CSLB General Building (B)Planning and EstimatingMedium
A contractor is reviewing plans for a new school building. The plans show a large, open-span area for a gymnasium. Which of the following structural members would be most commonly used to span such a large distance without intermediate supports?
- AConcrete Lintels
- BSteel I-Beams
- CTrusses (Wood or Steel)
- DStandard Wood Joists
Show answer & explanationAnswer & explanation
Correct answer: C. Trusses (Wood or Steel)
Trusses, whether made of wood or steel, are highly efficient structural forms for spanning long distances with minimal material and without requiring intermediate supports. Their triangulated design effectively distributes loads.
Why the other options are wrong
- A. Concrete lintels are typically used over door and window openings for relatively short spans, not for large open-span areas.
- B. While steel I-beams can span significant distances, for very large open spans like gymnasiums, trusses are generally more efficient and economical.
- D. Standard wood joists are suitable for shorter spans, typically found in residential or smaller commercial applications, not large open spans.
Long-Span Structural Members
For large, open-span areas like gymnasiums, trusses (either wood or steel) are the most common and efficient structural members used to support roofs or floors without intermediate columns.
- Efficiently distribute loads over long distances.
- Lightweight compared to solid beams of similar span.
- Common in gymnasiums, auditoriums, and industrial buildings.
Memory trick: Truss's Triangles Tackle Tough Spans.