Presentation on theme: "TOPIC 2: TYPES OF FOUNDATION"— Presentation transcript:
1 TOPIC 2: TYPES OF FOUNDATION WEEK 3FACTORS AFFECTING FOUNDATION SELECTIONTYPE OF SHALLOW FOUNDATIONTYPE OF PILES AND CAPACITY. ADVANTAGES AND LIMITATIONS
2 Learning Outcomes Student should be able to: Discuss criterias for foundation selection(CO2-PO10)Determine type of foundation(CO2-PO10)
3 FUNCTION OF A FOUNDATION To transmit load to the ground without bearing capacity failure and excessive settlement.Bearing Pressure and Bearing Capacity Concept
4 Factors Affecting Foundation Selection Subsurface conditionType and magnitude of loadingType of structureConstraint – vibration, noiseCostTimeLogistic
5 Shallow Foundation- pad footing, strip footing, raft foundationNot more than 3m. A basement though may used shallow foundation if the ground is adequate.Deep FoundationCast in situ pile, driven or jack in pile.
6 Deep Foundation FUNCTION OF PILES Transmit load to deeper depth underneath the structurewhen upper layer of soil too weak to support the load.Resist horizontal force by bending.Anchor a structure subjected to uplifting.Hold a structure where the base is subjected to erosion.
7 Pile classification based on materials - concrete piles – 150RC square pile structural capacity kN, 400x400 – 1980kN- Spun pile – 250mm diameter 460kN, 800mm diameter kN- timber piles- 100kNbakau pile – 10kN, For Sustainability, Government Projects not allowed to use bakau pile.- steel pile- composite pilesPile classification based on installation- Displacement piles : Driven piles, jacked pilesNon displacement piles : Bored pile, micropiles
8 Advantages and limitations of certain type of piles Cost, availability, capacity, suitability for the ground strata, noise, vibration, machineries and rigs.
9 Pile classification based on functions- compression piles- tension piles- batter/rake piles – resist lateral load. Max inclination 4:1 Pile classification based on bearing- end bearing piles- friction piles- partly end bearing and partly friction
10 RAFT FOUNDATIONCovers the entire area under the structure, supporting severalcolumns and wallsFor low bearing capacityPockets of loose soilOr when individual spread footing covers more than 50% area.