That bottom section looks like 8 X 8 square tubing on the chords with 6 X 6 square tube on the lacings.......I've not seen a guyed tower built that strong...I never got to work those antennas...I can only guess at how much they weighed...what a shame they came down...
Height and weight of the system
Tower height 100 m (330 ft)
80 m beam 90 m (300 ft)
160 m beam 80 m (270 ft)
Total weight 39 600 kg (80 000 lbs)