Method and formwork envelope for covering foundation piles

Abstract

A method for capping foundation piles, in which an upper end of a concrete foundation pile with an internal reinforcement cage is exposed and the concrete part of the foundation pile is cut off from a part of the foundation pile projecting into the ground above the level of a planned foundation base, is provided that the reinforcement cage in the area of ​​the foundation pile that projects above the level of the planned foundation base is lined at least partially with at least one formwork shell before concreting.

Description

[0001] The invention relates to a method and a formwork shell for capping foundation piles, in which an upper end of a concreted foundation pile with an internal reinforcement cage is exposed and the concrete part of the foundation pile above the level of a planned foundation base is separated from a part of the foundation pile projecting into the ground.

[0002] Foundation piles are used to transfer high loads into deeper, more stable soil layers. They are often made of cast-in-place concrete, with various methods being used to place the concrete and reinforcement cage. What these methods have in common is that the concreted foundation piles initially extend above the level of the planned foundation base of a structure to be constructed on the foundation base. The reason for this "over-concreting" of the foundation piles, i.e., beyond the foundation base, arises from the specific concreting method. To counteract segregation of the freshly placed concrete, a concrete supply pipe always extends into the fresh concrete during filling and ends below the fresh concrete surface. Due to segregation and inclusions, less stable concrete floats to the top and must be removed again after the concrete of the foundation pile has set.

[0003] This cutting is usually done manually and is physically demanding due to, among other things, strong whole-body and hand-arm vibrations, dust generation, and high levels of noise. While this strain can be reduced with a special chiseling technique, the work is still physically demanding. Special machines are intended to remedy this, but their design has disadvantages that limit their use.

[0004] One of these specialized machines is a pile breaker. However, if used improperly and on sites designed for this system, pile breakers can easily cause damage to the reinforcement cage. They also require large equipment weighing more than 20 tons and appropriate access routes for handling.

[0005] Pile head cutters can also only be used in combination with large equipment. Another challenge with cutters is the particularly high dust generation, which requires a corresponding irrigation system, as much of the resulting highly alkaline concrete dust still escapes into the environment. Finally, the foundation piles can also be removed using mini excavators. Although mini excavators can be used much more flexibly due to their smaller dimensions and weight of less than 2.8 t, they are more difficult to control than hand-held devices and can therefore quickly cause microcracks in the foundation pile.

[0006] The object of the invention is therefore to provide a method and a device which optimises the cutting of foundation piles in such a way that the process is more cost-effective and flexible and occupational safety is increased.

[0007] This problem is solved in terms of method with the features of claim 1 and in terms of device with the features of claim 7. Further developments and advantageous embodiments are specified in the respective subordinate claims.

[0008] The method for capping foundation piles, in which an upper end of a concreted foundation pile with an internal reinforcement cage is exposed and the concrete part of the foundation pile above the level of a planned foundation base is separated from a part of the foundation pile projecting into the ground, is characterized according to the invention in that the reinforcement cage in the area of ​​the foundation pile that projects above the level of the planned foundation base is covered at least in sections with at least one formwork shell before concreting.

[0009] The formwork shell then forms a separating layer between the reinforcement cage and the freshly poured concrete, preventing the fresh concrete and reinforcement cage from bonding together in the concrete portion of the foundation pile above the level of the planned foundation base. Without the bond to the reinforcement, the hardened concrete can then be separated from the portion of the foundation pile protruding into the ground much more easily and with less effort.

[0010] In order to achieve a separation edge between the concrete part of the foundation pile above the level of a planned foundation base and the part of the foundation pile projecting into the ground, which is as level as possible with the level of the planned foundation base, a further development provides for a concrete casing of the foundation pile surrounding the reinforcement cage to be cut at the level of the planned foundation base after the concrete has set. This cut then ensures that, when the concrete part above the level of a planned foundation base is subsequently cut, any concrete parts that break out only affect the concrete part to be cut off. The cut is preferably carried out in accordance with DIN EN 1536 or ZTV-ING Part 2 Foundation Engineering Section 2 Foundations, so that the reinforcement cage remains in place.

[0011] Subsequently, according to a further development, at least two boreholes are drilled into the concrete shell of the concrete part to be separated, in particular in an area close to the level of the planned foundation base. "Close to the level of the planned foundation base" means a distance from the incision of a few centimeters up to at least one lower third of the concrete part to be separated, adjacent to the incision. In particular, these boreholes are distributed evenly along the circumference or in a row one above the other, whereby in a row one above the other, the boreholes can be arranged at equal distances from one another along the longitudinal axis of the foundation pile.In a further embodiment, these bores have a diameter of between 30 mm and 80 mm, in particular between 45 mm and 55 mm, and a depth of between 15 cm and 55 cm, in particular between 25 cm and 45 cm, in particular exactly 35 cm.

