What is the lower structural member of a truss called?

The lower structural member of a truss is referred to as the chord. In the context of truss design, chords are the main load-bearing beams that form the top and bottom of the truss structure. The upper chord supports loads coming down from the roof or other structures above, while the lower chord helps to distribute the weight and provide structural stability.

Each chord helps define the overall shape of the truss and plays a crucial role in transferring loads to the vertical members, or web members, such as panels and braces. While 'beam' might seem related, it generally indicates a broader category of structural elements supporting loads, and does not specifically refer to the lower member of a truss. The term 'panel' describes the sections between the chords and is not used to denote structural members like the chords themselves. 'Brace,' on the other hand, refers to diagonal members within the truss that provide additional support and stability, but again, it is distinct from what is designated as the chord. Thus, the term 'chord' is the key identifier for the lower structural member of a truss.