Foundation

 

Bored Piles

CFA Bored Piles

Driven H Piles

Advantages

Bored pile are used to support multi-story building or bridges which can producing heavy vertical loads

They are quick to install and have

no requirement for temporary or permanent casings

Driven piles are driven to a set in variable site conditions to achieve uniform minimum capacity with high reliability

Methodology

Pile drilled / soil removed and replaced with reinforced concrete

Auger drilled into ground and replaced with concrete as the auger is removed

Steel section driven into the ground

Design

Effect on adjacent ground

No displacement of the soil but the potential for relaxation / softening adjacent ground, dependant upon the soil and bore support used

Typically no displacement with good construction controls

Localised densification of loose non-cohesive soils.

Small cross sectional area and hence minimal soil displacement or potential improvement

Typical size ranges

450-2500mm diameter

450 – 1200 mm diameter depths up to 32m

150 – 350 UC’s, UBPs

Capacity

- Shaft friction

Medium

Medium

Medium

- End bearing

Very high with enlarged base

Medium

High

- Structural

Very high structural capacity and

stiffness achievable

Cage insertion can limit tensile

and flexural capacity at depth

Driving stresses often govern the steel section required

Durability

Conventional concrete in the ground design

Permanent liner in highly aggressive conditions

Conventional concrete in the ground design

Sacrificial thickness of steel above

low groundwater level

 Construction

Typical / Plant

Hydraulic or crane mounted piling rig, handling crane, casing, vibro with powerpack and / or drilling support fluid plant

Hydraulic piling rig, concrete pump and possible handling crane

Crane, vibro hammer or hydraulic hammer with powerpack or drop hammer and leaders or guide frame

Piling productivity

16m deep - 600dia @ 2No/day in soft material including a 3m soft rock socket depth. Detailed production rates

16m deep - 600dia @ 11No/day in soft material including a 3m soft rock socket depth

16m deep - 350 UC’s @ 22No/day in soft material

Material to Plant

Concrete, reinforcement cages and method dependant material

Concrete and reinforcement cages

Steel sections

Materials storage

Casing and cage lay down area

Cage lay down area

H pile lay down area

Noise

Machine only unless driven casing

Machine only

Yes, if vibro used hammer used to obtain pile set

Vibration

No, unless driven casing used

No

Yes

Spoil

100% Nett volume

100% Nett volume

None

Other

Plunged columns can be placed into the top of the pile to structural positional tolerances

Fast installation process with real time monitoring systems for construction control and records

Full strength welded splice used at connections

Predrilling can be used to overcome obstructions

Driven Tubes Piles

Precast Concrete Piles

Vibro replacement

Advantages

They are ideally suited for marine and other near shore applications with a very high end bearing capability

Precast driven piles can be environmentally friendly when construct temporary trestles in wetland

Stone piles are a very effective technique, for resolving issues with liquefiable soils, that fall within the typical grain size range

Methodology

Tube driven using external or internal hammer and filled with reinforced concrete

Pre cast section driven into the ground

Soil displaced or removed and replaced with stone

Design

Effect on adjacent ground

Large displacement of plugged tubes resulting in densification of non-cohesive soils and enhanced capacity

Large displacement resulting in densification of non-cohesive soils and enhanced capacity

Large displacement with densification of non-cohesive soils surrounding the stone column which enhances the capacity

Typical size ranges

350 – 750 mm diameter

250 – 600 mm square

600 – 1200 mm diameter

Capacity

- Shaft friction

Medium

Medium

Low

- End bearing

Very high

Very High

Low

- Structural

Tubes can be reinforced concrete filled to enhance capacity

Lifting, driving and jointing can limit capacity

Stone quality & confinement in the soil limit the capacity

Durability

Sacrificial thickness of steel and

internal reinforced concrete

Conventional concrete in the ground design Review potential corrosion at joints

Weathering / degradation of stone typically not an issue

Construction

Typical / Plant

Crane, vibro hammer or hydraulic hammer with powerpack or drop hammer, leaders

or guide frame

Crane, hydraulic hammer with powerpack or drop hammer, leaders or guide frame

Crane, vibro probe with power pack,

water pumps, compressor and front loader

Piling productivity

16m deep - 600mm Dia piles @ 22No/day

16m deep - 300mm square piles @ 20No/day

12m deep @ 6No/day in soft material

Material to Plant

Steel tubes, reinforcement cages and concrete

Precast concrete piles unless manufactured on site

Stone

Materials storage

Tube and cage lay down area

Precast pile lay down / curing area

Stone stockpiles

Noise

Yes if top driven but limited if bottom driven

Yes

Machine only

Vibration

Yes

Yes

Yes

Spoil

None, but ground heave possible

None, but ground heave possible

20 - 100% Nett volume

Other

Predrilling can be used to overcome obstructions Enlarged bases can be formed to enhance capacity

Variable pile founding depth can lead to high wastage levels and jointing expensive

Top feed “Wet” process requires water circulation system and settlement ponds to contain silts

 

 

 

Sheet Pile Wall

Secant Pile Wall

Diaphragm Wall

Advantages

Sheet piles are best suited for the following applications temporary retaining walls, cofferdams and other temporary structures

This is a permanent solution which provides increased wall stiffness compared to sheet piles  

Diaphragm walls tend to be used for retaining very deep excavations as they can be designed to take very high structural loads

Methodology

Clutched sheet piles driven into position.

