NASCLA Accredited Commercial General ContractorMetalsMedium
A steel erector is preparing to install a large, complex roof truss assembly. Before lifting, the erector must ensure that the assembly is rigid enough to withstand handling and lifting stresses without permanent deformation. Which of the following is crucial for achieving this required rigidity in the fabricated assembly?
- AUsing specialized lifting slings made of synthetic fibers.
- BApplying a high-gloss protective coating to all surfaces.
- CEnsuring all primary connections are fully bolted or welded as per shop drawings.
- DTemporarily bolting all secondary members with light gauge fasteners.
Show answer & explanationAnswer & explanation
Correct answer: C. Ensuring all primary connections are fully bolted or welded as per shop drawings.
The rigidity of a fabricated steel assembly, especially a complex truss, primarily comes from its properly executed connections. Ensuring all primary connections are fully bolted or welded according to the design is fundamental to achieving the intended structural integrity and rigidity needed to resist handling and lifting stresses.
Why the other options are wrong
- A. Lifting slings are important for safe lifting, but they do not contribute to the internal rigidity of the steel assembly itself.
- B. Protective coatings are for durability and aesthetics, not structural rigidity during handling.
- D. Temporary bolting of secondary members might help with some stability but is not the primary factor for the overall rigidity of a complex truss assembly during a lift; primary connections are key.
Fabricated Assembly Rigidity
The ability of a pre-assembled steel component (e.g., truss, girder) to maintain its intended shape and structural integrity under its own weight and handling forces during lifting and erection.
- Achieved through properly designed and executed connections (welds, bolts).
- Crucial for safe and efficient erection.
- Prevents deformation, buckling, or failure during transport and lifting.
Memory trick: Rigid Assembly: Ready Connections, Resists Rips.