a machine-threaded steel rod used for through-brace installations.
threaded rod (Wikipedia)
A threaded rod, also known as a stud, is a relatively long rod that is threaded on both ends; the thread may extend along the complete length of the rod. They are designed to be used in tension. Threaded rod in bar stock form is often called all-thread (ATR); other namses include fully-threaded rod, redi-rod, continuously-threaded rod, and TFL rod.
Typical profile of a threaded rod with metric screw threads.
Galvanized steel, mild steel, stainless steel, nylon, brass, copper, aluminum, and titanium are all commonly used to make threaded rods.