Reinforcing device

Description

TECHNICAL SCOPE

The invention concerns a reinforcing device for supporting structures that comprises a lamellar structure that runs into an anchoring device. The said lamellar structure is composed of a plurality of separate or separable individual layers between which intermediate layers are disposed. The invention also relates to a method for producing such a reinforcing device and to a method for the reconstruction and/or reinforcement of edifices on the basis of such a reinforcing device

CURRENT TECHNOLOGICAL STATUS

International Patent Application PCT/CH98/00346 (published as WO99/10613) discloses a similar type of reinforcing device. In that device, the ends of CFK lamellae envisaged for the reinforcement of support elements, such as concrete supports, are separated into two layers of approximately equal thickness, and each is affixed into suitable supporting slots arranged at an angle to each other within an end element. This arrangement is then affixed onto the tension side of the support components, with the CFK lamellae pre-stressed in opposition to the support component directly over the end element as a precautionary measure. The end element can be set into a suitable indentation in the support component, or can be fixed directly onto the surface of the support component using adhesive and/or plugs, applying a transverse tensioning device if necessary.

Particularly in the area where this type of reinforcing device runs into the anchoring device, however, the untransmitted change in cross-section regularly results in considerable forces acting transversely to the main axis of the reinforcing device. This causes unwanted “pre-set breaking points” to be created in this similar type of reinforcing device. Over a period of time, these damage the reinforcing device, and can eventually affect its strength to such an extent that the whole device breaks.

In order to protect against this problem, therefore, a suitable transverse tensioning device is often used in the area where this type of reinforcing device runs into the anchoring device. However, this device is itself also subject to fault, and leads to additional complication and cost for the whole construction. Furthermore, it frequently results in the reinforcement device being stressed to its load limit and beyond in the direction of the main axis, such that a fault can occur in the load-bearing fixing of the lamellar structure in the area around the anchoring device.

DESCRIPTION OF THE INVENTION

The purpose of the invention under consideration here is therefore to overcome the disadvantages associated with the existing technological status, and to provide a reinforcement device that is unbreakable and able to withstand stress in the area around the entry into the anchoring device, and simultaneously to withstand a maximum loading of the supporting main anchorage in the direction of the main axis without any difficulty.

This purpose is fulfilled with the help of a reinforcing device in accordance with the invention. According to the characteristic features of claim 1, the reinforcing device for supporting structures as per this invention comprises a lamellar structure that runs into an anchoring device. This lamellar structure is composed of a plurality of separate or separable individual layers, between which intermediate layers are disposed, at least in some parts, and preferably in the area around the anchoring device. Methods for producing such a reinforcing device, and for the reconstruction and/or reinforcement of edifices on the basis of such a reinforcing device are also made available. Preferably, the lamellar structure is provided with carbon-fiber reinforced plastic lamellae (CFK) as the individual layers, which are embedded in a thermoplastic matrix. Preferably, the individual layers of the lamellar structure are based on a thermoplastic conventional plastic material and additionally have interposed fabric inserts or metal plates as the intermediate layers, most preferably a bidirectionally oriented fabric, especially a bidirectionally oriented aramide fiber fabric.

The invention relates to a reinforcing device for supporting structures, that comprises a lamellar structure that runs into an anchoring device. The lamellar structure is composed of a plurality of separate or separable individual layers, between which intermediate layers are disposed. Methods for producing such a reinforcing device, and for the reconstruction and/or reinforcement of edifices on the basis of such a reinforcing device are also made available. Preferably, the lamellar structure is provided with carbon-fiber reinforced plastic lamellae (CFK) as the individual layers, which are embedded in a thermoplastic matrix. Preferably, the individual layers of the lamellar structure are based on a thermoplastic conventional plastic material and additionally have interposed fabric inserts or metal plates as the intermediate layers, most preferably a bidirectionally oriented fabric, especially a bidirectionally oriented aramide fiber fabric.

