Which best describes the structural steel beams when a slab is used?

Which best describes the structural steel beams when a slab is used?

• A. Fairly lightweight, Spaced 3 to 8 feet apart, Frame into heavier steel girders
• B. Very heavy and spanned 12 feet
• C. Are covered with concrete
• D. Have no reinforcement

Answer: (A)

When a concrete slab is used on a structural steel frame, the floor system relies on relatively lightweight beams that are spaced fairly close together—usually about 3 to 8 feet apart. The slab, poured on top of a metal deck, carries part of the load and works with those beams to create a stiff, composite floor. For longer spans, the beams frame into heavier girders, which transfer the load to columns. This setup keeps the beams economical while still providing the needed strength and stiffness. The other options don’t fit as well: long, very heavy beams spanning 12 feet aren’t typical for a slab-on-deck floor, the beams themselves aren’t described as being “covered with concrete,” and there is reinforcement in the concrete slab (and in the connections) rather than a lack of reinforcement.

When a concrete slab is used on a structural steel frame, the floor system relies on relatively lightweight beams that are spaced fairly close together—usually about 3 to 8 feet apart. The slab, poured on top of a metal deck, carries part of the load and works with those beams to create a stiff, composite floor. For longer spans, the beams frame into heavier girders, which transfer the load to columns. This setup keeps the beams economical while still providing the needed strength and stiffness.

The other options don’t fit as well: long, very heavy beams spanning 12 feet aren’t typical for a slab-on-deck floor, the beams themselves aren’t described as being “covered with concrete,” and there is reinforcement in the concrete slab (and in the connections) rather than a lack of reinforcement.