What does a lightweight I-shaped joist consist of?

A lightweight I-shaped joist typically consists of a top chord, a bottom chord, and web members that connect these chords. This design allows for efficient load distribution and makes the joist both strong and lightweight. The combination of the chords and the web forms an I-beam shape, which maximizes structural integrity while minimizing material use.

In structural applications, this type of joist is favored because it can span longer distances and carry more load compared to solid wood members. The web members, which can be made from materials like metal or engineered wood, provide the necessary support without adding excessive weight. This construction method is particularly advantageous in modern building design, where efficiency and material savings are paramount.

The other options do not accurately describe the composition of a lightweight I-shaped joist. For example, solid wood members would refer to traditional lumber without the engineered design aspects of lightweight joists, while metal framing relates to a different type of structural system altogether. Concrete slabs, on the other hand, refer to flat concrete panels used in constructing floors or roofs, not the specialized framing composition of joists.