The Method by which the Invention is Implemented

This invention relates to a reinforcing device for supporting structures, that comprises a lamellar structure that runs into an anchoring device. The lamellar structure is composed of a plurality of separate or separable individual layers, between which intermediate layers are disposed. Preferably, both ends of the lamellar structure in such a reinforcing device run into an anchoring device. In a preferred version, such a reinforcing device has a lamellar structure provided with carbon-fiber reinforced plastic lamellae (CFK) as the individual layers. Preferably, the individual layers of the reinforcing device are imbedded in a thermoplastic matrix. Preferably, the individual layers of the lamellar structure are based on a thermoplastic conventional plastic material. According to a further preferable version of the reinforcing device, fabric inserts or metal plates are additionally interposed as the intermediate layers, most preferably a bidirectionally oriented fabric, especially a bidirectionally oriented aramide fiber fabric. According to a preferred version of the reinforcing device, the anchoring device relates to a plurality, preferably two, hollow body segments connected to one of the hollow bodies spatially surrounding the lamellae ends. Cylinder bores running through the whole lamellar thickness can be used to connect, and preferably screw in, these hollow body segments. The use of a thermoplastic material is associated with a considerable additional advantage in this case, in that a heated instrument can be used in order to produce extremely well-targeted and carefully-positioned openings in the material, so that the imbedded carbon fibers can avoid the instrument, and therefore escape being damaged in any way by the drilling action. This has a correspondingly beneficial effect on the sturdiness of the entire reinforcing device, and therefore on its ability to withstand axial stress.

An alternative form of the design involves an anchoring device that has at least one axially-adjustable cylinder. In particular, the form preferably involves at least one cylinder, mounted so that it can rotate in an axial direction, and made of steel or, especially, made of a synthetic material reinforced by fiber, which can be provided with a set screw. In a preferred form of the design, the anchoring device involves a grip holder that can preferably be adjusted and locked with the help of an axially-driven threaded rod.

In addition, this invention also relates to a method for the manufacture of a reinforcing device as described above. The method is characterised in that it includes steps (a) to (d) below:

• • (a) the fanning out of conventional lamellae into a plurality of individual layers, in a manner that is of itself familiar;
  • (b) the interposing of a plurality of intermediate layers between the individual layers produced in accordance with (a);
  • (c) the fusion of the lamellar structure, preferably using the effects of heat and/or pressure, to produce a sandwich-like package;
  • (d) the fixing of the anchoring device, preferably with the help of a suitable clamping device.

According to an additional form of the design, a method that is in accordance with this invention is characterised in that it includes steps (a) to (c) below:

• • (a) the combination of a plurality of conventional individual layers in a conventional lamellar structure with a plurality of intermediate layers to form a lamellar structure, preferably arranged in an alternating manner. This procedure is of itself familiar;
  • (b) the fusion of the lamellar structure, preferably using the effects of heat and/or pressure, to produce a sandwich-like package;
  • (c) the fixing of the anchoring device, preferably with the help of a suitable clamping device.

A preferred design form for such a procedure is characterised in that the procedure is provided with an additional step, within which the cross-section of the lamellar structure in the area of the connection with the anchoring device is enlarged by the inclusion of additional individual layers and/or intermediate layers are included in the lamellar structure, preferably in an alternating manner.

An additional, preferred version of such a procedure is characterised in that both ends of the lamellar structure run into an anchoring device in each case.

An additional, preferred version of such a procedure is characterised in that the lamellar structure is provided with carbon-fiber reinforced plastic lamellae (CFK) as the individual layers.

An additional, preferred version of such a procedure is characterised in that the individual layers of the lamellar structure are imbedded in a thermoplastic matrix.

An additional, preferred version of such a procedure is characterised in that the individual layers of the lamellar structure are based on a thermoplastic conventional plastic material.

An additional, preferred version of such a procedure is characterised in that additional fabric inserts or metal plates are arranged as intermediate layers between the individual layers of the lamellar structure, most preferably, a bidirectionally oriented fabric, especially a bidirectionally oriented aramide fiber fabric.

An additional, preferred version of such a procedure is characterised in that the anchoring device relates to a plurality, preferably two, hollow body segments connected to the hollow body that spatially surrounds the lamellae ends.

An additional, preferred version of such a procedure is characterised in that the anchoring device involves at least one axially-adjustable cylinder, preferably at least one cylinder mounted so that it can rotate in an axial direction, made of steel, and with a set screw.

An additional, preferred version of such a procedure is characterised in that the anchoring device involves a grip holder that can preferably be adjusted and locked with the help of an axially-driven threaded rod.

In addition, this invention also relates to a method for the reinforcement and/or renovation of edifices, characterised in that at least one of the supporting construction elements of this edifice is fitted with a reinforcing device as described above within the framework of this method.

Finally, this invention relates to the use of a reinforcing device as described above for the reinforcement and/or renovation of edifices, preferably supporting construction elements based on concrete, particularly for the reinforcement of bridge constructions.

