Which type of joist features a web that does not fill the entire web space, such as steel bars or tubes?

• A. Solid Web Joist
• B. Open Web Joist
• C. Closed Web Joist
• D. Steel I-joist

Answer: (B)

Open web joists are built with a web that isn’t a single solid panel. Instead, the web is made from individual members (often steel bars or tubes) arranged in a truss pattern, leaving open spaces between them. This design lets utilities like pipes and ducts pass through the joist bay without cutting through a solid web, and it usually keeps the joist lighter while still carrying load.

Solid web joists have a continuous web that fills the space, offering rigidity but making it harder to route through. Closed web joists use web panels that connect the members to form closed cells, reducing the openness compared to open web designs. Steel I-joists use a narrow, continuous web plate between flanges, which fills the space more like a solid member. The description—web members that don’t fill the entire space, often using bars or tubes—best matches the open web joist.