The Critical Role of Foundation Design
Foundations transfer structural dead and live loads safely into the supporting ground. Selecting the right foundation type depends directly on geotechnical characteristics, groundwater levels, structural geometry, and local building codes.
1. Shallow Foundations
Shallow foundations are placed close to the surface and are economical when near-surface soil possesses adequate bearing capacity.
- Pad / Isolated Footings: Support individual columns and point loads.
- Strip / Continuous Footings: Support load-bearing masonry or concrete walls.
- Raft / Mat Foundations: Continuous slabs covering the entire building footprint, distributing loads over weak or variable soils to minimise differential settlement.
2. Deep Foundations
When surface strata are soft, compressible, or prone to volumetric changes, deep foundations transfer loads to deeper, firmer strata or bedrock via:
- Driven Piles: Prefabricated concrete, steel, or timber driven into the ground.
- Bored / Cast-in-Situ Piles: Holes drilled into the soil and filled with reinforcement and concrete.
- Micropiles / Caissons: Specialised elements for restricted access or heavy underpinning.
3. Key Selection Factors
Soil bearing capacity, groundwater table fluctuations, frost depth, seismic zone classification, and adjacent structures all govern the structural decision. A soil investigation report is an indispensable prerequisite before detailing footing dimensions.