Building Engineering Building Civil Engineering 5 — Questions and Answers
Question 1: What is the purpose of 'camber' built into a steel beam before installation?
- Increase the beam's shear capacity
- Offset anticipated dead-load deflection so the beam remains level in service (Correct answer)
- Reduce thermal expansion effects
- Improve connection resistance at beam ends
Correct answer: Offset anticipated dead-load deflection so the beam remains level in service
Camber is a slight upward pre-bend applied to a steel beam so that dead load deflection brings it back to a level position.
Question 2: According to the ACI 318 building code, what is the minimum specified compressive strength (f'c) commonly used for structural concrete?
- 1,500 psi
- 2,500 psi
- 3,000 psi (Correct answer)
- 5,000 psi
Correct answer: 3,000 psi
ACI 318 sets 3,000 psi as the general minimum f'c for structural concrete in buildings, though higher strengths are common in practice.
Question 3: What is 'consolidation settlement' in fine-grained soils?
- Immediate settlement from elastic compression of soil grains
- Time-dependent settlement as excess pore water pressure dissipates under sustained load (Correct answer)
- Settlement caused by soil erosion or piping
- Sudden settlement from earthquake shaking
Correct answer: Time-dependent settlement as excess pore water pressure dissipates under sustained load
Consolidation settlement occurs as excess pore water slowly drains from clay or silt, allowing the soil skeleton to compress over time.
Question 4: Which type of structural diaphragm transfers lateral loads to vertical elements by acting as a horizontal plate?
- Collector element
- Drag strut
- Floor or roof diaphragm (Correct answer)
- Transfer beam
Correct answer: Floor or roof diaphragm
A floor or roof diaphragm acts like a horizontal plate that collects and transfers lateral loads to shear walls or frames below.
Question 5: What does 'LRFD' stand for in structural engineering design?
- Load Reduction Factor Design
- Load and Resistance Factor Design (Correct answer)
- Lateral Resistance and Force Distribution
- Live-load Reduction Factor Diagram
Correct answer: Load and Resistance Factor Design
LRFD stands for Load and Resistance Factor Design, a probabilistic design approach that applies separate factors to loads and to material resistance.
Question 6: What is the purpose of 'expansion joints' in a large concrete building?
- Connect adjacent structural frames
- Allow for movement due to thermal expansion and contraction (Correct answer)
- Transfer shear between floor slabs
- Provide access for post-tensioning tendons
Correct answer: Allow for movement due to thermal expansion and contraction
Expansion joints are gaps in a structure that allow sections to move independently, preventing cracking caused by thermal expansion, contraction, or differential settlement.
Question 7: In building construction, what is the 'critical path' in project scheduling?
- The safest route through the construction site
- The sequence of dependent tasks that determines the minimum project duration (Correct answer)
- The list of tasks with the largest budget allocation
- The order in which inspections must be completed
Correct answer: The sequence of dependent tasks that determines the minimum project duration
The critical path is the longest sequence of dependent activities, and any delay on it directly delays the overall project completion date.
Building Engineering Building Civil Engineering 5
What is the purpose of 'camber' built into a steel beam before installation?