3.1 Context
Consultation for development of basement structure beneath existing 1960’s residential building.
Primary contact for all parties and effective project manager.
Existing concept design for basic concrete basement walls.
Project site on mountainside - extreme slopes. Soil excavation undermines the building and adjacent properties. Constructability was the main challenge; concept design revolved almost completely around constructability. Investigation into potential foundation systems, construction methodologies, consultation with piling contractors.
3.2 Concept Design & Constructability
- Slope stability analyses
- Scala, borehole and CPT testing across site
- Methodology:
- Demolish front portion of structure, allowing plant access to building
- Install secant walls within existing structure
- Retains soil behind existing building and adjacent properties
- ECI with piling specialist.
- Utilise small piling rig to fit within building
- Demolish existing flooring and install steel beams
- Acting as both temporary propping, and permanent replacement for existing timber piles supporting structure above
- Finally possible to excavate soil beneath building
- Further constructability challenges regarding installation of drainage
- Utilise weepholes and internal drainage system
- Shotcrete to form basement walls
- Concept drawings done on Bluebeam
- Project put on hold due to financing issues after early contractor involvement. Construction was deemed too expensive. Expected to resume design in 2023.