lecture 5. pile foundationscontents.kocw.net/kocw/document/2015/hanyang/parkdoohee/... ·...
TRANSCRIPT
© Park 기초공학 lecture_05_pile_foundation
Lecture 5. Pile foundations
Types of pilesSingle piles
Axial CapacityLateral CapacitySettlement
Group pilesDesign of Piles
DefinitionLong, slender structural members that are made of steel, concrete, or timber used to support structural loads
When do we use piles?Used when surface soils are too loose or soft to support shallow foundations safely and economically.
Some conditions that require pile foundations1. One or more upper layers are highly compressible and too weak 2. Subjected to lateral load3. Presence of expansive and collapsible soils
1
© Park 기초공학 lecture_05_pile_foundation
Role of Pile Foundations
2
© Park 기초공학 lecture_05_pile_foundation
Role of Pile Foundations
3
© Park 기초공학 lecture_05_pile_foundation
Types of Pile Foundations 1. Load resisting method
(also called friction piles)
friction piles in sand sometimes called “compaction pile”friction piles in clay sometimes called “floating pile”
4
© Park 기초공학 lecture_05_pile_foundation
Types of Pile Foundations 2. Material
5
© Park 기초공학 lecture_05_pile_foundation
Types of Pile Foundations 3. Mode of installation4. Displacement
6
© Park 기초공학 lecture_05_pile_foundation
Driven Pile 1. Steel Pile
Types of H pile sectionsTable 11.1a page 494
Steel PipesSTK400 / STK490
7
© Park 기초공학 lecture_05_pile_foundation
Driven Pile 1. Steel Pile
Steel Piles
Advantages1. High resistance to handling and driving2. Can be easily cut-off or extended3. Can penetrate hard layers4. High load-carrying capacity
Disadvantage1. Corrosion in marine environment2. High level of noise during pile driving3. Relatively costly
Usual length: 15 – 60 mUsual load: 300 kN – 1200 kN
8
© Park 기초공학 lecture_05_pile_foundation
Driven Pile 2. Precast concrete pile
© Park 기초공학 lecture_05_pile_foundation
Driven Pile 2. Precast concrete pile
Tomlinson (1986)
10
© Park 기초공학 lecture_05_pile_foundation
Driven Pile 2. Precast concrete pile
11
© Park 기초공학 lecture_05_pile_foundation
Driven Pile 2. Precast concrete pile
Advantages1. Can be subjected to hard driving2. Corrosion resistant
Disadvantage1. Difficult to achieve proper cut-off2. Difficult to transport
Concrete pilesUsual length: 10 – 15 mUsual load: 300 kN – 3000 kN
Pre-stressed concrete pilesUsual length: 15 – 45 mUsual load: 7500 kN – 8500 kN
12
© Park 기초공학 lecture_05_pile_foundation
Driven Pile – Driving Hammer
13
© Park 기초공학 lecture_05_pile_foundation
Driven Pile – Driving Hammer
14
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 1. Drilled Shaft
15
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 1. Drilled Shaft
16
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 1. Drilled Shaft
17
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 1. Drilled Shaft
18
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 1. Drilled Shaft
19
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 1. Drilled Shaft
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 1. Drilled Shaft
21
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 1. Drilled Shaft
22
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 1. Drilled Shaft
23
© Park 기초공학 lecture_05_pile_foundation
(a) : straight pier(b) ,(c) : belled pier(d) : straight pier socketed
into rock
피어기초의 종류
Cast in place piles 1. Drilled Shaft
24
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 2. CFA
25
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 2. CFA
26
© Park 기초공학 lecture_05_pile_foundation
Cast in place piles 3. Franki piles
1. Positioning the tube. 2. Compacting the 'plug' into the tube. 3. Bottom drive the tube to the required depth. 4. Forming the enlarged base. 5. Installing the reinforcing cage. 6. Extracting the tube, during or after concreting of the shaft.
Because the driving occurs at the bottom of the tube, the Franki Pile has the lowest noise and vibration levels of the driven pile systems and is suitable where high noise and vibration levels would cause environment problems.
27