DE102009039570B4 - Reinforcement for a foundation element and method for creating the foundation element and foundation element - Google Patents

Abstract

Reinforcement for a foundation element (5) in the floor (3) comprising metal bars (12) interconnected to form a reinforcing cage (14) having a biasing means disposed at the foot thereof, at least one lead (32) and at least one Discharge (34) for supplying or discharging a fluid to the biasing means are provided and extend to an upper portion of the reinforcing basket (14), characterized in that the biasing means comprises an expandable sheet metal hollow body (30), which via holders (20) on the Reinforcing cage (14) is fixed, that the holders (20) have a lower rigidity than the metal rods (12), wherein the sheet hollow body (30) in total on the holder (20) upon inflation movable to the metal bars (12) of the reinforcing basket (14 ), and that the supply line (32) and the discharge line (34) are fixed to the reinforcement cage (14).

Description

The invention relates to a reinforcement for a foundation element in the ground, which has metal rods which are interconnected to form a reinforcing cage, according to the preamble of claim 1.

Furthermore, the invention relates to a method for creating a foundation element in the ground, wherein initially a recess is created in the ground, in which a reinforcement used and which is filled with a curable filling compound according to claim 11, and a foundation element according to claim 10.

Such foundation elements are used for the removal of larger vertical forces of a building in the ground. The foundation elements can be created by drilling as piles or by trench wall trenching or diaphragm wall grabs as trench wall fins. The created recess is filled to form the foundation element with a curable filling compound, usually a concrete or cement paste, wherein a reinforcement of metal rods is used to increase the strength.

To increase the carrying capacity, it is known to bias the foundation element by appropriate means. From the DE 10 2006 007 144 A1 For example, a Pfahlhubkissen is known, which can be arranged in a foundation pile and volume expanded by introducing a pressure fluid. In this way, a lower part of the pile can be braced against a Pfahloberteil. By this applied bias the skin friction is activated, so that overall larger load capacities can be absorbed. In addition, subsidence of the building bottom can be anticipated by such biasing devices, so that the structure can be erected on such biased foundation elements with increased security against subsidence. Another biasing device goes out of the GB 589,019 out.

The arrangement of these biasing devices is complex and in particular requires time for exact positioning and adjustment.

Further, it is known to arrange so-called load cells in the foundation elements, with which directly the carrying capacity of the foundation element can be determined, such as from the DE 34 24 776 A1 , of the EP 1 930 506 B1 or the GB 2 159 961 A is known.

From the DE 34 07 938 A1 For example, a method and apparatus for testing and solidifying the foundation of bored piles is known. Here, a complex press is used, which consists of metal and reinforced concrete and has a press head made of metal with inlets and outlets for grout and a presser foot in the form of a piston made of concrete.

The DE 874 125 B describes a hydraulic pressure generator, which consists of a flat container made of sheet metal. This is to be used in particular in construction technology.

In the DE 2 015 687 A is a structure described in the soil, in which a particularly high load capacity in vertical and oblique directions is possible.

The invention has for its object to provide a reinforcement for a foundation element, a method for creating a foundation element and a foundation element with which highly efficient high-carrying foundation elements in the ground can be produced.

The object is achieved on the one hand by a reinforcement with the features of claim 1 and on the other hand with a method having the features of the method claim 11. Preferred embodiments of the invention are specified in the respective dependent claims.

The reinforcement according to the invention is characterized in that in a foot region of the reinforcing basket an expandable sheet metal hollow body is fastened via holders to the movement basket and that at least one supply line and at least one discharge line for supplying or discharging a fluid are provided in the hollow sheet metal body, wherein the supply line and the drain are attached to the reinforcement cage and extend to an upper region of the reinforcement cage.

A basic idea of the invention can be seen in forming the elements of the reinforcing cage and the pretensioning device as one unit. The elements of the reinforcement cage consist essentially of longitudinal bars, a spiraling spiral, stiffening rings and a ring tension reinforcement. The formation of a unit, the effort to introduce the biasing device can be considerably simplified, since the reinforcing cage is stable and easy to handle from the metal elements. In this case, the lines for the biasing device are arranged on the reinforcement cage. With the introduction of the reinforcing basket, the biasing device is arranged in a defined position below the reinforcing cage at the same time, so that a Sohlvorspannung is achieved at the sole of the recess.

Another aspect of the invention is that not only a supply line but also a derivative are attached to the reinforcement cage. The conduits may be formed as simple hoses or pipes which are supported and protected by the reinforcement cage. The biasing device itself is designed as a sheet-metal hollow body, which is easy and inexpensive to manufacture.