A series of piles installed so that they overlap to form a wall.

A series of interlocking reinforced concrete panels.

Construction

Establishment

Cranes, vibros and hammers and / or pile jacking plant

50-60T self erecting hydraulic drilling rigs and handling crane.

50T crane + grab, handling crane,

mud conditioning plant, mud storage

Piling productivity

16m deep - 600mm wide sheet piles @ 22No/day (in clay or sand materials) Detailed production rates

16m deep - 600dia @ 4No/day in soft material including a 3m soft rock socket depth. Detailed production rates

16m deep by 800mm wide @ 14-40m3/day of completed wall per rig  per day

Materials to site

Sheet Piles

Concrete, reinforcement cages

Bentonite, reinforcement cages or concrete panels

Work face access

Plant & Materials delivery

Plant & Materials delivery

Plant materials and pipelines for mud circulation

Noise

Yes, unless jacked in

Machine only

Machine only

Vibration

Yes, unless jacked in

No

No

Spoil

No

100% nett volume

100% nett volume

Product

Wall Movement

Flexible, can be increased with clutched

king piles. More props or anchors can be

used to reduce movements

In-situ wall with ground supported

throughout construction. Very stiff.

Ground supported throughout excavation. Stiffest option given wall thickness

Watertightness

Good with joint treatment

Groundwater control over pile length and satisfactory performance with some seepages

Excellent over full depth of the wall with

waterbar across panel joints.

Connections

Welded below capping beam level

Drilled & grouted bars into piles,

shear & bending capacity possible

Full moment & shear connection via box-out and pull-out bars

Durability

Internal painting and sacrificial

thickness of steel

Conventional concrete in the ground design. Internal lining for long-term seepage

Conventional concrete in the ground design. No internal lining necessary

Load Capacity

Low end bearing capacity

Capacity can be enhanced by increasing the length of some piles

Wall has a large bearing area and individual

panels can be extended

 

 

 

 

Soldier Pile Wall

Bored Pile Wall

Soilmix/Slurry Wall

Advantages

Soldier pile and lagging walls are the most inexpensive systems compared to other retaining walls. They are also very easy and fast to construct

Low cost and speed of construction for temporary and permanent retaining walls and soil support 

Excellent resistance to contaminated groundwater. They have abilityto adapt to ground movements such as earthquakes

Methodology

Constructed using piles timber infill panels

(timber, steel or concrete)

Series of bored piles installed relatively close together with shotcrete arches

Steel or precast concrete elements placed in fluid soilmix / slurry

Construction

Establishment

50-60T self erecting hydraulic drilling rigs and handling crane

50-60T self erecting hydraulic drilling rigs, handling crane and concrete pumps

50T crane + grab / CSM, handling crane / grout plant with screw feed silos, high pressure pumps

Piling productivity

16m deep - 300mm square piles @ 18No/day

16m deep - 600dia @ 4No/day in soft material including a 3m soft rock socket depth. Detailed production rates

16m deep by 800mm wide @ 20-50m3/day of completed wall per rig  per day

Materials to site

Concrete, reinforcement cages, steel or precast concrete panels

Concrete, reinforcement cages

Cement, bentonite, steel or precast concrete panels

Work face access

Plant & Materials delivery

Plant & Materials delivery

Plant, materials and pipeline delivery of slurry

Noise

Yes, if driven sections

Machine only

Machine only

Vibration

Yes, if driven sections

No

No

Spoil

Dependant on installation method

100% nett volume

30%-80% Nett volume

Product

Wall Movement

Ground unsupported allowing relaxation prior placement of panels and backfilling Stiffness depends on structural section

and backfill compaction

Ground unsupported allowing relaxation prior to concrete

Finished product stiff

Ground supported with stiffness dependant on steel section.

Precast panels can increase stiffness.

Watertightness

Permeable with no groundwater control

below excavation. Seepages long term

Permeable until shotcrete in place with no

groundwater control below. Seepages long term

Good temporary performance due to

replacement with CB slurry but some seepages

Connections

Numerous connection options dependant on materials used

Drilled and grouted bars into piles, shear

and bending capacity possible

Welded to steel sections, shear & bending capacity possible.

Durability

Conventional concrete in the ground

design or sacrificial steel thickness given

long term seepage potential

Conventional concrete in ground design

Sacrificial thickness of steel and internal

lining wall for long-term groundwater seepage

Load Capacity

Capacity can be enhanced by increasing the length of piles.

Capacity can be enhanced by increasing the length of some piles.

Capacity limited by penetration of steel beams

 

 

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