A deck described as a flat, thin steel plate stiffened with closely spaced longitudinal ribs and wearing surface on top belongs to which deck family?

• A. Steel decks
• B. Grid decks
• C. Orthotropic decks
• D. Concrete decks

Answer: (B)

The key idea here is how the deck is built up and stiffened. This description points to a steel deck formed by a flat, thin plate that is strengthened by a dense set of ribs running along the length, with the wear surface placed on top. That grid-like arrangement of longitudinal stiffeners creates a lattice that supports traffic loads while keeping the plate thin, which is the defining feature of a grid deck. The wearing surface on top confirms it’s a steel deck type rather than concrete. In orthotropic decks, you’d typically expect stiffness from ribs in more than one direction to create the orthotropic behavior, whereas this description highlights closely spaced longitudinal ribs forming a grid pattern.