DPA-combi screw piles

Screw piles of type DPA-combi are a soil-displacing screw pile system formed in the ground and equipped with a prefabricated pile core. The soil is displaced laterally, so only the drill pipe contains a limited amount of released drilling soil. The production process is low-vibration, which is important when working near buildings that are sensitive to damage from settlements and/or vibrations.

Application

  • Can be particularly applied in residential construction, commercial construction, and other new developments where disturbance to the surroundings needs to be minimized.
  • Are suitable for urban renewal projects where low-vibration foundations are required near adjacent buildings or structures.
  • Are an alternative to non-soil-displacing screw piles and grout injection piles, where released soil or grout severely contaminates the construction site or where released soil cannot or may not be removed.
  • Suitable for underground construction. For example, parking garages, basements, and tunnel structures that need to be built from a higher level down.
  • Generate less noise pollution than driven pile systems, making them applicable for the expansion of existing and in-use buildings.
  • Are applicable in soil conditions or loads where the possibility of washing out a pile formed in the ground is considered realistic.

Characteristics

  • Displaces soil, with only limited emerging drilling soil at the drill pipe and ground level.
  • Low vibration, making it suitable for use near buildings that are sensitive to damage from settlements and/or vibrations.
  • Noise-friendly, resulting in less disturbance to the surrounding area, and suitable for use near homes, schools, public buildings, etc.
  • Pile head is suspended below the working level.
  • Pile length can be directly adjusted to the soil conditions.
  • Adjustments in pile specifications are possible up to the ordering moment of prefab elements.
  • Batter piles available upon request and depending on the situation and pile length.
  • Can be loaded both in tension and compression.
  • Prestressed reinforcement over the entire length.
  • The pile system is known and accepted by the Building and Housing Supervision service and engineers, as well as in Building Standards. Competitive compared to soil-removing and grout-injected piles due to soil-displacing execution, required bearing capacity, and a 'clean' construction site.

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

Quality Control

Vroom Funderingstechnieken manufactures DPA-combi screw piles according to an implementation procedure drawn up for Vroom Funderingstechnieken within the framework of internal quality control, national standards, and execution conditions.
The grout is sourced from certified concrete plants. The prefab concrete elements are produced and supplied by certified manufacturers.

Verification of Geotechnical Bearing Capacity

The DPA-combi screw piles are inserted to the calculated drilling depth during soundings. The required drilling torque is measured to assess and recognize the existing soil strata.

Post-Production (Optional)

Through our own quality control, we can respond adequately to doubts about the pile quality or to client requests regarding the execution.

DPA-combi screw piles manufactured by Vroom Funderingstechnieken can be acoustically measured and subsequently assessed by an independent consultancy firm.

Get Advice

Vroom Funderingstechnieken takes the utmost care in the creation of our brochures and website. However, no rights can be derived from the content. If you use information from our brochures or 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 your intended application. For questions regarding the application of our products for specific projects, we recommend contacting our sales department.

DPA-combi screw piles
DPA-combi screw piles
DPA-combi screw piles
DPA-combi screw piles

Characteristics

  • Displaces soil, with only limited emerging drilling soil at the drill pipe and ground level.
  • Low vibration, making it suitable for use near buildings that are sensitive to damage from settlements and/or vibrations.
  • Noise-friendly, resulting in less disturbance to the surrounding area, and suitable for use near homes, schools, public buildings, etc.
  • Pile head is suspended below the working level.
  • Pile length can be directly adjusted to the soil conditions.
  • Adjustments in pile specifications are possible up to the ordering moment of prefab elements.
  • Batter piles available upon request and depending on the situation and pile length.
  • Can be loaded both in tension and compression.
  • Prestressed reinforcement over the entire length.
  • The pile system is known and accepted by the Building and Housing Supervision service and engineers, as well as in Building Standards. Competitive compared to soil-removing and grout-injected piles due to soil-displacing execution, required bearing capacity, and a 'clean' construction site.

