WO2000036222A1

WO2000036222A1 - External prestressing member

Info

Publication number: WO2000036222A1
Application number: PCT/DE1999/003998
Authority: WO
Inventors: Karl SCHÜTT; Stephan Sonneck
Original assignee: Bilfinger + Berger Bauaktiengesellschaft
Priority date: 1998-12-16
Filing date: 1999-12-15
Publication date: 2000-06-22
Also published as: DE19858001A1; EP1141488A1

Abstract

The invention relates to a prestressing member which has at least one tension element (5) and a common sheathing (3) for all of its tension elements (5). The aim of the invention is to configure a prestressing member of this type in such a way that at least one spacer (9) is located inside the sheathing (3) in order to prevent the tension elements (5) from resting against the sheathing wall (16), at least in the area of the spacer (9). The invention also relates to a device for prestressing structures, comprising at least one prestressing member (4) which in turn comprises at least one tension element (5) and a common sheathing (3) for all of its tension elements (5); and at least one bearing device for the prestressing member (4), the bearing device being situated on the structure and comprising at least one shaped part (19) for deviating the prestressing member (4). The device is configured in such a way that the shaped part (19) can alternatively be arranged in a guide in such a way that it can slide and therefore move in relation to the structure together with the prestressing member when the prestressing member (4) is stressed.

Description

"External tendon"

The invention relates to a tendon with at least one tension element and a common cladding tube for all tension elements of the tendon.

Such tendons are used in practice for prestressing buildings of all kinds, and they often have to be guided over a deflection point or a deflection area. Care must be taken to ensure that there are no kinks in the cladding tube and in the tensile elements that impair the load-bearing capacity of the tendon. It is also important to ensure that the tension elements are not damaged or attacked by substances penetrating the cladding tube. After tensioning the tension elements, the cavity remaining in the cladding tube is therefore often filled with a hardening, space-filling mass, which not only increases the load-bearing capacity of the tendon, but also provides protection for the tension elements.

The present invention is based on the object of designing and developing the known tendon such that the tension elements are always and in particular also arranged at the deflection points at a minimum distance from the inner wall of the cladding tube.

The tendon according to the invention achieves the above object by the features of claim 1. Thereafter, the aforementioned tension member is designed such that at least one spacer is arranged within the cladding tube, which prevents the tension elements from contacting the cladding tube wall at least in the region of the spacer.

According to the invention, it has been recognized that, in addition to the tension elements, positioning aids for the tension elements can also be arranged within the cladding tube of a tendon. Furthermore, it has been recognized that the pulling elements can be kept at a distance from the cladding tube wall in a simple manner by means of a positioning aid in the form of a spacer.

In principle, the present invention can be implemented with various structural designs of a spacer. Has been particularly advantageous ben, however, ring-shaped or tubular spacers have been found, which are arranged quasi concentrically to the cladding tube. Such tendons are particularly easy to assemble and prefabricate, since the orientation of the spacers is otherwise not critical and the tension elements can be inserted into the tendon just as with conventional tendons, namely by guiding the tension elements through the annular or tubular spacers.

It also proves to be advantageous if the inner surface of the spacers, namely the surface on which the tension elements are supported, is rounded in the direction of the cladding tube axis. As a result, a kink-shaped course of the tension elements in deflection areas of the tendon can be defused or even avoided. In addition, with rounded inner surfaces of the spacers, the insertion of the tension elements into the cladding tube is simplified.

The cladding tube and the tension elements of a tendon are generally flexible, i.e. bendable, since tendons - as already mentioned - often have to be guided over deflection areas. In addition, tendons are usually pre-assembled at the factory and transported to the site in a drum. The tendon according to the invention also advantageously has the flexibility required for transport and installation in surrounding areas. For this purpose, the spacers could be designed to be at least as flexible in the direction of the cladding tube axis as the cladding tube itself. Another advantageous possibility is to arrange a plurality of narrow spacers within the cladding tube, so that the arrangement of the appropriately dimensioned spacers is flexible, in particular bendable, at least in the direction of the cladding tube axis , is. The arrangement of the spacers inside the cladding tube should in any case not significantly increase the bending stiffness of the cladding tube.

In a particularly advantageous variant of the tendon according to the invention, spacing elements are arranged between the spacers within the cladding tube, which ensure a minimum distance between two adjacent spacers. These spacer elements can advantageously also be annular or tubular and be arranged concentrically to the cladding tube, so that the tension elements both through the spacers and through the spacer elements are led. The inner surfaces of the spacer elements should be set back in relation to the inner surfaces of the adjacent spacer elements in the direction of the cladding tube wall, so that the traction elements can be completely embedded in the space-filling mass when the cladding tube is subsequently filled, at least in the region of the spacer elements.

