In top-down construction, basement slabs are poured as the excavation progresses, with access openings left to excavate beneath. Each completed floor acts as lateral bracing for the perimeter wall system, so the superstructure can proceed simultaneously – saving months on the programme.
Key features
- Perimeter D-wall or pile wall
- Plunge columns
- Slabs as permanent bracing
Applications
- Deep basements in city centres
- Tight programmes
Benefits
- Faster overall programme
- Minimal ground movement
- No temporary struts
