EP4273327A1

EP4273327A1 - A method for providing a concrete pile and a concrete pile

Info

Publication number: EP4273327A1
Application number: EP23171385.0A
Authority: EP
Inventors: Martien Willem KOOL; Johannes Maria Veenman
Original assignee: Hpschroefpaal Beheer BV
Current assignee: Hpschroefpaal Beheer BV
Priority date: 2022-05-05
Filing date: 2023-05-03
Publication date: 2023-11-08
Also published as: NL2031784B1

Abstract

A method for providing a reinforced hollow concrete pile (250) for pile driving, the method comprises the steps of:
- providing a concrete beam (150) having a hollow core,
- removing a portion of concrete (151) from a pile head section and/or a pile bottom section of the concrete beam to expose the hollow core,
- placing a reinforcement (200) in the hollow core of the pile head section and/or the pile bottom section,
- filling the pile head section and/or the pile bottom section with a concrete mixture (154),
- allowing the concrete to set to yield the reinforced hollow concrete pile for pile driving.

Description

The present invention relates to a method for providing a reinforced hollow concrete pile for pile driving.
Concrete piles are used as part of a foundation in order to be able to build a building on ground that is for example soft or wet. The foundation provides support for the building on the ground and transfers loads of the building to the ground.
It is known to use piles comprising a hollow middle section as opposed to piles of solid concrete.
However, a disadvantage of these sections is that they are not suitable for introduction into the ground by pile driving since they are not able to withstand an impact of a hammer head.
It is an object of the present invention to provide a concrete pile that is suitable for pile driving and which is relatively cheap to produce and/or easy to handle.
To this end, a method according to the preamble is characterized in that the method comprises the steps of:
providing a concrete beam having a hollow core,

removing a portion of concrete from a pile head section and/or a pile bottom section of the concrete beam,
placing a reinforcement in the pile head section and/or the pile bottom section,
filling the pile head section and/or the pile bottom section with a concrete mixture,
allowing the concrete to set to yield the reinforced hollow concrete pile for pile driving.

In this way a pile is provided which is cheaper to produce while being suitable for pile driving. A volume of the hollow core is for example 20 or 30% of a total volume of the pile, thus saving concrete, weight and costs.
The concrete mixture comprises water, sand and cement in such proportions that the hollow concrete pile does not collapse.
Removing a portion of concrete from a pile head section and/or the pile bottom section can be removing concrete from a side of the beam in the pile head section and/or bottom head section, thereby exposing the hollow core of the beam. It can also be removing all concrete from the pile head section and/or pile bottom section of the beam.
According to an embodiment, the concrete pile having a hollow core is provided by a wet casting method, a slip forming method or an extrusion method.
According to an embodiment, the concrete pile having a hollow core is provided by an extrusion method.
GB 994578 describes such an extrusion method for providing reinforced hollow concrete sections.
According to an embodiment, the concrete pile having a hollow core comprises rebars or tendon wires extending in a longitudinal direction of the pile.
The rebars or tendon wires provide the concrete pile with additional strength, so the piler may better withstand the impact of a hammer head during pile driving. When rebars or tendon wires are present, the reinforcement can be placed such that the rebars or tendon wires are located within a circumference of the reinforcement, or such that the rebars or tendon wires are located outside the circumference of the reinforcement.
According to an embodiment, the second concrete mixture is compacted after filling the pile head section and/or the pile bottom section with a second concrete mixture.
Compacting the second concrete mixture results in a stronger piler head and/or bottom, so the piler may better withstand the impact of a hammer head during pile driving. Compacting may for example be performed by shaking or vibration.
According to an embodiment, setting of the first concrete mixture and the second concrete mixture is facilitated by heating.
Heating the first and second concrete mixtures assists in accelerating setting of the concrete mixtures, so the piler may be produced faster. The heating is for example provided by a heating conduit extending along the setting piler.
According to an embodiment, the reinforcement comprises a metal helix.
A helix is easily introduced in the hollow core or wrapped around tendion wires, and a pitch of the helix may be adapted to a desired number to provide the required reinforcement. The helix of the pile head section may for example comprise 3-12 windings having a pitch of 1-10 cm. Preferably, the helix comprises 5-9 windings having a pitch of 4-5 cm.
According to an embodiment, after the step of allowing the first concrete mixture and the second concrete mixture to set, the reinforced hollow concrete beam is cut transversally at the level of the pile head section and/or pile bottom section.
In this way multiple reinforced hollow concrete piles may be produced in a single run.
According to an embodiment, the reinforced concrete pile is cut transversely at the level of the pile head section and/or pile bottom section such that mutiple reinforced hollow concrete piles are obtained from one concrete beam.
Finally, the present invention relates to a reinforced hollow concrete pile for pile driving,, wherein the pile extends in a first direction and comprises