With regard to the desired flexibility of a tendon, it is advantageous if the spacer elements are flexible, in particular bendable, at least in the direction of the cladding tube axis. Thin-walled tubes can be used as spacer elements, which have a certain flexibility due to a corrugated, perforated or slotted tube wall, for example.

The action of the spacer elements can be based on pressure contact with the adjacent spacers. In this case, the spacer elements and the spacers do not have to be connected to one another. In another variant of the tensioning element according to the invention, the spacers and the spacer elements are connected to one another in a chain-like manner, so that the spacer elements can also act to transmit tension. In this case, the spacer elements can also be implemented in the form of a wire structure or in the form of a textile structure.

The spacers and the spacer elements can either be arranged loosely in the cladding tube or can also be fixed within the cladding tube with the aid of fixing means. This proves to be particularly advantageous if the spacers are to be held in a specific, defined position. A screw could easily be provided as the fixing means, via which a spacer or a spacer element can be screwed to the cladding tube. Another possibility of fixing the position of spacers and / or spacing elements is to narrow the cladding tube under the diameter of the spacing elements and spacers.

Further advantageous embodiments of the tendon according to the invention are explained in connection with the exemplary embodiments shown in the figures.

Furthermore, the invention relates to a device for prestressing structures with at least one tendon, wherein the tendon has at least one tension member. ment and a common cladding tube for all tension elements of the tendon, and with at least one structure arranged on the bearing device for the tendon, wherein the bearing device comprises at least one molded part for deflecting the tendon.

As already mentioned, the cladding tube of a tendon is often filled with a hardening mass after assembly and after tensioning the tension elements. In particular in tendons with bare tension elements, the tensioning of the tension elements after hardening of the filling compound is generally no longer possible. The tension elements then form a bond with the cladding tube via the hardened mass, which in turn is in direct contact with the structure in the deflection areas and / or in the end anchoring areas of the tendon. The tension elements of the tendon are therefore either firmly connected to the structure after hardening of the filling compound or are at least in frictional engagement with the structure, so that the stretching of the tension elements and thus the tendon required for re-tensioning, if not prevented, is at least severely hampered .

Proceeding from this, the invention is further based on the object of designing and developing a device for prestressing buildings of the type described above in such a way that the tendon and in particular also a tendon with bare tension elements can be easily retensioned even after the filling compound has hardened.

The device according to the invention solves the above object by the features of claim 21. Thereafter, the above-mentioned device for prestressing structures is designed so that the molded part is optionally slidably mounted in a guide, so that the molded part together with the tensioning of the tendon Tendon can move relative to the structure.

According to the invention, it has been recognized that the re-tensioning of a tendon already filled with a hardening mass is favored by a relative movement between the tendon and the structure. Furthermore, it has been recognized that when the tendon is filled with a hardening mass, at least in tendons with bare tension elements, a relatively firm connection between the tendon and structure arises that cannot be overcome easily when the tendon is re-tensioned, ie not without damaging the tendon. According to the invention it is therefore proposed to provide a “desired sliding point” which is not arranged, for example, between the tendon and the structure, but between the molded part with which the tendon is in contact and which in itself is already attributable to the structure, and a guide for the molded part that is also attributable to the building

To promote the sliding movement, a sliding layer can advantageously be provided between the molded part and its guide. This could be implemented, for example, in the form of a sliding film or a layer of grease.

As already mentioned, the molded part is optionally slidably mounted in the guide. Accordingly, it is advantageous if easily operable means are provided for optionally fixing the molded part in the guide. These could be implemented in the form of a stop element which can be mounted on the guide and which could optionally be screwed to the guide. Such a stop element could then not only be simply assembled but also simply removed, namely in particular for retensioning the tendon. In contrast, during the assembly of the tendon and during tensioning of the tension elements before filling the cladding tube, the molded part can be fixed in its guide, since the tension elements can still be moved within the cladding tube.

In this context, it also proves to be advantageous if a layer is formed between the cladding tube of the tensioning member and the shaped part, which enables a constraint-free expansion of the cladding tube relative to the shaped part. Such a layer could be formed from a material with a viscous material behavior, for example from neoprene. In another advantageous variant of the device according to the invention, such a layer could be realized in the form of a brush bearing or also in the form of a carrier layer in which small rollers or balls are embedded. Finally, the possibility of realizing such a layer in the form of a loose sand mass should also be mentioned. Further advantageous refinements and developments of the device according to the invention for prestressing buildings are explained in the following description of exemplary embodiments with reference to the figures.

