Bronze is over 95% copper and the soft metal is not strong enough to support itself when cast in large, heavy monuments. Therefore, a steel armature must be placed inside the sculpture to provide structural support. Imagine a garment hanging from and supported by a coat hanger and one can envision the armature procedure.
Notice the steel bar inserted in the leg in the image below. One panel has not been welded in place to allow the workers access to the steel armature inside the sculpture.
To learn more about this project, start with Post #274.