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HomeFoundationsPilesCased CFA piles

Cased CFA piles

Cased continuous flight auger piles are cast in-situ without causing vibrations and noise. They can serve as foundation element, but can also be installed overlapping and thus formin a wall. Pile diameters vary between 360 and 800 mm. Pile loads up to 3000 kN are possible, depending on the soilcondition. An auger in a casing, which can both be independently operated, are screwed into the soil using 2 rotary drills, or a drill and an oscillator. When the desired depth has been reached, the auger and casing are withdrawn and the hole simultaneously filled with concrete. The concrete is poured under slight positive pressure to guarantee a proper construction of the pile shaft. When the auger and the casing have been fully withdrawn, the pile shaft is ready and a rebar cage or steel section can be placed in the fresh concrete. With tubular bored screw piles, the reinforcement can also be installed in the auger before it is being raised and concreted.

Application

Tubular bored screw piles are used as pile foundation or pile wall in locations where vibrations and specially soil settlement should be avoided.

Because the piles are produced inside a casing, the risk of soil relaxation is virtually non-existent, which gives the piles a higher load-bearing capacity than traditional bored screw piles. This makes it possible to produce piles or pile walls close to adjacent structures and foundations. The casing ensures that no soil can enter from below the adjacent structures, which means that there is only a slight risk of settlement damage as a result of the manufacturing process. The pile can also be used as a tensile pile by fitting it with a central rod or steel section along the entire length. Piles used for pile walls are fitted with reinforcement along their entire length, giving this type of wall great stiffness and strength. Because the pressure from liquid mortar exceeds the horizontal soil pressure, the bored pile wall is very stable, allowing its use next to heavily loaded structures. The large strength and stiffness of the concrete pile walls mean it can also be used in deep construction pits with slight deformations. The casing can be left behind in quay walls and loading/unloading jetties, thus creating a foundation in the wet.

Ambient factors

  • Vibration-free and low-noise.
  • Can be installed relatively close to adjacent structures.
  • No pile storage needed 

Pros and Cons

  • The system produces little noise and vibrations and is capable of absorbing tensile as well as compressive loads. By drilling the piles next to each other or in an overlapping design, construction pit walls with great stiffness and slight risk of damage can be produced.
  • The strength/stiffness ratio is superior to that of, for instance, steel sheet piling.
  • The piles have a large penetration capacity and can be used in hard soil layers. 

Applicated

Name of project

Client

Lekkerkerk, Riverbank reinforcement Nederlek

Waterauthority Schieland - Krimpenerwaard

Rotterdam Europoort, Extension motorway A15

Rijkswaterstaat

Emmen, Foundation plant

Akzo

Arnhem, Offices Velperplein

Wessels Zeist

Oosterhout, Quay wall Ancofer

Van Hattum en Blankevoort

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