Finally, the invention also relates to a device for prestressing structures with at least one tendon, the tendon comprising at least one tension element and a common cladding tube for all tension elements of the tendon, and at least one bearing device arranged on the structure for the tendon, at least the tension elements of the tendon are guided out of the cladding tube through the storage device.

This device should also be designed so that the tendon and in particular a tendon with bare tension elements can be easily re-tensioned. For this purpose, it is proposed according to the invention to embed the tensile elements outside of the cladding tube, at least in regions, in a permanently plastic mass. This permanently plastic mass enables the tensile elements to expand in the correspondingly embedded areas even after the cladding tube has been filled with a space-filling mass and this mass has hardened.

In an advantageous variant of the device according to the invention, the tension elements are guided through a compensating chamber which is formed in the transition area between the cladding tube and the bearing device and can be filled with permanently plastic mass. The relative position of the two end walls of the compensating chamber can be changed by tensioning the tension elements, in particular also when re-tensioning the tendon.

Advantageous refinements and developments of this device according to the invention are also explained in more detail below on the basis of exemplary embodiments in conjunction with the figures.

Fig. 1 shows a longitudinal section through an inventive tendon guided over a deflection point;

Fig. 2 shows a cross section through the tendon shown in Fig. 1. 3 and 4 each show a cross section through a spacer.

Fig. 5 shows a longitudinal section through a further tendon according to the invention in a schematic representation.

Fig. 6 shows a longitudinal section through a further tendon according to the invention;

Fig. 7 shows a cross section through the tendon shown in Fig. 6.

Fig. 8 also shows a longitudinal section through a section of a further tendon according to the invention.

9 shows a longitudinal section through a device according to the invention for prestressing buildings in the region of a deflection point;

FIG. 10 shows a cross section through the device shown in FIG. 9.

11 to 13 each show a cross-sectional view through various devices according to the invention for prestressing buildings.

14 shows a longitudinal section through the end anchoring area of a tendon with a device according to the invention.

15 shows a longitudinal section through the end anchoring area of a tendon with a further device according to the invention for prestressing buildings.

16 and 17 show variants of this further device according to the invention for prestressing buildings in longitudinal section.

In Fig. 1, the deflection area 1 of a building is shown, over which a tendon 4 is guided. The tendon 4 comprises tension elements 5, which are arranged in a common cladding tube 3. Arranged in the deflection area 1 here is a molded part 2 assigned to the building, which can be made, for example, of concrete, fiber-reinforced concrete, metal or plastic. The contact surface 6 of the molded part 2 to the cladding tube 3 is designed as a guide for the cladding tube 3 in the longitudinal and transverse directions in order to avoid the occurrence of harmful kinks in the cladding tube 3 and the tension elements 5 of the tension member 4 in the deflection area 1. In the exemplary embodiment shown here for receiving the circular cladding tube 3, the contact surface 6 has an approximately semicircular contour in cross section, which is illustrated by FIG. 2. In longitudinal section, the contact surface 6 is continuously curved. The end regions 7 of the contact surface 6 are longer than theoretically required for the planned guidance of the cladding tube 3. In this way, positional tolerances from unplanned angular rotations of the tendon 4 relative to its planned position can be absorbed by the end regions 7 without the cladding tube 3 being damaged as it runs over the end edges 8 of the molded part 2.

Spacers 9 are arranged within the cladding tube 3, which have an approximately circular cross-section. The bundle of pulling elements 5, which are supported on the inner surface 10 of the spacers 9, is guided through the spacers 9. A spacer 11 is arranged between each two spacers 9. The spacer elements 11 also have an approximately circular cross section and ensure that a predetermined distance between the spacers 9 is maintained. The spacers 9 and the spacer elements 11 are introduced into the cladding tubes 3 before the pulling elements 5 are introduced into the cladding tube 3. The length of the spacers 9 and the spacer elements 11 is so short that it prevents the cladding tube 3 from bending, e.g. in the deflection area 2, do not oppose any appreciable resistance. The spacers 9 and the spacers 11 can therefore e.g. even before the cladding tube is placed in the building, e.g. in the tendon, are inserted into the cladding tube, and the cladding tube can then be rolled up and transported to the construction site, since the bending stiffness of the cladding tube is not significantly impaired.

