Which structural element connects the upper and lower parts of a truss?

In the context of truss design and construction, the element that connects the upper and lower parts of a truss is known as the chords. The chords constitute the main structural beams at the top and bottom of the truss, serving crucial roles in tension and compression within the structure. The upper chord typically experiences compressive forces, while the lower chord is subjected to tension.

Webbing refers to the diagonal members that help distribute loads throughout the truss and lock the structure into a stable form, but it does not connect the upper and lower parts. Gussets are often plates used to reinforce joints in trusses, but they don't serve as the primary structural elements connecting the two chords. Flats are usually associated with the flat members of structural frames and don’t specifically relate to truss connections.

Thus, recognizing that the chords are essential for the integrity and function of a truss significantly clarifies their role in structural engineering and design.