a pile head section,
a pile bottom section, and
a hollow core extending in the first direction between the pile head section and the pile bottom section,

According to an embodiment, the concrete pile having a hollow core comprises rebars or tendon wires extending in a longitudinal direction of the pile.
The rebars or tendon wires provide the concrete pile with additional strength, so the piler may better withstand the impact of a hammer head during pile driving. When rebars or tendon wires are present, the reinforcement can be placed such that the rebars or tendon wires are located within a circumference of the reinforcement, or such that the rebars or tendon wires are located outside the circumference of the reinforcement.
According to an embodiment, the reinforcement is in the form of a metal spiral.
A spiral is easily introduced in the hollow core or wrapped around tendon wires, and a pitch of the spiral may be adapted to a desired number to provide the required reinforcement. The helix of the pile head section may for example comprise 3-12 windings having a pitch of 1-10 cm. Preferably, the helix comprises 5-9 windings having a pitch of 4-5 cm.
According to an embodiment, the pile head section extends over a length of 30-100 cm, preferably over a length of 40-70 cm, such as 60 cm.
According to an embodiment, the pile bottom section extends over a length of 10-50 cm, preferably over a length of 20-40 cm, such as 30 cm.
According to an embodiment, a diameter of the hollow core is 40-70% of a width of the reinforced hollow concrete pile, preferably 50-60%.
The present invention will now be illustrated with reference to the drawing where

Fig. 1A-1D show a process of providing a reinforced hollow pile according to an embodiment of the invention;
Fig. 2A shows a longitudinal cross section of a reinforced hollow pile;
Fig. 2B shows a cross section B-B of the reinforced hollow pile at a level of a middle section; and
Fig. 2C shows a cross section C-C of the reinforced hollow pile at a level of a middle section.

Fig. 1A shows a cross sectional view of a multitude of tendon wires 100 that extend in a longitudinal direction. The tendon wires 100 are provided above a supporting surface 110, under which heating conduits 120 extend. In this embodiment, the tendon wires 100 are arranged in sets of four tendon wires 100, such that of each set a first and a second tendon wire 100 are provided in a first plane substantially parallel to the supporting surface, and a third and a fourth tendon wire 100 are provided in a second plane substantially parallel to the supporting surface 110. Of each set of tendon wires 100 the first and the third tendon wire 100 are provided in a third plane substantially perpendicular to the supporting surface 110, and the second and the fourth tendon wire 100 in a fourth plane substantially perpendicular to the supporting surface 110.
Fig. 1B shows a cross section of the bottom part of a device 130 for providing a first concrete mixture 153. In this embodiment, the device 130 is an concrete extruder 130 provided with wheels 131 which enable the extruder 130 to drive in the longitudinal direction over the support surface 110 while extruding concrete. In this embodiment the extruder 130 comprises four screws 132. The extruder 130 is aligned such that each screw 132 is positioned substantially centered with respect to the four tendon wires 100 of each set of tendon wires 100. The first concrete mixture 153 is extruded by means of four sets of dies and mandrels which are shaped to produce the required cross section as shown in Fig. 1C. The four tendon wires 100 of a set of tendon wires 100 are embedded in the first concrete mixture. The extruder is furthermore provided with guiding surfaces 140 which are aligned with the upright side walls of the dies, that guide the first concrete mixture being extruded and assist in shaping a concrete profiled hollow beam 150 having a hollow core 151 as shown in Fig. 1C.
Fig. 1D shows a cross section of the concrete hollow beam 150 having a hollow core 151 at the level of a pile head and bottom section 152. A portion of concrete in the upper wall of the beam is removed from one or more pile head/bottom sections, such that the hollow core 151 of the concrete hollow beam 150 is exposed. One or more reinforcements 200 are then placed in the hollow core 151, and the hollow core 151 and the space of the removed wall part of the pile head/bottom section 152 is filled with a second concrete mixture 154, as shown in Figs. 2A and 2C. The concrete beam 150 is then heated by means of the heating conduits 120 and allowed to set to yield the reinforced hollow concrete beam 150. The beam 150 is then cut through at the locations of the reinforcement 200 in the pile head/bottom section(s), whereby multiple hollow reinforced piles are obtained having a reinforced head and a reinforced bottom.
Fig. 2A shows a longitudinal cross section of an end part of the finished reinforced hollow concrete pile 250 for pile driving.
Fig. 2B shows a cross section A-A of the reinforced hollow concrete pile 250 for pile driving at the level of a middle section between the pile head section 152 and a pile bottom section.
Fig. 2C shows a cross section C-C of the reinforced hollow concrete pile 250 for pile driving at the level of the pile head.
The pile head section 152 comprises the reinforcement 200 which extends in the longitudinal direction of the concrete pile 250 and which in this embodiment is in the form of a reinforcing metal helical wire 201 which is fixed in shape by means of wires 202 extending in the axial direction of the helix, and which are fixed to the helical wire 201. The hollow core 151 is filled with the second concrete mixture 154, resulting in the reinforcing metal helix 200 being embedded in the concrete mixture. The middle section comprises the hollow core 151 extending between the pile head section 152 and the pile bottom section 152.