The short length of the spacers 9 also has the advantage that the deflection angle between the individual spacers 9 in the deflection area 1 is so small that the resulting course of the tension elements 5 is only slightly bent and therefore not harmful. 3 shows how kinking of the tension elements 5 can additionally be avoided by means of a spherically shaped inner surface 13 of the spacers 9, which is particularly important in the case of tension elements sensitive to lateral pressure, such as those made of glass fiber composite elements. Fig. 4 shows another spacer 9, in which only the end regions 12a of the inner surface 12 are rounded. The shapes of the inner surfaces of the spacers 9 shown in FIGS. 3 and 4 also prevent the tension elements 5 of the tendon 4 from striking the end faces 12b of the spacers 9 when introduced into the cladding tube 3, which would impede the insertion of the tension elements 5.

The remaining cavity 14 in the cladding tube 3 can be filled with a space-filling mass 15 after tensioning the tension elements 5, which ensures that no substances that may damage the tension elements 5 can penetrate to the tension elements 5. As a rule, a hardening mass is used, which in the case of corrosion-sensitive steel tensile elements e.g. consists of corrosion-protecting cement mortar. By guiding the tension elements 5 on the inner surfaces 10, 12 or 13 of the spacers 9, it is ensured that the tension elements 5 maintain a distance from the inner wall 16 of the cladding tube 3, so that the filling compound 15 can flow around the tension elements 5 when filling. This ensures that the tension elements 5 are well embedded in the filling compound in those areas where they are not in contact with the inner spacer surfaces 10, 12 or 13. This distance of the tension elements 5 from the cladding tube 3 also ensures that substances which promote corrosion and possibly diffuse through the cladding tube wall can be intercepted by the enveloping layer of the filling compound.

Fig. 5 shows that and how the spacers 9 can be arranged in the cladding tube 3 without intermediate spacers.

As a rule, the close arrangement of the spacers 9 is only required in the deflection area 1 in order to be able to absorb the deflection forces resulting from the tensioned deflection forces as evenly as possible and to be able to remove them via the cladding tube 3 and the molded part 2 into the deflection area 1 of the structure. In the generally much longer, rectilinear area between two deflection points or between a deflection point and the end anchorage of the tendon, the spacers 9 can be arranged at greater distances. Fig. 6 shows how a longer spacer 18 ensures that two spacers 9 are held at a greater distance from each other. In the embodiment shown here For example, a thin-walled tube serves as a spacer element 18. If the cladding tube 3, with spacers 9 and spacer elements 18 already located therein, is to remain as flexible as possible for transport and installation in the building, a flexible spacer element 18 can be used to improve the flexibility, the flexibility of which can be achieved by a corrugated and / or perforated or slotted design of the tube wall can still be improved.

The previously described spacer elements 11 and 18 prevent the mutual approach of spacers 9 by pressure contact between the spacer element 11 or 18 and the adjacent spacer 9. For this purpose, the spacer elements 11 and 18 do not have to be connected to the spacers 9.

However, it is also possible to design the spacer elements 11 and 18 as tension-transmitting elements connected to the spacers 9, so that a chain of spacer elements 11 and 18 and spacers 9 is formed. The spacers 9 can be brought into position and held in that this chain is tensioned, individual spacers or spacer elements having to be held relative to the cladding tube 3 or the end anchorage of the tendon 4, e.g. by a screw 17. The tensile spacers z. B. from the described, optionally flexible pipes, from wires or textile elements, e.g. Weave, exist.

If the spacers are only to be arranged in a limited area, e.g. 1, the sliding of these spacers out of this area can also be prevented by attaching one or more spacers in this area to the cladding tube, e.g. with a screw.

FIG. 8 shows another possibility for preventing the spacers 9 from slipping out of a predetermined area: Here, the spacers 9 are located in a cladding tube 3 to which a cladding tube 3a with a smaller diameter is attached. Because of this smaller diameter, the spacers 9 cannot slip out of the cladding tube 3 into the cladding tube 3a. There is often the requirement that tendons, in particular external tendons with bare tension elements, should be retensionable. If the cladding tubes of such tendons are filled with hardened mass after the first prestressing and in this way there is a bond between the tension elements and the cladding tube, this retensioning is not readily possible. The cladding tube is then in contact with the structure, in particular in the deflection areas, but often also in the end anchoring areas, and the tendon there is either firmly connected to the structure after hardening of the filling compound or is at least in frictional engagement with it, so that the Tensioning required expansion of the tension elements and thus the tendon overall is either prevented or at least hindered.