Another aspect is that the sheet-metal hollow body is not attached directly to the reinforcement cage in this common arrangement. If you were to weld the thin-walled, expandable sheet metal hollow body directly to the longitudinal bars or the stiffening ring of the reinforcing cage, the thin sheet could be damaged, break through or weakened. The sheet metal body would then be destroyed even at low pressures and burst. On the sheet metal body act pressures up to 100 bar during toughening of the sole. Rather, the hollow sheet body is attached via holders on the reinforcement cage.

According to the invention, the holders do not rigidly connect the sheet metal hollow body, in particular movably, to the metal bars of the reinforcing basket. Due to the indirect attachment of the sheet metal hollow body after hardening of the concrete during inflation can develop largely free and is not exposed by rigid attachment points additional constraints and disabilities, which prematurely or even at low pressures and small filling volumes prepare the inflation process and lead to the destruction of the sheet metal hollow body ,

It is envisaged that the holders hold the sheet-metal hollow body at a distance from the metal bars of the reinforcing cage and / or have a lower rigidity than the metal bars. By this indirect fastening of the sheet-metal hollow body to the reinforcing cage at a predetermined distance by means of separate holders ensures that when expanding the sheet-metal hollow body of the reinforcing cage does not damage this. In this case, the predetermined by the holders distance between the hollow sheet body and the reinforcement cage is greater than the maximum extent of the sheet metal hollow body.

A simple yet reliable attachment is inventively achieved in that the holders have metal strips which are attached on the one hand to the sheet metal hollow body and on the other hand to the metal bars of the reinforcing cage, in particular welded. In this case, the metal strips are preferably welded onto the upper side of the sheet-metal hollow body executed for the currency basket, in particular flatly. The thin, flexible metal strips can be bent in a simple manner and deformed for welding to the reinforcement cage. In this case, fastening can take place not only on the substantially longitudinally extending metal rods but also on transverse or circumferentially extending metal rods of the probation basket, in particular on a so-called base or a stiffening ring, which are arranged in the lower region of the reinforcement cage.

According to the invention, it is further preferred that a mouth opening of the feed line in the sheet-metal hollow body is spaced from a mouth opening of the discharge in the sheet-metal hollow body, wherein at least the mouth opening of the discharge line is arranged on an upper side of the sheet metal hollow body. The mouth opening of the feed line can preferably be arranged on the underside or in a side region of the hollow sheet metal body. Preferably, the distance between the two mouth openings is almost as large as the maximum extent of the sheet-metal hollow body. In this case, the two mouth openings can be arranged diametrically opposite one another. Preferably, a guide element is arranged between the two mouth openings in order to prevent a short-circuit flow between the two openings.

As a result, when using two different pressure media with different densities and viscosities it is ensured that, for example, during a first widening of the sheet metal hollow body by water, it can then be reliably displaced from the hollow body via the discharge by a second, self-hardening pressure medium, such as cement suspension. It is an advantage of the invention that the first pressure medium is not simply displaced in the exchange during the exchange in the surrounding soil area, but can be reliably led out via the discharge from the ground to the earth's surface. This is necessary to control the return and to ensure the success of the exchange of the media.

Basically, the reinforcing cage is adapted according to the shape of the recess, wherein the reinforcing cage is always slightly smaller than the cavity in which the reinforcing cage is to be inserted. For ease of insertion Ableitbleche or spacers may be provided on the outside of the reinforcing cage, which allow a good sliding at a predetermined distance from the cavity wall by wedge-shaped surfaces. Advantageously, according to the invention, the reinforcing cage is formed with an elongate, columnar arrangement and may, for example, have a round or rectangular cross-section.

It is further provided according to the invention that along at least a portion of the reinforcing cage several Verpressleitungen are arranged, each of which at least one Exit valve to the outlet of a curable fluid to increase a skin friction. The injection lines and the valves are arranged at least in a partial area along the length of the Bewehungskorbes and allow a targeted additional introduction of cement suspension in the shell region or lateral surface of the foundation element. In this way, the so-called skin friction between the outside of the foundation element and the surrounding soil can be increased, whereby the carrying capacity of the foundation element can be increased as a whole. This is particularly advantageous in the case of the sole prestressing according to the invention, in order to avoid premature lifting of the foundation pile from the ground due to the applied prestressing on the sole.

The injection lines can be designed according to the invention as Einzelverpressleitungen or Einzelpresslanzen, which preferably each have only one to two outlet valves at the lower end.

