DPA screw piles

Screw piles type DPA (Drilling Push Aside) is an in-ground formed and soil-displacing screwed pile system, with only a limited amount of excavated soil (potentially contaminated soil). The production is low-vibration, which is important when producing near adjacent structures that are sensitive to settlements and/or vibrations.

Application

  • Particularly suitable for residential and utility construction, and other new buildings where disturbance to the surrounding area needs to be limited.
  • Suitable for urban renewal projects where foundations must be made vibration-free near adjacent buildings or properties.
  • An alternative to non-soil-displacing screw piles where excavated soil severely contaminates the construction site or cannot be removed or disposed of.
  • Causes less noise disturbance than driven pile systems, making them applicable for the expansion of existing and occupied buildings.
  • Applicable in soil conditions or loadings where a long reinforcement cage is necessary, which can be centrally placed in the pile with the required coverage.

Features

  • Soil-displacing, with only limited excavated soil.
  • Low-vibration, therefore well-suited near adjacent structures sensitive to settlement and/or vibrations.
  • Noise-friendly, resulting in less disturbance to the surroundings and suitable near residences, schools, public buildings, etc.
  • Pile head is poured up to the working level and can be finished above the working level to the desired height.
  • Pile length can be immediately adjusted to the ground conditions: the pile is typically installed to the calculated screw-in level.
  • Adjustments in pile specifications possible until just before work commencement.
  • Batter positions: backward 5:1 / forward 10:1.
  • Loadable both in tension and compression.
  • Pile system is low-vibration.
  • Reinforcement possible along the entire length.
  • Reinforcement is installed in the shaft before concreting.
  • Bearing capacity factors assessed and established from load testing by the Building and Housing Supervision Netherlands committee.
  • Competitive compared to soil-removing piles due to greater bearing capacity and a 'clean' construction site.

Vroom Funderingstechnieken has extensive experience with  DPA screw piles and provides advice on the application possibilities of this pile type and other screw pile systems.

Quality Control

Vroom Funderingstechnieken manufactures DPA screw piles according to a procedure established for Vroom Funderingstechnieken as part of internal quality control, nationally applicable standards, and execution conditions.

Control of Geotechnical Bearing Capacity

DPA screw piles are typically installed to the calculated screw-in depth. The required drilling moment is measured for assessment and recognition of the existing soil conditions.

Control of Pile Technical Bearing Capacity

All DPA screw piles are checked for continuity after pile manufacturing. Additional inspection can visually occur after excavation of the pile head. The concrete quality can additionally be checked by drilling and testing cores from the manufactured piles.

Let Us Advise You

Vroom Funderingstechnieken devotes the utmost care to the creation of our brochures and website. However, no rights can be derived from the content. If you use information from our brochures or our website without verification or further advice from Vroom Funderingstechnieken, you do so at your own risk.

Vroom Funderingstechnieken accepts no liability for the accuracy and/or suitability of the information for the intended application. For questions about the application of our products in concrete projects, we advise you to contact our sales department.

Features

  • Soil-displacing, with only limited excavated soil.
  • Low-vibration, therefore well-suited near adjacent structures sensitive to settlement and/or vibrations.
  • Noise-friendly, resulting in less disturbance to the surroundings and suitable near residences, schools, public buildings, etc.
  • Pile head is poured up to the working level and can be finished above the working level to the desired height.
  • Pile length can be immediately adjusted to the ground conditions: the pile is typically installed to the calculated screw-in level.
  • Adjustments in pile specifications possible until just before work commencement.
  • Batter positions: backward 5:1 / forward 10:1.
  • Loadable both in tension and compression.
  • Pile system is low-vibration.
  • Reinforcement possible along the entire length.
  • Reinforcement is installed in the shaft before concreting.
  • Bearing capacity factors assessed and established from load testing by the Building and Housing Supervision Netherlands committee.
  • Competitive compared to soil-removing piles due to greater bearing capacity and a 'clean' construction site.

Vroom Funderingstechnieken has extensive experience with  DPA screw piles and provides advice on the application possibilities of this pile type and other screw pile systems.

Quality Control

Vroom Funderingstechnieken manufactures DPA screw piles according to a procedure established for Vroom Funderingstechnieken as part of internal quality control, nationally applicable standards, and execution conditions.

Control of Geotechnical Bearing Capacity

DPA screw piles are typically installed to the calculated screw-in depth. The required drilling moment is measured for assessment and recognition of the existing soil conditions.

Control of Pile Technical Bearing Capacity

All DPA screw piles are checked for continuity after pile manufacturing. Additional inspection can visually occur after excavation of the pile head. The concrete quality can additionally be checked by drilling and testing cores from the manufactured piles.

Let Us Advise You

Vroom Funderingstechnieken devotes the utmost care to the creation of our brochures and website. However, no rights can be derived from the content. If you use information from our brochures or our website without verification or further advice from Vroom Funderingstechnieken, you do so at your own risk.

Vroom Funderingstechnieken accepts no liability for the accuracy and/or suitability of the information for the intended application. For questions about the application of our products in concrete projects, we advise you to contact our sales department.

Technical data

Manufacturing

  1. Positioning of the DPA drill with hydraulic drilling motor.
  2. Screw installation rotates clockwise through intermediate soil layers.
  3. Screw installation rotates clockwise to the required depth.
  4. Insertion of reinforcement over the specified length.
  5. Filling the core of the tube with concrete.
  6. Concrete level maintained during manufacturing at a minimum of 1 m above working level. Tube is withdrawn from the ground in a static position or with slight clockwise rotation.
  7. Finishing the pile, if necessary.

Reinforcement

B500B quality.
Pile reinforcement and dimensioning according to load data provided by the structural engineer. Helical stirrup reinforcement ensures a significantly stiffer reinforcement cage, thereby reducing deformation.

Shaft reinforcement is suspended inside the auger tube at the required height prior to concreting.

If applicable, additional head reinforcement is installed immediately after pile installation.

Load-bearing capacity

Pile class factors have been determined based on a nationally recognised self-declaration type A1.

Pile tip bearing factor

αp = 0.27
β = 1.0
The displacement section of the auger tube is screwed into the load-bearing soil layer.

Shaft friction factor

αs = 0.008* over the length of the auger up to halfway through the displacement element
αs = 0.020 over the length from halfway up the displacement element to the top of the load-bearing sand layer

Under specific conditions, αs = 0.020 over the full length is possible; please contact us for further information.

The displacement section of the auger tube is screwed into the load-bearing soil layer.
Tension: αt = 0.009

Load and deformation behaviour

Within the range of service loads, settlement behaviour is equivalent to that of a displacement pile.

Load spectrum

Compression up to approx. 2500 kN.
Tension up to approx. 400 kN.
Vroom Funderingstechnieken can provide guidance on the load-bearing capacity of a DPA pile for a specific soil condition.

Available pile diameters, dimensions in mm

310, 360, 410, 460 and 510*

* seek advice regarding the application of larger pile diameters.

Pile length and applicability depend on soil conditions and pile loads. Installation depth to be assessed for feasibility by Vroom Funderingstechnieken.

Concrete quality

Available in C20/25, C25/30, C30/37 and C35/45 quality.

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