Superstructure refers to visible parts of buildings or constructions, not the hidden base. You can only see the superstructure of the skyscraper; its foundations are underground.
Pro Tip 2/3
Above Ground Level
It's the section above ground, especially in constructions like bridges or buildings. Floods damaged the base but left the superstructure of the bridge intact.
Pro Tip 3/3
Construction Focus
Use 'superstructure' in a technical context, like architecture or engineering. The architect discussed the superstructure needed to support the new dome.