A preferred embodiment of the invention is that each injection line has a plurality of outlet valves. Along the tubular or tubular Verpressleitungen therefore several outlet valves are arranged with a predetermined distance from each other. In this case, in such a Verpressleitung a displaceable packer device can be introduced, which can direct by moving cement to the respective outlet valve cement paste to this outlet valve.

The packer device comprises two mutually spaced sealing washers or inflatable elements, which enclose a pressure chamber, which is supplied via a supply line with cement suspension.

In principle, the outlet valve can be designed in any suitable manner. It is particularly preferred according to the invention that at least one outlet opening is provided to form an outlet valve in the injection line, which is covered by an elastic sleeve. This sleeve-shaped sleeve can be a piece of a rubber hose, wherein the sleeve opens upon appropriate pressurization and the surrounding concrete breaks up, so that cement suspension from the injection line can pass through the outlet opening in the outer region or shell of the foundation element.

A particularly reliable mode of operation is ensured according to the invention in that a cover element is arranged in the region of the mouth opening of the supply line and / or discharge on the outside of the sheet metal hollow body. As a result, the sensitive line connection is protected in the sheet metal hollow body during later filling of the recess with concrete to form the foundation element.

The invention also includes a foundation element in the ground, which is created with a reinforcement according to the above description.

The second part of the object is achieved according to the invention by a method in which a reinforcement according to the preceding description is used. In this way, a high-strength foundation element can be created, in which a sole bias is applied in one or more steps.

According to the invention, it is preferred that a sole body is first created in the sole of the recess, in which prior to hardening of the sole body the hollow sheet metal body is immersed in the foot region of the reinforcement. The sole body is created in particular from a hardening cement suspension, wherein the sheet-metal hollow body is pressed in a still soft, uncured state in the sole body. In this way, a defined base for the hollow sheet metal body is created, with which a particularly good compression of the sole and thus a solid bias is achieved.

It is also according to the invention that after filling the recess and curing the filling material of the hollow sheet metal body by introducing a first pressurized fluid in one or more steps for biasing the sole, the foundation element is volume expanded. By this bias of the sole, the skin friction of the foundation element is activated while anticipating a subsidence of the sole. In this way, the carrying capacity is improved due to an increased peak pressure force of the footprint of the foundation element.

According to the invention, a particularly expedient method configuration consists in that, after the desired pretension has been reached, the first pressurized fluid is replaced by a second pressurized fluid which hardens. Thus, the biasing can be done first by a non-hardening first pressurized fluid, in particular by water. For an improved activation of the frictional forces, it may be expedient to carry this out gradually over a longer period of time, for example of a few days. The friction forces in the shell area represent the abutment for the applied peak pressure force and it can occur in some soils that higher shell friction forces can be achieved only by gradual and slow load increases. Will the final state of Preload reached, then the non-hardening pressure fluid can be replaced by a hardening second pressurized fluid, in particular a cement suspension. In this case, in particular, a mass is used which experiences no or only a small change in volume during curing. In this case, it is altogether according to the invention that the second pressure fluid is introduced through the supply line into the sheet-metal hollow body until the second hardening pressure fluid also exits at the discharge at the upper side of the foundation element. The sheet-metal hollow body is then reliably filled with the hardening pressure fluid, so that the sheet-metal hollow body remains permanently deformed with the generated bias.

A further advantageous variant of the method according to the invention is that a hardenable fluid is introduced into the shell region of the foundation element to increase the skin friction via injection lines to the reinforcement. By means of corresponding outlet valves on the injection lines, in particular cement suspension is introduced into the boundary region of the foundation element with respect to the surrounding soil. As a result, the skin friction and thus the carrying capacity of the foundation element is increased. This is preferably carried out before a sole prestressing takes place by inflating the sheet-metal hollow body in the foot region of the foundation element. In certain cases, however, the introduction of hardenable fluid into the jacket area can also take place after or at the same time as the sole prestressing.

The invention will be further described by means of preferred embodiments, which are shown schematically in the drawings. In the drawings show:

1 a schematic cross-sectional view through an inventively produced foundation element with a reinforcement according to the invention;

2 an enlarged detail view of the foot area of the foundation element of 1 ;

3 a plan view of a sheet-metal hollow body with holders; and

4 a schematic representation of the flow path within a hollow sheet metal body according to the invention in the exchange of pressurized fluid 1 against pressurized fluid 2 ,

For producing a foundation element according to the invention 5 is in the in the 1 and 2 illustrated embodiment in a floor 3 first a hole 4 introduced to a desired depth. The hole 4 can be used as uncased, cased or partially cased bore 4 to be created. The bore may be filled with or without support liquid, such as bentonite suspension or a polymer solution. How out 2 can be seen, first on a sole 8th a layered sole body 7 made of cement paste, mortar or concrete. Even before hardening of the sole body 7 In this the foot area becomes a reinforcement according to the invention 10 brought in.

