Engineers Test Fire’s Effects on Structural Steel

(Photos8.com)

Researchers in engineering at Purdue University in West Lafayette, Indiana are studying the effects of fire on steel structures, such as buildings and bridges. The research uses a unique heating system and a specialized laboratory for testing large beams and other components.

Building fires may reach temperatures of 1,000 degrees Celsius (1,800 degrees Fahrenheit), say the researchers, which would take exposed steel about 25 minutes to lose about 60 percent of its strength and stiffness. Increasing the steel’s temperature makes it softer and weaker.

One of the team’s projects focuses on how a building’s steel-and-concrete floor and its connections to the building behave in a fire. Another project concentrates on how fire affects steel columns and a building’s frame.

For this research. the Purdue team designed a system made up of heating panels to simulate fire. The panels have electrical coils placed close to the surface of the specimens. As the system is used to simulate fire, test structures are subjected to forces with hydraulic equipment. In addition to the heating panels, the 66,000-square-foot laboratory has special hydraulic testing equipment and overhead cranes. These tools and methods are considered more realistic of the stresses on steel in fires than the usual testing furnances that cannot simulate the additional loads and forces from everyday use.

The research group also has tested 10-by-10-foot composite floor systems made of steel beams supporting a concrete slab inside a furnace operated by Michigan State University. The composite design is the most common type of floor system used in steel structures.

Findings from that research will be compared with floor-system testing to be conducted at Purdue. Results from both experiments will be used to test and verify computational models used to design buildings.

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