Synonyms for Substructure:

n.

framework, joist, rafter, scaffold, buttress, stanchion, support, frame, gantry. base (noun)
groundwork, foot, ground, infrastructure, support.
basement (noun)
understructure.
basis (noun)
base.
body (noun)
frame.
pedestal (noun)
foundation.
rudiment (noun)
fundament.
substructure (noun)
foundation, foot, groundwork, infrastructure, understructure, fundament, base.
support (noun)
support, buttress, stanchion.

Other synonyms:

subdivision. segment, bit, portion. piece. detail. unit. section. Other relevant words:
frame, portion, section, segment, bit, support, unit, buttress, ground.

Usage examples for substructure

  1. As he advanced he looked about him with an anxious gaze, but it was at the unfloored substructure of the bridge, not at the awesome spectacle of the swift- flowing, ice- covered stream a hundred and fifty feet beneath. – Out of the Primitive by Robert Ames Bennet