04 · Geotechnical & Foundations
Status: Planned
A geotechnical investigation has not yet been performed. The need for one depends on:
- Code triggers (San Diego Building Code Chapter 18)
- Mapped geologic/seismic hazards at the site
- Presence of fill or expansive soils
- Field conditions encountered during excavation
Foundation concept
The current design assumes 9 pier foundations, one for each steel column. Each pier is approximately:
- 24 inch diameter × 36 inch depth
- Reinforced with #4 vertical rebar and #3 spiral ties
- 4 anchor bolts (3/4″ × 18″, epoxy-set) per base plate
- Base plates: 8″ × 8″ × 3/4″ A36 steel
Total concrete: ~3.1 cubic yards | Total excavation: ~5 cubic yards
What a geotechnical report would establish
- Allowable bearing pressure for pier design
- Lateral earth pressure for retaining walls (if any)
- Seismic site class
- Expansive soil potential
- Groundwater depth
- Corrosion potential for steel embedments
The structural engineer will require geotechnical design parameters before finalizing foundation sizes and reinforcement. Whether a full geotechnical report is required or a simpler investigation suffices will be determined through coordination with the City and the structural engineer.