EP2088259B1 - Device for pre-tensioning reinforcement elements on structures - Google Patents

Abstract

The method involves producing pre-tensioning between a building and a clamping shoe (1) attached at a reinforcement laminate-end by using a hydraulic cylinder-piston unit (9) that is utilized in a device for tensioning. Pre-tensioning is maintained by driving a set-screw between a tensioning device and the clamping shoe. The piston unit is removed under retention of the pre-tensioning held by the screw. The tensioning device and the shoe are removed from a building after hardening of an adhesive. The shoe is provided for clamping of the laminate-ends and a box-type metal body (3). An independent claim is also included for a device for pre-tensioning of reinforcement laminates at a building.

Description

The invention relates to a device for tensioning unidirectional fiber laminates with high tensile strength and tensile modulus of elasticity. The fiber laminates are bonded to the bending-stressed side of a concrete or reinforced concrete component under tension.

Devices for this purpose are known in the art and are already used for the prestressing of high-strength fiber laminates, for example, in the building repair or building upgrading. The end-side ends of the fiber laminates are clamped in a clamping shoe, which then has to be clamped in the direction towards the Faserlaminatende towards the building. In the previous systems, the tensioning device, which applies the tensile stress in the fiber laminate, left on the object until the curing of the adhesive, which is applied between the fiber element and the base concrete or reinforced concrete, is cured.

Out DE 102 49 266 B3 a device has become known, according to which is tensioned by means of hydraulic cylinders, in which case a blocking is carried out in the tensioned state. DE 198 49 605 A1 shows a device with which also by means of hydraulic cylinders is tensioned, in which case the clamping position is secured with spacers in the tensioned state.

The object of the present invention is to provide an alternative device, by means of which a bias voltage is generated, which stops during the curing of the adhesive, but the voltage building part of the device after the construction of the bias voltage is removable, so that this part to another Devices for building the required there bias can be used, that is successively flying on a variety of devices can be used. This should make the construction site process more flexible and faster.

This object is achieved by a device for biasing reinforcing laminates to buildings, consisting of a clamping shoe for clamping the exciting reinforcing laminate end and a box-like metal body, which forms a flat base plate below and forms an open box at the top, the metal body by means of his Underside projecting screws indirectly with a building zugkräftig connectable and has at one end two screws, which are outside out of the local metal body wall vertically extendable to strike the laminate side end wall of the clamping shoe, and an associated cylinder-piston unit which can be inserted into the box-like metal body is, so that its one side on the inner wall of the box-like metal body finds a stop, and is held on the opposite side of the cylinder in the box wall cut out for this purpose and the piston in the same direction as the screws through this box wall is extendable through, for acting on the laminate side end wall of the clamping shoe.

In the drawings, an embodiment of this tensioning device is shown at various stages of its application. With reference to these drawings, the tensioner will be described in detail and the method of tensioning by means of this tensioner will be explained.

It shows:

FIG. 1:

The clamping device seen in the application position obliquely from above, with a laid instead of a ceiling on a floor reinforcement laminate;

FIG. 2:

The clamping device in application position shown schematically from the side;

FIG. 3:

A bridge with the dowel screws introduced to prepare for applying a prestressed reinforcing laminate;

FIG. 4:

The bridge with the inserted dowel screws with adhesive applied and reinforcing laminate laid on top;

FIG. 5:

The bridge with glued and clamped by Endanankerungsplatten reinforcing laminate;

FIG. 6:

The bridge with the bonded and clamped reinforcing laminate with attached tensioning devices with regard to the pretensioning to be made.

As in FIG. 1 it can be seen that the device for prestressing reinforcing laminates on structures consists of a clamping shoe 1 for clamping the reinforcing laminate end 2 to be clamped and a box-like metal body 3 which forms a flat base plate at the bottom and forms an open box at the top. The metal body 3 is located on a Endverankerungsplatte, which is zugraäftig connectable by means of projecting from its underside dowel screws 4 with a building 5. The metal body 3 is connected very strongly to this Endverankerungsplatte about more screws 14. At one end, it has two setscrews 6, which are externally vertically extendable out of the local metal body outer side 7, to strike the laminate-side end wall 8 of the clamping shoe 1. The device further includes an associated cylinder-piston unit 9, which is insertable into the box-like metal body 3. In this case, its one side on the inner wall 10 of the box-like metal body 3 finds a stop, and on the opposite side of the cylinder 11 of the unit 9 is held in the box wall 12 cut out for this purpose. The piston 13 is extendable in the same direction as the set screws 6 through this box wall 18 and serves to act on the laminate side end wall 8 of the clamping shoe 1. The whole box-like metal body is preferably formed from an integrally machined from the solid aluminum block and has a length of about 30cm up. On its underside encloses a separate, to be lost in use, not visible here Endverankerungsplatte. The side walls 12 of the box-like metal body 3 are cut out from above, so that trapezoidal cutouts are formed. As a result, reinforcements are maintained, which reinforce the end walls together to increased traction.

The associated clamping shoe 1 consists of two hingedly connected parts 15,16, as shown in the FIG. 2 is apparent. These parts have mutually matching curved clamping surfaces, for accurately fitting inclusion of a reinforcing laminate end 20 are used, and which can be pressed against each other by means of screw 21. The end, directed in the direction of the clamped reinforcing laminate 2 wall 8 is at eingeklemmetem reinforcing laminate 2 perpendicular to the base side and is equipped with a concave Zentrierpfanne 22 as a coupling member into which the convex piston tip 23 fits. How to get by FIG. 2 further recognizes, the associated clamping shoe 1 is equipped on its front support edge with an angular plastic profile 17. The side walls 12 of the box-like metal body 3 are cut out, and the end walls are made as high as the cylinder-piston unit 9 inserted in the metal body in its then-lying state.