[0012] In a next process step, at least one splitting tool is advantageously inserted into the boreholes, with which an essentially radial fracture plane is created in the foundation pile at the level of the planned foundation base. Since there is no connection between the reinforcement cage and the concrete to be separated above the level of the foundation base due to the previously placed formwork shell(s), the over-concreted concrete section above the level of the foundation base can now be easily removed. A crane, for example, can be used for this purpose, so that no large equipment is required in the immediate vicinity of the foundation pile. The remaining work then only involves leveling a small stump up to 10 cm above the cut.However, these remaining works cannot be avoided even with the state-of-the-art methods for cutting foundation piles and are usually more extensive.

[0013] After the formwork shell(s) have been removed, the portion of the reinforcement cage that extends above the foundation level forms the connecting reinforcement for the structure to be erected. If necessary, a spacer ring at the end of the reinforcement cage must also be removed.

[0014] To avoid impeding the concreting process, a further development provides for a formwork shell to be assigned to each bar or reinforcing bar of the reinforcement cage. The existing methods for pouring concrete can thus be easily applied and integrated into the new method. Furthermore, it is ensured that a concrete core located within the reinforcement cage is sufficiently connected to the concrete shell to allow the concrete section to be separated, consisting of the concrete shell and concrete core, to be completely broken open and removed. The formwork shells can be formed relatively simply from pipe segments.

[0015] By sealing the gaps between the bars of the reinforcement cage and the formwork shells at the upper and lower ends of the formwork shells, in particular by sealing them with adhesive tape, a further development has shown that fresh concrete cannot penetrate into the gaps.

[0016] The invention further relates to a formwork shell for capping foundation piles. This is characterized according to the invention in that each formwork shell is formed from two half-pipe segments having interlocking connecting means, that the connecting means of the half-pipe segments are formed on their radially opposite longitudinal edges, and that the two half-pipe segments, with their common inner diameter, are adapted in particular to a bar of a reinforcement cage that is intended to be enclosed. Because the formwork shell is formed from half-pipe segments, it can be mounted particularly easily on bars of a reinforcement cage, particularly when the cage has a spacer ring or the like at the end, which prevents the formwork shells from being pushed onto the bars.

[0017] According to the invention, the inner diameter is adapted to the diameter of the bars or reinforcing bars, which can vary depending on the foundation pile and the expected loads. Adapted to the bars or reinforcing bars therefore means slightly, i.e. an inner diameter of the formwork shell that is a few millimeters larger than the diameter of the bars, in particular an inner diameter of the formwork shell that is less than 20% of the diameter of the bar larger, in particular an inner diameter of the formwork shell that is less than 10% of the diameter of the bar larger, in particular an inner diameter of the formwork shell that is up to 6 mm larger than the diameter of the bar, in particular an inner diameter of the formwork shell that is up to 4 mm larger than the diameter of the bar.

[0018] The connecting means of the half-pipe segments are formed on their radially opposite longitudinal edges, so that the two half-pipe segments can be connected to one another along their entire longitudinal extent. In a further embodiment, each of the half-pipe segments has at least one locking lug and at least one locking hook corresponding to the locking lug as connecting means. The locking lug and locking hook are advantageously designed such that the half-pipe segments can be placed on both sides of the bar of the reinforcement cage and locked together by pressing them together, enclosing the bar.

[0019] Easier handling of the half-pipe segments and formwork elements is also achieved by ensuring that the half-pipe segments of a formwork shell are identical to each other. Identical half-pipe segments of the same size that together form a formwork shell can be freely combined with each other, thus enabling, among other things, reduced inventory at companies and on construction sites. Furthermore, there is no need to match two matching half-pipe segments, as all half-pipe segments of the same size and length can always be connected together.

[0020] According to the invention, the identical shape of the half-pipe segments can be achieved by assigning the at least one locking lug to a first of the longitudinal edges of the half-pipe segment and the at least one locking hook to a second of the longitudinal edges of the half-pipe segment. Two identical half-pipe segments then only need to be rotated 180° relative to each other around their longitudinal axes to be able to press them together with their longitudinal edges and lock them into place.

[0021] In order to ensure a uniform connection of the half-pipe segments over the entire length of the formwork shell, a further development provides that the locking lug and the locking hook each extend over the entire length of the longitudinal edge of the half-pipe segment.

