Which type of truss is supported by the top chord?

In the context of trusses used in construction, an underslung truss is specifically designed to be supported by its top chord. This type of truss typically hangs beneath a primary structure and allows for a more flexible space beneath, which can be advantageous in certain architectural applications.

The top chord of an underslung truss bears the load and provides the necessary support while the bottom chord and webbing help to distribute forces throughout the structure. This design is beneficial in situations where lower vertical clearance is needed, and it ensures efficient load transfer without interfering with the lower spaces.

Understanding the other options can provide clarity on why the underslung truss is distinct. Overhung trusses typically extend beyond their supports and may not necessarily be supported solely by the top chord. A king post truss primarily uses a vertical member (the king post) that connects to the horizontal top chord and bottom chord, which serves a different structural purpose. Scissor trusses have an intersecting design that creates a vaulted ceiling effect, supporting load through both upper and lower chords rather than relying on just the top chord for support.