Claims

A method for providing a reinforced hollow concrete pile for pile driving, wherein the method comprises the steps of:
providing a concrete beam having a hollow core,
- removing a portion of concrete from a pile head section and/or a pile bottom section of the concrete beam,

- placing a reinforcement in the pile head section and/or the pile bottom section,

- filling the pile head section and/or the pile bottom section with a concrete mixture,

- allowing the concrete to set to yield the reinforced hollow concrete pile for pile driving.
The method according to claim 1, wherein the concrete pile having a hollow core is provided by a wet casting method, a slip forming method or an extrusion method.
The method according to claim 2, wherein the concrete pile having a hollow core is provided by an extrusion method.
The method according to any of the preceding claims, wherein the concrete pile having a hollow core comprises rebars or tendon wires extending in a longitudinal direction of the pile.
The method according to any of the preceding claims, wherein the second concrete mixture is compacted after filling the pile head section and/or the pile bottom section with a second concrete mixture.
The method according to any of the preceding claims, wherein setting of the first concrete mixture and the second concrete mixture is facilitated by heating.
The method according to any of the preceding claims, wherein the reinforcement comprises a metal helix.
The method according to any of the preceding claims, wherein after the step of allowing the first concrete mixture and the second concrete mixture to set, the reinforced hollow concrete beam is cut transversally at the level of the pile head section and/or pile bottom section.
The method according to claim 8, wherein the reinforced concrete pile is cut transversely at the level of the pile head section and/or pile bottom section such that mutiple reinforced hollow concrete piles are obtained from one concrete beam.
A reinforced hollow concrete pile for pile driving,, wherein the pile extends in a first direction and comprises
- a pile head section,

- a pile bottom section, and

- a hollow core extending in the first direction between the pile head section and the pile bottom section,
wherein the pile head section and/or the pile bottom section comprises a reinforcement embedded in a concrete mixture.
The concrete pile according to claim 10, wherein the concrete pile having a hollow core comprises rebars or tendon wires extending in a longitudinal direction of the pile.
The concrete pile according to any of the claims 10 or 11, wherein the reinforcement is in the form of a metal spiral.
The concrete pile according to any of the claims 10 to 12, wherein the pile head section extends over a length of 30-100 cm, preferably over a length of 40-70 cm, such as 60 cm.
The concrete pile according to any of the claims 10 to 13, wherein the pile bottom section extends over a length of 10-50 cm, preferably over a length of 20-40 cm, such as 30 cm.
The concrete pile according to any of the claims 10 to 14, wherein a diameter of the hollow core is 40-70% of a width of the reinforced hollow concrete pile, preferably 50-60%.