NCARB Structural Systems 1 — Questions and Answers
Question 1: What is the primary function of a building's structural system?
- To transfer all applied loads safely to the foundation and into the ground (Correct answer)
- To provide thermal insulation
- To define the architectural form
- To house mechanical systems
Correct answer: To transfer all applied loads safely to the foundation and into the ground
The structural system's fundamental purpose is to collect gravity, lateral, and environmental loads and transfer them safely through the building into the soil below.
Question 2: In structural engineering, what is the difference between a 'live load' and a 'dead load'?
- Live loads are variable occupancy and use loads; dead loads are permanent self-weight of construction (Correct answer)
- Live loads are wind and seismic; dead loads are snow
- Live loads are only people; dead loads include all finishes
- They are interchangeable terms for gravity loads
Correct answer: Live loads are variable occupancy and use loads; dead loads are permanent self-weight of construction
Dead loads are permanent gravity loads from the building's own weight, while live loads are variable loads from occupants, furniture, and stored materials per IBC tables.
Question 3: Which structural system uses diagonal members to resist lateral forces in a steel frame?
- Braced Frame (Correct answer)
- Moment Frame
- Shear Wall
- Diaphragm
Correct answer: Braced Frame
A braced frame uses diagonal steel members within bays to triangulate the structure, resisting lateral loads from wind and seismic forces through axial action.
Question 4: What is a 'moment frame' in structural design?
- A rigid frame where connections resist rotation, allowing columns and beams to resist lateral loads without diagonal bracing (Correct answer)
- A frame with pin connections at every joint
- A frame designed only for gravity loads
- A concrete shear wall system
Correct answer: A rigid frame where connections resist rotation, allowing columns and beams to resist lateral loads without diagonal bracing
Moment frames resist lateral loads through the bending stiffness of beams and columns with rigid connections, avoiding the need for diagonal bracing that might obstruct architectural openings.
Question 5: Which type of foundation system is most appropriate for a heavy building on soft, compressible soils?
- Deep Pile Foundation (Correct answer)
- Spread Footing
- Grade Beam
- Mat Foundation
Correct answer: Deep Pile Foundation
Pile foundations transfer building loads through weak upper soils to deeper bearing strata or develop capacity through friction along the pile length in soft soils.
Question 6: What does 'tributary area' mean in structural analysis?
- The floor area whose load is carried by a specific beam or column (Correct answer)
- The area of the site covered by the building footprint
- The total roof drainage area
- The cross-sectional area of a structural member
Correct answer: The floor area whose load is carried by a specific beam or column
Tributary area is the portion of a floor or roof that contributes its load to a specific structural member, determined by the geometry of the framing layout.
NCARB Structural Systems 1
What is the primary function of a building's structural system?