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

Quality Control

Vroom Funderingstechnieken manufactures DPA-combi screw piles according to an implementation procedure drawn up for Vroom Funderingstechnieken within the framework of internal quality control, national standards, and execution conditions.
The grout is sourced from certified concrete plants. The prefab concrete elements are produced and supplied by certified manufacturers.

Verification of Geotechnical Bearing Capacity

The DPA-combi screw piles are inserted to the calculated drilling depth during soundings. The required drilling torque is measured to assess and recognize the existing soil strata.

Post-Production (Optional)

Through our own quality control, we can respond adequately to doubts about the pile quality or to client requests regarding the execution.

DPA-combi screw piles manufactured by Vroom Funderingstechnieken can be acoustically measured and subsequently assessed by an independent consultancy firm.

Get Advice

Vroom Funderingstechnieken takes the utmost care in the creation of our brochures and website. However, no rights can be derived from the content. If you use information from our brochures or 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 your intended application. For questions regarding the application of our products for specific projects, we recommend contacting our sales department.

Technical data

General

  • Batter piles available upon request and depending on the situation and pile length.
  • Available auxiliary equipment: concrete pump, shovel, and bucket.
  • Machine noise level approximately 90 dB. The system can be considered vibration-free.

Drilling Equipment

Continuously adjustable and dependent on the drilling motor:

  • Torque 250 to 500 kNm.
  • Pull down 150 to 400 kN.

Grout

Grout strength 25 to 35 N/mm². Grout is introduced with a bucket or a concrete pump and is not pressurized. The pressure in the auxiliary tube is the static occurring pressure. During execution, a calculated amount of grout is introduced, and the screw tube is further filled with water.

Prefabricated Concrete Element

The prefabricated concrete element is equipped with a lifting provision in the pile head and is chamfered on all four sides. The prefab concrete core can be factory-fitted with profiling or an embedded dowel anchor.

Bearing Capacity

Geotechnical bearing capacity according to Eurocode 7 (NEN 6743).
The screw point is a cast point constructed with driving lugs on the outside of the shaft dimension. The ratio of foot plate to shaft is optimized so that the pile shaft has the same diameter as the pile point.
The bearing capacity factors to be maintained according to Eurocode 7 (NEN 6743), with the pile point level considered as the bottom of the screw tube.

Pile Point Bearing Factor

αp = 0.63
β = 1.0 (Dfoot = Dshaft)
S = 1.0

Shaft Friction Factor

Shaft friction for compression piles
αs = 0.009 (over the outer diameter of the pile)
Shaft friction for tension piles
αt = 0.009 (over the outer diameter of the pile)

Load and Deformation Behaviour

According to Eurocode 7 (NEN 6743, type 1, figures 6 and 7)

Loading Spectrum

Depending on the diameter and soil conditions up to approximately 3000 kN compression and 500 kN tension (calculated value)
In specific projects, higher loads are possible in consultation with a geotechnical advisor and Vroom Funderingstechnieken.

Constructive Aspects

Available screw tube diameters, shaft point diameter, in mm:

  • Square 250 mm 410/460 mm
  • Square 290 mm or octagonal 315 mm 460/510 mm
  • Square 320 mm or octagonal 365 mm 510/560 mm

Other diameters available on request. Maximum pile length is approximately 35 meters, depending on the diameter and soil conditions. Longer pile lengths are examined upon request.

Manufacturing

 

  1. Positioning of the steel auxiliary tube, equipped with a loose, closing screw point. Drill head and drill point are positioned correctly at ground level.
  2. Hydraulic drilling equipment, combined with the pull down force, screws the auxiliary tube to the desired depth.
  3. The prefabricated concrete element is introduced when the auxiliary tube has reached the required depth.
  4. Grout mixture is poured into the auxiliary tube using a bucket.
  5. The auxiliary tube is unscrewed, leaving the screw point and the prefabricated element, surrounded by grout, in place.
  6. Pile ready, move the machine to the next position.

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