Source : Webster's Revised Unabridged Dictionary (1913)

Trestlework \Tres"tle*work`\, n.
   A viaduct, pier, scaffold, or the like, resting on trestles
   connected together.

Source : WordNet®

trestlework
     n : a supporting structure composed of a system of connected
         trestles; for a bridge or pier or scaffold e.g.