The application or the biasing process performed with this tensioning device will be described below with reference to FIGS FIGS. 3 to 6 described. The FIG. 3 shows this a building 5 in the form of a bridge, the left fix rests and on the right of a dilatation bearing 24. At a bridge reinforcing laminates are typically glued to the bottom to increase the clamping force of the building 5. First, in the building as in FIG. 3 shown screw dowel offset. The dowels are placed in the base made of concrete or reinforced concrete. Adhesive dowels or expansion dowels can be used. For example, four such dowels and screws 4 are displaced on each side. Here you can see only the front four screws 4, which obscure the view of the rear four.

Thereafter, the base is roughened and the adhesive 25 applied in the area where the fiber laminate 2 is applied, as in FIG. 4 shown. In the next step, the fiber laminate 2 is temporarily positioned in the adhesive. The strip-shaped reinforcing laminate 2 extends between the two rows of screws. Thus, only the front screws 4 are visible, while those behind the reinforcing laminate 2 are not visible. Subsequently, end anchoring plates 19 are applied to the reinforcing laminate 2 with another layer of adhesive 25 and tightened with the screws 4, so that the end anchoring plates 19 clamp the reinforcing laminate 2 in those places for provisional securing, as in FIG FIG. 5 shown. The adhesive 25 is not yet cured, so that therefore the reinforcing laminate 2 can still pull under tension on the adhesive layer.

In the next step, as in FIG. 6 shown, the tensioning devices are attached. For this purpose, the metal body 3 are screwed by means of separate fastening screws 14 on the Endverankerungsplatten 19 and braced vigorously with them. At the end-side ends 20 of the laminate 2, the clamping shoes 1 are mounted and by screwing their hinged parts, the reinforcing laminate 2 is clamped between these parts 15,16. The clamping shoes 1 are then on the building. Now, for biasing the reinforcing laminate 2 on its only one side of a hydraulic cylinder-piston unit 9 is inserted into the local metal body 3 and with a hand pump hydraulic fluid on the Hydraulic line 26 pumped into the same, so that the piston 13 extends and the clamping shoe 1 is applied. The pressure force used in this case is about 120 kN in the order of magnitude and the path due to the prestressing is 2 to about 15 mm, depending on the length of the reinforcing laminate. The coupling member in the form of the centering pan 22 ensures that the forces are introduced centrally into the fiber laminate. By means of the dome member in the form of the centering pan 22, eccentricities which arise during the clamping process are compensated. Namely, the unidirectional fiber laminate is incapable of absorbing eccentric stresses. Accordingly, the coupling member, that is, this centering pan 22 is of extraordinary importance for the clamping operation.

Once this bias has been generated hydraulically, the screws 6 are so twisted on the metal body 3, that they strike the clamping shoe 1 and thus hold the voltage. Now the hydraulic cylinder-piston unit 9 can be relieved again of the hydraulic pressure and then removed. Their use is therefore flying. This makes the construction site process more flexible and faster. Once after about 24 hours, the curing of the adhesive 25 is completed, the metal body 3 and the clamping shoes 1 can be removed. The setting start of the adhesive 25 is adjusted so that the beginning of curing of the adhesive takes place after the completion of the tempering process of the fiber laminate.

With the identical tensioning device, several fiber or reinforcing laminates can be pre-stressed on the same day. The pretensioning device is designed so that the tensioning device can be applied to both fin ends. In the case of on-site space problems, it is therefore possible, thanks to this clamping device, to carry out the clamping operation on the left or right-hand fin end.

Claims (6)

1. Device to preload laminates for reinforcement on buildings comprising a gripping shoe (1) for gripping the end (20) of the reinforcement laminate to be clamped and comprising a body made of metal (3) in the form of a box, the said body forming a lower plan base plate and an upper opened box, whereby the body made of metal can be linked indirectly by screws projecting from the lower side of the body made of metal; said screws being tightly connected with the building and said body made of metal comprising at one end two setting screws (6) coming out externally and perpendicularly from the wall of the body made of metal (18) located therein to butt against the end wall (8) of the gripping shoe (1) on the side of the laminate.
2. Device to preload reinforcement laminates situated on buildings according to claim 1, characterized in that the body made of metal (3) in the form of a box is constituted by an aluminium bloc which is cut in one piece from the solid and in that the said body presents on its lower face a separated end anchor-plate (19) which can be lost when used.
3. Device to preload reinforcement laminates situated on buildings according to claim 1 to 2, characterized in that the lateral walls (12) of the metal body (3) in form of a box are cut.
4. Device to preload reinforcement laminates situated on buildings according to claim 1 to 3, characterized in that the associated gripping shoe (1) is made of two parts (15, 16) which are connected to each other by means of hinges, e.g. of a lower part (15) having a curved gripping surface rising upwards together with an upper part (16) rising mirror inverted , whereby these two gripping surfaces can be pressed against each other by means of screw connexions (21) while an end of a reinforcement laminate (20) is included in an accurately fitting manner, and characterized in that the terminal wall which is oriented towards the reinforcement laminate to be gripped extends perpendicularly to the ground side in the case of a gripped reinforcement laminate (2); said terminal wall being equipped with a concave centring seat (23) of the piston (13) of the cylinder-piston unit (9).
5. Device to preload reinforcement laminates situated on buildings according to claim 1 to 4, characterized in that the corresponding gripping shoe (1) is equipped on its front lower edge with an angular profile (17) made of plastic, realised as a sliding part.
6. Device to preload reinforcement laminates situated on buildings according to claim 1 to 5, characterized in that the lateral walls (18) of the metal body (3) in form of a box are cut and in that the terminal walls are as tall as the piston-unit (9) according with its state once inserted in the metal body.

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