NSTM member means what?

• A. A primary steel member entirely in compression with load path redundancy
• B. A secondary member without any tension
• C. Primary steel member at least partially in tension and without load path redundancy
• D. A member that carries only cosmetic loads

Answer: (C)

The idea being tested is that a NSTM member is a primary steel member that is at least partly in tension and lacks a load-path redundancy. In bridge systems, redundancy means there are multiple independent routes for loads to reach the supports. A non-redundant tension member carries load in tension and does not have an alternate path to transfer those forces if it were to fail. That combination—being part of the main load path, experiencing tension, and having no backup path—puts it at higher risk and makes its condition critical to inspect.

So this description is the best fit because it matches all three key aspects: it’s a primary structural member, it’s loaded in tension, and there is no load-path redundancy. The other descriptions either describe compression-only behavior, secondary members that aren’t in tension, or loads that aren’t structural, which do not align with how NSTM members are defined and treated in inspections.