Final answer:
The critical temperature for steel trusses is 900°F (482°C) when steel significantly loses its structural integrity. This temperature is crucial for structural safety during fires. The correct option is C. 900°F (482°C).
Step-by-step explanation:
The critical temperature for steel trusses can significantly impact the structural integrity and stability of steel constructions.
When steel reaches its critical temperature, its strength can be severely compromised, leading to potential failure under load. The correct answer to the question regarding the critical temperature for steel trusses is C. 900°F (482°C).
This is the temperature range at which steel begins to lose its structural integrity significantly. Although the initial temperature of the rebar was 248°C in the given example, this specific temperature is unrelated to the critical temperature of steel trusses in a building's structure.
During fires, structural engineers must consider the impact of rising temperatures on the steel components to prevent catastrophic failures. The correct option is C. 900°F (482°C).