Foundation Engineering Overview

Study Notes

Foundation engineering is a branch of geotechnical engineering.
It applies principles of soil mechanics, structural engineering, and serviceability to design and construct foundations for onshore, offshore, and inland structures.
Foundation engineering is more of an "artistic" approach rather than a routine process, focusing on efficient performance throughout the project's lifetime.

Soil types are categorized as coarse-grained, fine-grained, organic soils, and peat.
Each category has unique subgroups and characteristics.
The system doesn't describe moisture or density characteristics of freshly sampled soil.

Coarse-grained soil includes rock, soil, paper, or material with larger pieces than usual.
Examples include sugar, peridotite, and linen.

Peat is a problematic soil in civil and environmental engineering.
Formed by the accumulation and decomposition of organic materials (from plant remains in waterlogged environments).
Peat soil lacks oxygen during its formation.

Type A soil: Cohesive soils with an unconfined compressive strength of 1.5 tons per square foot (tsf) or greater.
- Examples include clay, silty clay, sandy clay, clay loam, and silty clay loam, and sandy clay loam.
Type B soil: Cohesive soils with an unconfined compressive strength between 0.5 and 1.5 tsf.
- Examples include angular gravel, silt, silt loam, and fissured or vibration-prone soils.
Type C soil: Cohesive soils with an unconfined compressive strength of 0.5 tsf or less.
- Includes granular soils like gravel, sand, loamy sand, and submerged soil/rock prone to seepage.

Auger: Used for drilling foundation piles, particularly in loose rock.
Triaxial Test Apparatus: Assesses material strength, deformation, and stability in engineering projects.
pH meter: Measures hydrogen ion activity (acidity/alkalinity) in solutions, ranging from 1 to 14.
Consolidation Apparatus and Soil Testing: Determines the rate and magnitude of soil consolidation under axial load.
Soil Grinder: Reduces agglomerations of caked soil into individual grains to provide repeatable results.
Direct Shear 11: Tests a square prism of soil laterally restrained and sheared along a horizontal plane under pressure perpendicular to the shearing plane.
Liquid Limit Device: Determines the moisture content where clay soil transitions from plastic to liquid state.
Compression Proving Ring: Measures force in a known-diameter elastic ring.

Shallow foundations are embedded 1-2 meters beneath the final elevation.
- Spread footings: Common type for supporting walls or columns.
  - Distribute loads over a wider area to reduce stress on the soil.
- Slab-on-grade footings: Concrete slab placed directly on the ground to transfer building loads.

Deep foundations transfer loads to stronger soil layers, bedrock or other stable soil.
- Examples: Piles (driven or drilled), caissons, piers and helical piles.

Soil Investigation: Determines the stratigraphy and physical properties of the soil.
Seismic Considerations: Foundation design accounting for dynamic loading (earthquakes) in earthquake zones.

Steel: The most common, provides good strength and durability.
Fiberglass: Lightweight, corrosion-resistant for environments with high moisture or chemicals.
Stainless Steel: More expensive, corrosion-resistant for structures exposed to corrosives.
Galvanized: Protection against corrosion, using a zinc coating over the steel.
Epoxy-coated: Another type with corrosion resistance.

Bar supports and spacing are related to rebar size and type of the slab/structure being placed.
Bar tying (using wires to hold them in place) is important for structural stability and preventing movement.

Increased strength and durability: Rebar adds tensile strength, preventing cracking.
Improved load distribution: Rebar's ability to spread weight reduces uneven settlement.
Crack control: Rebar reinforces the concrete and reduces crack frequency.
Enhanced structural integrity: Rebar strengthens joints making the structure tighter and more stable.
Compliance with building codes: Using rebar ensures safety and avoids penalties.