[0022] In a further embodiment, the locking lug is formed by a bead-like widening of the longitudinal edge, wherein the bead-like widening tapers from a contact section for a corresponding half-pipe segment of the formwork shell, in particular an outer circumference of the contact section facing the corresponding half-pipe segment, in the direction of a projection which, pointing away from the corresponding half-pipe segment, forms an undercut for the locking hook of the corresponding half-pipe segment. The taper of the bead-like widening of one half-pipe segment, in addition to the undercut of the connecting means formed between the two half-pipe segments, clamps the two half-pipe segments together. As a result, the two half-pipe segments can then be connected to one another even if the locking lug or locking hook is at least partially broken off.

[0023] According to a further development, the locking hook is formed on the longitudinal edge associated with the locking hook by a part projecting from a contact section for a corresponding half-pipe segment. The part tapers toward a projection of the locking lug with an inner surface that engages the locking lug of the corresponding half-pipe segment, and has a locking end that can be brought into engagement with the projection by undercutting it. This provides the largest possible connection surface between the section tapering toward the projection and the inner surface of the locking hook, thus ensuring a particularly secure hold.

[0024] In order to be able to connect the locking hook and the locking lug to one another easily and with less force, a further development provides for the locking hook and the locking lug to have rounded surfaces in the areas where two half-pipe segments are guided past one another to connect them. When the half-pipe segments are pressed together, increasing force must be applied until they click into place, whereby the more force required, the more precise guidance of the half-pipe segments sliding onto one another is provided. In a further embodiment, the rounded surfaces are then formed on the outside of the locking lug and on the outside and inside of the locking hook, in particular on the outside of the locking end bent over to form the projecting part.

[0025] An embodiment of the invention, from which further essential features of the invention may emerge, is illustrated in the drawing. Identical parts are provided with the same reference numerals throughout the figures of the drawing. They show: Figure 1: a cross-section through a formwork shell according to the invention; Figure 2: a section of a bar of a reinforcement cage with a formwork shell placed above the level of a planned foundation base according to Fig. 1 in perspective detailed view; Figure 3: a perspective view of a foundation pile partially exposed after concreting; Figure 4: a perspective view of the partially exposed foundation pile according to Fig. 3 , in which a concrete part of the foundation pile was cut above the level of a planned foundation base.

[0026] From the cross-section of the Figure 1It can be seen that a formwork shell 1 according to the invention is formed from two identical half-pipe segments 2, 2'. These half-pipe segments 2, 2' are rotated by 180° to one another along their longitudinal axes and each abut against one another with contact sections on their longitudinal edges 3a, 3b, 3a', 3b'. The half-pipe segment 2 has the longitudinal edges 3a, 3b and the half-pipe segment 2' has the longitudinal edges 3a', 3b'. The longitudinal edge 3a abuts the longitudinal edge 3b', forming a pair, and the longitudinal edge 3b abuts the longitudinal edge 3a', forming a pair. A locking lug 4, 4' is formed on each of the longitudinal edges 3a, 3a'. The longitudinal edges 3a, 3a' with the locking lugs 4, 4' are each widened in a bead-like manner, wherein the bead-like widening tapers from an outer circumference of the contact section of the longitudinal edge 3a, 3a' in the direction of a projection 5, 5'.The projections 5, 5' form an undercut pointing away from the respective corresponding half-pipe segment 2, 2' for a locking hook 6, 6' formed on the longitudinal edges 3b, 3b' of the corresponding half-pipe segment 2, 2'.

[0027] The locking hooks 6, 6' each have a part 7, 7' projecting in the direction of the corresponding half-pipe segment 2, 2', the inner surface 7a, 7a' of which rests against the tapered region of the corresponding locking lug 4, 4'. At its end, the projecting part 7, 7' is bent in the direction of the contact section of the longitudinal edge 3b, 3b', from whose outer circumference it extends, encompassing the locking lug 4, 4', in the direction of the corresponding half-pipe segment 2, 2'. The ends bent in the direction of the contact section of the longitudinal edge 3b, 3b' form locking ends 8, 8', which engage behind the respectively associated projection 5, 5' and thus position the two half-pipe segments 2, 2' in a predetermined manner relative to one another and press them together.

[0028] Figure 2shows the formwork shell 1 attached to a bar 9 of a reinforcement cage, with the formwork shell 1 extending over the entire length of the reinforcement cage located above the level of a planned foundation base. This part of the reinforcement cage above the level of a planned foundation base will then form connecting reinforcement for a structure to be constructed after the completion of a corresponding foundation pile. To prevent the penetration of fresh concrete between bar 9 and the formwork shell 1, the ends of the formwork shell 1 are sealed with adhesive tape 10.

[0029] Out of Figure 3A concrete foundation pile 11 is visible, the concrete section 12 of which, located above the level of a planned foundation base, has been exposed. At the level of the planned foundation base, the foundation pile 11 has a notch 13 in its concrete casing surrounding an internal reinforcement cage. This notch 13 separates the concrete section 12 to be capped from a part of the foundation pile 11 that is to be retained. Above the notch 13, bores 14 are drilled into the concrete casing of the concrete section 12, into which a splitting tool is inserted, with which an essentially radial fracture plane is created in the foundation pile 11 at the level of the planned foundation base.

