Answer :
Final answer:
A steel beam bending under fire indicates imminent failure due to loss of structural integrity from high heat. This can lead to collapse. Rusting also weakens steel, but it is a much slower chemical reaction with oxygen.
Explanation:
The observation of a steel beam bending under fire suggests imminent failure of the structure. When steel is exposed to high heat, like that from a fire, it loses its strength and stiffness, which can result in bending or deformation. This bending signifies that the steel’s structural integrity is compromised, and the beam can no longer carry the load it was designed for, leading to the potential for collapse if the fire continues or the load increases. Rusting, as seen on corroded beams, is another issue that causes steel to weaken, though this is a much slower process, and it occurs through a chemical reaction with oxygen, not through exposure to high temperatures.