A construction system for joist girders, includes a pair of opposing bi-planar sheets of structural material, each bi-planar sheet having two alternating series of vertical segments, each segment of the series, in horizontal cross-section, defining a planar base parallel to a base of a successive vertical segment of the alternating series of vertical segments, the bases of each segment of the series integrally connected to each other by sidewalls. Respectively upper and lower horizontal track members define in transverse cross-section, a substantially U-shaped geometry, each track member open-ended for horizontally enclosing and securing an upper edge of each bi-planar sheet of the pair of bi-planar sheets. Several vertical tubular members define, in transverse cross-section, a geometry of a rectangle, said tubular members disposed between the pair of bi-planar sheets and nested within corrugated thereof. Tubular horizontal members each having a partially cut-out lower surface are proportioned for engagement about respective edge areas of the bi-planar sheets.