio of latent heat to total heat in an air stream
- The ratio of sensible heat to total (sensible + latent) heat load (Correct answer)
- The efficiency of a heat exchanger
- The ratio of supply air to return air volume
Correct answer: The ratio of sensible heat to total (sensible + latent) heat load
SHR is the proportion of sensible cooling to total cooling load, indicating how much of the load involves temperature change versus moisture removal.
Question 2: What does the R-value of insulation measure?
- Thermal conductance per unit area
- Thermal resistance to heat flow per unit area (Correct answer)
- Moisture permeability of the material
- Fire resistance rating in hours
Correct answer: Thermal resistance to heat flow per unit area
R-value (h·ft²·°F/BTU) measures a material's resistance to conductive heat flow; higher R-values indicate better insulating performance.
Question 3: What is the purpose of a 'control joint' in masonry construction?
- To connect masonry to the structural frame
- To create a pre-defined plane of weakness preventing random cracking (Correct answer)
- To allow vertical movement between floors
- To anchor ties between wythes of a cavity wall
Correct answer: To create a pre-defined plane of weakness preventing random cracking
Control joints are intentional weakened planes in masonry that concentrate shrinkage and thermal cracking at predictable locations.
Question 4: Which foundation type is most appropriate when soil bearing capacity is very low and loads must be transferred to deeper, competent strata?
- Spread footing
- Mat foundation
- Pile foundation (Correct answer)
- Strip footing
Correct answer: Pile foundation
Pile foundations transfer building loads through weak upper soils to deeper bearing strata via end bearing or skin friction.
Question 5: In structural steel, what is the difference between a 'compact' and 'non-compact' section?
- Compact sections are heavier; non-compact sections are lighter
- Compact sections can reach full plastic moment without local buckling; non-compact sections cannot (Correct answer)
- Compact sections require no fireproofing; non-compact sections do
- Compact sections have higher yield strength than non-compact sections
Correct answer: Compact sections can reach full plastic moment without local buckling; non-compact sections cannot
Compact sections have width-to-thickness ratios below limits that allow full plastic hinge formation; non-compact sections experience local buckling before full plasticity.
Question 6: What is the primary benefit of post-tensioning concrete compared to conventional reinforced concrete?
- Eliminates the need for formwork
- Allows longer spans and thinner slabs by introducing compressive prestress (Correct answer)
- Provides greater fire resistance
- Eliminates the need for aggregate in the mix
Correct answer: Allows longer spans and thinner slabs by introducing compressive prestress
Post-tensioning applies compressive force via stressed tendons after concrete cures, counteracting tensile stresses and enabling longer spans with less material.
Question 7: According to OSHA, what is the minimum height at which fall protection is required for construction workers on walking/working surfaces?
- 4 feet
- 6 feet (Correct answer)
- 10 feet
- 15 feet
Correct answer: 6 feet
OSHA 29 CFR 1926.502 requires fall protection for construction workers at heights of 6 feet or more above a lower level.
Building Engineering Building Engineering MCQ 3
In HVAC design, what does 'sensible heat ratio' (SHR) represent?