The following section of the text describes the preferred design forms of this invention in greater detail, with reference to the typical design examples disclosed in FIGS. 1 to 3:

DESIGN EXAMPLES

FIG. 1 shows an example of a reinforcing device in accordance with the invention, simultaneously illustrating the manufacturing method. The upper section of the figure provides a longitudinal sectional view, while a cross-sectional view is shown in the lower part of the figure. This version of the reinforcing device can preferably be manufactured as described in Steps 1 to 5 of the procedure below (metal plates can also be used as an alternative to the fabric inserts (1)):

• • 1. Division of the lamellae depth-wise (e.g. into 2-7 sections) in order to enlarge the surface:
    • a) To fan out conventional lamellae:
      • the lamellae can, for example, be divided depth-wise into the required number of component lamellae by using a heated cutting tool (e.g. knife or hot wire). This procedure protects the fibers better than the fanning out process for Duroplast lamellae that is already familiar (ref. publication WO 00/50706).
      • the fibers in the lamellae ends can be released out of the matrix by means of heating. The fibers can then be laid out in the required shape and fused into a grip holder.
    • b) An alternative method of manufacture can be carried out as follows:
      • a lamella is made up of several thin layers (known as tapes). These individual thin tapes are compressed together under heat and pressure to form a single lamella. Separating foils are interposed in the area of the anchoring device during the manufacturing process (the individual tapes are not bound within the required areas).
      • the anchoring head is manufactured from the tapes in a first step, and the free runs of the tapes are only welded together to form a lamella after this step has been carried out.
      • The lamella is provided with a bidirectional fabric between the tapes, preferably running throughout the entire depth (ref. Step 2).
  • 2. Insertion of bidirectional fabric (preferably aramide fabric with an orientation of +/−45°) with a thermoplastic matrix. A fabric is inserted into each 1^st separating layer that is created.
  • 3. In addition, the cross-section in the anchoring area can be enlarged by alternately affixing on a fabric and a thin (approx. 0.2 mm) lamella tape externally, if required.
  • 4. Heat and pressure are applied to fuse the sandwich-like lamella structure obtained in this way into a package. This step may have to be carried out in several stages (each individual layer).
  • 5. In the transition between the lamellae and the head, transverse stresses may occur as a result of the change in cross-section. A suitable device (e.g. steel and/or carbon fiber profile) can preferably be used to clamp them together, with the help of screws (3).

FIG. 2 describes other possible variations in accordance with the invention for the end anchoring of the reinforcing device into the anchoring device. The left-hand side of the figure provides a longitudinal sectional view, while the right-hand side shows a cross-sectional view.

Literature position EP 1 000 208 B1 (=WO 99/06651) discloses a similar type of design to the zigzag form of the lamella end shown in FIG. 2. According to a preferred version of the invention, the zigzag form is also curved in such a way that the variation in the lamella radiuses thus produced within the anchoring device creates a bending radius that is matched to the tension. This produces an additional reduction in the risk of the appearance of “predetermined breaking points”, as discussed above, in the area running into the anchoring device.

Possible manufacturing methods for this preferred version of the invention can be described as follows, where the anchoring components can be constructed from conventional plastic material or from metal;

• • 1. Zigzag form:
    • a) The zigzag form of the lamella end portion is produced first (e.g. by heating and compressing into a suitable mould), followed by its subsequent adjustment into a suitable positive and negative shape.
    • b) The end is fitted into a heated positive/negative mould, which shapes the lamella into the required zigzag configuration. This form is then left as the anchoring component on the lamella.
  • 2. Fixing the form at the zigzag lamella end piece:
    • The covering mould (made from a conventional plastic material or from metal) can be glued (B1), screwed (B2) or lashed completely around the edge surface (B3, e.g. with aramide, glass or, preferably, carbon fibers).

According to an additional, preferred, design, the anchoring device for a reinforcing device as described above can be based on a steel cylinder, as shown schematically in FIG. 3 (the upper area shows a longitudinal sectional view, while the lower area shows a plan view).

Possible manufacturing methods for this preferred version of the invention can be described as follows:

• • 1. In order that the lamella can be wound on such a small radius, it must be split apart (or it must have been split apart). This can take place in a similar manner to the version shown in FIG. 1 (Division of the lamellae depth-wise in order to enlarge the surface) (ref. above).
  • 2. The lamellar structure is wound on a cylinder made of steel, or preferably made of fiber-reinforced plastic. For fixing purposes, the various individual layers of the lamellar structure can be run through a slot, or they can be held mechanically (using a cross bracket and screws). A reduction in tension takes place as a result of the static friction between the cylinder and the CFK lamella. The surface of the cylinder should therefore preferably be selected to be as rough as possible.
  • 3. A compact component is produced by heating the head.

In relation to an additional preferred version, it is also possible to wind each individual layer of the lamellar structure around a separate cylinder made of steel, or preferably fiber-reinforced plastic, and therefore to construct the anchoring device on the basis of several cylinders.