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Foundation Transfers building loads to ground
- 1.
- 2. Functions Transfers buildingloads to ground Anchors the building against wind and seismic loads Isolates building from expansive soils Holds building above or from ground moisture Retards heat flow to or from conditioned space Provides storage, living, mechanical space (basements)
- 3. Foundation Construction Types Slab on grade Crawl space Basement
- 4. Types of Foundations Shallow/spread foundation 1. Pads/isolated footings 2. Strip footings 3. rafts Deep foundation 1. Piles 2. Pile walls 3. Diaphragm walls 4. Caissons
- 6. Foundation Construction Materials Masonry block Poured concrete Brick Stone Wood Pre-cast Concrete
- 7. Concrete Masonry Unit Causes Water and wet soils Frost Earth loading Differential settlement Missing components Common defects Leaning/tipping Buckled Horizontal displacement Cracks
- 8. Brick Causes Bondor course failure Frost and earth loading Water Sandblasting Improper caulking Common defects Bulging Cracks and bulges Cracks & loose bricks Spalling
- 9. Poured Concrete Causes Dry joint Water, frost Earth loading Lacks footing Poor concrete mix Soil undermining Common defects Cold pour Shrinkage crack Holes and penetrations Leaning Spalling Tie leaks
- 10. Pre-cast Concrete/Modular Causes Incomplete sealing Poor section alignment Inadequate footing drain Excessive spanning Common defects Leaks and water entry Foundation movement
- 11. Stone Causes Waterand wet soils Frost Earth loading Removing sections of wall Dry laid Modernization effects Common defects Dislocations and loose stones Bulges Interruptions and loss of integrity Water leakage
- 13. Wood Common defects Leakage Buckling Horizontal displacement Cracks Causes No moisture barrier Omitted gaskets or sealants
- 14. Types of Piles 1.End bearing piles – carrying capacity is in the hard stratum 2. Friction piles – carrying capacity is from skin friction or adhesion 3. Tension piles –used for structures which are subject to large overturning, e.g. transmission towers, tall chimneys and jetties 4. Laterally load bearing piles – used for wharves and jetties carrying the impact forces of berthing ships, piled foundations to bridge piers, trestles to overhead cranes, tall chimneys and retaining walls, where the horizontal component is relatively large 5. Settlement reducing piles - incorporated beneath the central part of a raft foundation in order to reduce differential settlement 6. Piles in fill - pass through layers of moderately- to poorly-compacted fill will be affected by negative skin friction, which produces a downward drag along the pile shaft and therefore an additional load on the pile
- 15. Types of Piles Endbearing piles Soft compressible soil Hard incompressible soil Friction piles Soft soil becoming increasingly stiff with depth Settlement reducing piles Piles in fill Recent fill Consolidating soil Hard incompressible layer
- 16. Types of PileConstruction Displacement Piles Totally preformed displacement piles Driven and cast in place DP Helical (screw) DP Non-displacement piles Small diameter bored CIP Large diameter bored CIP Partially preformed piles Grout or concrete intruded piles
- 17. Pile materials Pile typeMax. length Optimum length Size Max. capacity Usual spacing Timber 33.5m 20m 25- 50cm 40tons 75cm– 90cm Steel 76m 36m 20cm- 1.20m 3,500 75cm- 2.40m Concrete 60m 24m 25- 50cm 500 90cm- 1.8m composite 60m 45m Up to 88cm 200 90cm- 1.40m
- 18. Method of PileInstallation Dropping weight Diesel hammer Vibratory methods of pile driving Jacking methods of insertion