The reinforcement 10 comprises a columnar reinforcing cage as an essential component 14 which consists of an arrangement of vertically extending metal rods 12a is formed, which extends over circumferentially extending horizontal metal rods 12b connected to each other. These are usually formed spirally or there are closed rings or brackets or stiffening rings. The connection of the metal bars 12a . 12b Can be done via welded joints or via connecting wires. At the bottom of the reinforcement cage 14 is at this a sheet metal hollow body 30 indirectly via holder 20 attached. The attachment of the sheet metal hollow body 30 does not take place rigidly at the reinforcement cage 14 , so that later during the biasing of the sole as small as possible constraints on the sheet metal envelope of the sheet-metal hollow body 30 result as its volume increases. This prevents damage and allows it to deform freely.

The sheet metal hollow body 30 serves as a lifting pad or biasing means and has in a preferred embodiment, two spaced-apart, approximately circular disk-shaped metal plates 28a and 28b on which at its outer edge over a slotted circularly bent pipe 26 tensile and bending resistant connected to each other. The individual joints between the pipe 26 and the metal plates 28a . 28b are fluid-tight connected via corresponding welds. Also the front sides of the circular bent pipe 26 lie abutting against each other and are welded fluid-tight. But it can also be used differently shaped and manufactured lifting cushion, such as sheet metal hollow body with convolutions.

To form the reinforcement according to the invention 10 runs along the drilling axis of the hole 4 on the inside of the reinforcement cage 14 a hose-like supply line 32 from the top of the reinforcement cage 14 up to the bottom-mounted sheet metal hollow body 30 , The supply line 32 flows through a mouth opening 36 in the interior of the sheet-metal hollow body 30 , In the same way extends from an approximately opposite mouth opening 38 a derivative 34 from the sheet metal hollow body 30 to the top of the reinforcement basket 14 ,

The supply line 32 can be connected to a pressure generating unit, not shown, with which a pressurized fluid in the interior of the sheet-metal hollow body 30 can be initiated. By a not shown closure device at the outlet of the derivative 34 so can inside the sheet metal body 30 be built up so high pressure that the hollow sheet body 30 expands, thus increasing its volume. In this way, after the expiration of the hole 4 with a cement or concrete mass and hardening of the foundation element 5 the sole 8th be biased. The bottom surface is pressed down and as a counterforce in the jacket area 6 the skin friction activated. The bias of the sole 8th increases the peak pressure force on the sole 8th and thus increases the carrying capacity of the foundation element 5 while minimizing the overall composition.

To further increase the load capacity by increasing the skin friction are at the reinforcement of the invention 10 at least at one part along the outside of the reinforcement cage 14 several injection lines 40 arranged, which outlet valves 42 have at predetermined locations. After filling the hole 4 and even before complete curing of the foundation element 5 can over the grout lines 40 and the outlet valves 42 Cement suspension under pressure in the jacket area 6 be injected, which is the interface between the foundation element 5 and the surrounding soil 3 represents. By injecting the cement suspension can increase the skin friction and thus the carrying capacity of the foundation element 5 be improved. As a result, then also a higher peak pressure force on the sole 8th be applied, since the abutment in the jacket area 6 shifts less upwards.

To form an exit valve 42 in the injection line 40 are in these outlet openings 44 introduced, which of a sleeve-shaped sleeve 46 are covered in rubber. When applying a fluid pressure within the injection line 40 can the cuff 46 Destroy the surrounding concrete or be stretched so far that the cement suspension can escape through the resulting cracks in the concrete in the desired manner in the mantle area.

According to an aspect of the invention, the sheet-metal hollow body is 30 , as in 3 represented by holders 20 at the reinforcement cage 14 attached. The holders 20 are according to the embodiment of 3 formed as a thin sheet metal strips, which on an upper side of the sheet-metal hollow body 30 are welded. By appropriate deformation of the thin holder 20 can this in production technology simple way to the metal rods 12 of the reinforcement basket 14 created and welded with these as well. During welding, the thin sheet metal of the sheet metal hollow body 30 not be damaged or weakened.

