Final Answer:
Extruded structural steel used for beams and columns loses 50% of its strength at 1,100 F. (option c)
Step-by-step explanation:
Extruded structural steel used for beams and columns experiences a significant reduction in strength when exposed to high temperatures, losing 50% of its strength at 1,100°F. This information is crucial in the design and evaluation of structures, especially in scenarios where fire resistance is a key consideration. Understanding the impact of temperature on the mechanical properties of structural steel is essential for ensuring the safety and integrity of buildings and other construction projects.
The loss of strength in steel at elevated temperatures is primarily due to the change in its microstructure. As steel is heated, it undergoes a process called tempering, where the material's hardness and strength decrease. At around 1,100°F, structural steel reaches a critical point where it experiences a significant reduction in strength, making it imperative for engineers and architects to carefully consider fire protection measures and material selection in their designs.
This knowledge underscores the importance of incorporating fire-resistant materials and strategies in construction planning, particularly for buildings where the risk of fire is a concern. By understanding the behavior of materials under high temperatures, professionals can implement measures to mitigate potential structural failures and enhance overall safety in the built environment.(option c)