[0030] In Figure 4 Finally, the capped foundation pile 11 with the remaining connecting reinforcement 15 of the reinforcement cage is shown before part of the formwork shells 1 have been removed from the bars 9.

Claims

1. A method for cutting foundation piles (11), in which an upper end of a concreted foundation pile (11) with an internal reinforcement cage is exposed and the concrete part (12) of the foundation pile (11) above the level of a planned foundation base is separated from a part of the foundation pile (11) projecting into the ground, characterized by that the reinforcement cage in the area of ​​the foundation pile (11) which projects above the level of the planned foundation base is covered at least in sections with at least one formwork shell (1) before concreting.

2. Method according to claim 1, characterized in that a concrete casing of the foundation pile (11) surrounding the reinforcement cage is cut into the level of the planned foundation base after the concrete has set.

3. Method according to one of claims 1 or 2, characterized in thatat least two bores (14) are made in the concrete shell of the concrete part (12) to be separated, in particular in an area close to the level of the planned foundation base.

4. Method according to claim 3, characterized in that at least one splitting tool is inserted into the bores (14), with which a substantially radial fracture plane is produced in the foundation pile (11) at the level of the planned foundation base.

5. Method according to one of claims 1 to 4, characterized in that each bar (9) of the reinforcement cage is assigned a formwork shell (1).

6. Method according to claim 5, characterized in that Gaps between the bars (9) of the reinforcement cage and the formwork shells (1) at the upper and lower ends of the formwork shells (1) are closed, in particular with adhesive tape (10).

7. Formwork shell (1) for capping foundation piles (11), characterized by thateach formwork shell (1) is formed from two half-pipe segments (2, 2') which have interlocking connecting means, that the connecting means of the half-pipe segments (2, 2`) are formed on their radially opposite longitudinal edges (3a, 3a`, 3b, 3b`) and that the two half-pipe segments (2, 2') with their common inner diameter are adapted in particular to a bar (9) of a reinforcement cage which is intended to be enclosed.

8. Formwork shell (1) according to claim 7, characterized in that each of the half-pipe segments (2, 2') has, as connecting means, at least one locking lug (4, 4') and at least one locking hook (6, 6') corresponding to the locking lug (4, 4').

9. Formwork shell (1) according to one of claims 7 or 8, characterized in that the half-pipe segments (2, 2`) of a formwork shell (1) are identical to one another.

10. Formwork shell (1) according to claim 8, characterized in thatthe at least one locking lug (4, 4`) is assigned to a first of the longitudinal edges (3a, 3a`) of the half-pipe segment (2, 2`) and the at least one locking hook (6, 6`) is assigned to a second of the longitudinal edges (3b, 3b`) of the half-pipe segment (2, 2`).

11. Formwork shell (1) according to one of claims 8 or 10, characterized in that the locking lug (4, 4') and the locking hook (6, 6`) each extend over the entire length of the longitudinal edge (3a, 3a`, 3b, 3b`) of the half-pipe segment (2, 2`).

12. Formwork shell (1) according to one of claims 8, 10 or 11, characterized in thatthe locking lug (4, 4') is formed by a bead-like widening of the longitudinal edge (3a, 3a`), wherein the bead-like widening tapers from a contact section for a corresponding half-pipe segment (2, 2`) of the formwork shell (1), in particular an outer circumference of the contact section facing the corresponding half-pipe segment (2, 2`), in the direction of a projection (5, 5`) which, pointing away from the corresponding half-pipe segment (2, 2`), forms an undercut for the locking hook (6, 6`) of the corresponding half-pipe segment (2, 2`).

13. Formwork shell (1) according to one of claims 8 or 10 to 12, characterized in thatthe locking hook (6, 6`) is formed on the longitudinal edge (3b, 3b') assigned to the locking hook (6, 6`) by a part (7, 7`) which projects relative to a contact section for a corresponding half-pipe segment (2, 2`), which part tapers in the direction of a projection (5, 5`) of the locking lug (4, 4`) with an inner surface (7a, 7a`) which is brought into contact with the locking lug (4, 4`) of the corresponding half-pipe segment (2, 2`) and has a locking end (8, 8`) which can be brought into engagement with the projection (5, 5`) in an undercutting manner.

14. Formwork shell (1) according to one of claims 8 or 10 to 13, characterized in that the locking hook (6, 6') and the locking lug (4, 4') have rounded surfaces in areas which are to be guided past one another in order to connect two half-pipe segments (2, 2').

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