According to another aspect of the invention, the mouth openings 36 . 38 the supply line 32 or derivative 34 on the circular disk-shaped sheet metal hollow body 30 arranged at diametrically opposite locations, wherein the distance between the two mouth openings 36 . 38 slightly smaller than the maximum diameter of the hollow sheet body 30 is. When introducing a pressure fluid over the mouth opening 36 is thus ensured that this first the interior of the sheet-metal hollow body 30 good flow through, until it reaches the mouth 38 the derivative 34 as it gets in 4 is shown. In a biasing means of two different pressure fluids can be achieved so that when introducing the second pressure fluid, the previous first pressure fluid largely completely from the interior of the sheet-metal hollow body 30 is displaced. Optionally, in the inside of the sheet-metal hollow body 30 Even baffles be provided to an immediate short-circuit flow between the two orifices 36 . 38 to prevent.

Claims (15)

Reinforcement for a foundation element ( 5 ) in the ground ( 3 ), which metal rods ( 12 ) used to form a reinforcement cage ( 14 ) are connected to each other, at the foot region of a biasing means is arranged, wherein at least one supply line ( 32 ) and at least one derivative ( 34 ) are provided for supplying or discharging a fluid to the biasing means and to an upper portion of the reinforcing cage ( 14 ), characterized in that the biasing means comprises an expandable sheet metal hollow body ( 30 ), which via holders ( 20 ) on the reinforcement cage ( 14 ), that the holders ( 20 ) a lower rigidity than the metal rods ( 12 ), wherein the hollow sheet body ( 30 ) in total about the holders ( 20 ) when inflating movable to the metal rods ( 12 ) of the reinforcement cage ( 14 ), and that the supply line ( 32 ) and the derivative ( 34 ) on the reinforcement cage ( 14 ) are attached. Reinforcement according to claim 1, characterized in that the holders ( 20 ) the hollow sheet body ( 30 ) at a distance to the metal rods ( 12 ) of the reinforcement cage ( 14 ) hold. Reinforcement according to claim 1 or 2, characterized in that the holders ( 20 ) Have metal strip, on the one hand on the sheet metal hollow body ( 30 ) and on the other hand on the metal rods ( 12 ) of the reinforcement cage ( 14 ) are attached, in particular welded. Reinforcement according to one of claims 1 to 3, characterized in that a mouth opening ( 36 ) of the supply line ( 32 ) in the hollow sheet body ( 30 ) spaced from a mouth opening ( 38 ) of the derivative ( 34 ) in the hollow sheet body ( 30 ), wherein at least the mouth opening ( 38 ) of the derivative ( 34 ) on an upper side of the sheet-metal hollow body ( 30 ) is arranged. Reinforcement according to one of claims 1 to 4, characterized in that the reinforcing cage ( 14 ) has an elongated, columnar arrangement. Reinforcement according to one of claims 1 to 5, characterized in that along at least a portion of the reinforcing cage ( 14 ) several injection lines ( 40 ) are arranged, which in each case at least one outlet valve ( 42 ) to exit a curable fluid to increase a skin friction. Reinforcement according to claim 6, characterized in that each injection line ( 40 ) several outlet valves ( 42 ) having. Reinforcement according to claim 6 or 7, characterized in that for forming an outlet valve ( 42 ) in the injection line ( 40 ) at least one outlet opening ( 44 ) provided by an elastic cuff ( 46 ) is covered. Reinforcement according to one of claims 4 to 8, characterized in that in the region of the mouth opening ( 36 . 38 ) of the supply line ( 32 ) and / or derivative ( 34 ) at the top of the hollow sheet body ( 30 ) A cover is arranged. Foundation element in the ground ( 3 ) with a reinforcement ( 10 ) according to one of claims 1 to 9. Method for creating a foundation element ( 5 ) in the ground ( 3 ), wherein first a recess is created in the ground, in which a reinforcement ( 10 ) and which is filled with a hardenable filling compound, characterized in that a reinforcement ( 10 ) is used according to one of claims 1 to 9. A method according to claim 11, characterized in that first in the sole of the recess a sole body ( 7 ), in which prior to hardening of the sole body ( 7 ) of the sheet metal hollow body ( 30 ) at the foot of the reinforcement ( 10 ) is immersed. A method according to claim 11 or 12, characterized in that after filling of the recess and curing of the filling compound of the sheet metal hollow body ( 30 ) by introducing a first pressure fluid in one or more steps for biasing the sole of the foundation element ( 5 ) is volume expanded. A method according to claim 13, characterized in that after reaching the desired bias voltage, the first pressure fluid is replaced by a second pressure fluid which cures. Method according to one of claims 11 to 14, characterized in that via injection lines ( 40 ) at the reinforcement ( 10 ) a curable fluid in the cladding region ( 6 ) of the foundation element ( 5 ) is initiated to increase the skin friction.

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