If the tendon is not firmly connected to the structure in the anchoring areas and runs straight between the two end anchors, without a deflection point, the tendon can be freely stretched during re-tensioning even after the filling compound has hardened. The hardened mass is stretched by the same amount as the tension elements. In the case of cement mortar, this expansion is accompanied by the cement mortar being torn open, and in many cases the crack width is so small that there is no risk of corrosion for tensile elements made of steel. However, if there is a deflection point, free, uniform expansion in the area of the deflection point is not possible. There is then a risk that the tendon will be stretched over part of its length so that large cracks occur in the cement mortar, which means that the corrosion protection of the tension elements is no longer ensured. In another part of its length, e.g. In the area between the deflection point and the fixed end anchorage, the expansion applied to the tensionable end anchorage during re-tensioning is only partially effective if the free expansion of the tendon at the deflection point is prevented or is hampered by friction. In the transition areas from the large elongation to the low elongation of the tendon, there is a risk of the formation of large individual cracks in the hardened filling compound, with the result of inadequate corrosion protection.

Figures 9 and 10 show a deflection area 1 in longitudinal section or cross section. In the cladding tube 3 are the tension elements 5, which are held by the spacers 9 at a distance from the inner wall 16 of the cladding tube 3. The hollow Room 14 was filled with hardening compound 15 after the prestressing. The cladding tube 3 lies in the deflection molded part 19, which has an approximately semicircular cross section and which is guided through a component 20 with a correspondingly shaped surface 21. The component 20 thus forms a guide for the deflection molded part 19. Between the outer surface of the deflection molded part 19 and the surface 21 of the component 20, a sliding layer 22 is arranged, which can consist, for example, of a sliding film or a layer of grease. The sliding of the deflection molding 19 on the component 20 can be prevented by fastening the deflection molding 19 on the component 20, for example with the aid of a stop element 26 which is fastened to the component 20 with the aid of a screw 27.

It makes sense to prevent the sliding at least during the pretensioning of the tendon 4, so that the deflection molded part 19 remains in the position secured by the stop elements 26 during this pretensioning. When prestressing, the tension elements 5 then slide inside the cladding tube 3. However, the cladding tube 3 can also slide together with the tension elements 5 on the sliding layer 24 which is applied to the outer surface 25 of the cladding tube 3. When the tendon 4 is re-tensioned, the mass 15 has already hardened and the tension elements 5 can no longer slide within the cladding tube 3. The stop elements 26 are therefore removed at the latest before re-tensioning the tendon 4. During re-tensioning, the deflection molded part 19 now slides on the component 20 in the direction of the tension anchor, not shown here, namely in the direction of arrow 28. As a result, the tension elements 5 stretch not only in the area between tension anchor and deflection area 1, but also between this deflection area 1 and the fixed anchor of the tendon 4, whereby the cladding tube 3 and the mass 15 expand, possibly with crack formation in the hardened mass 15. In this way, the force applied during retensioning is effective over the entire tendon length.

Between the cladding tube 3 and the deflection molding 19, a layer 23 can additionally be arranged, which is designed such that the cladding tube 3 can stretch practically without constraint relative to the rigid deflection molding 19, without any sliding between this layer 23 and the cladding tube 3 on the one hand and the deflection molding 19 must occur on the other hand. Such a layer 23 can consist, for example, of neoprene or another material with a viscous material behavior. The layer 23 can also be designed as a kind of brush bearing, the "brush hairs" ablating the deflection forces between the cladding tube 3 and the deflection molded part 19, but they do not hinder the expansion of the cladding tube that occurs during re-tensioning, since they can bend transversely to their brush axis The same function can be performed by a layer 23, which consists of small rolls or balls, these balls or rolls can also be embedded in a possibly soft mass or other carrier layer, and a loose sand mass can also fulfill the function of the largely constraint-free mounting of the cladding tube .

FIGS. 11 to 13 show examples of deflecting molded parts 19 with an outer contour that is not round in cross section. In FIGS. 11 and 12 the cladding tube has a round cross section and in FIG. 13 a rectangular cross section.

In the case of a re-tensionable tendon, it must be ensured that the tension elements of the tendon can stretch freely even in the anchoring area, despite the now hardened mass that fills the cavity within the cladding tube.

14 shows the region 34 of the end anchorage of a tendon 4, the cavity 14 of which is filled with hardening mass 15. The tension elements 5 of the tendon 4 are anchored to a perforated disk 30 in a known manner with the aid of fastening elements 29, wedges are shown. The perforated disc 30 is connected to the cladding tube 3 via a tubular transition piece 32. For this purpose, the transition piece 32 is fastened in the case shown here with the aid of screws 33 to the perforated disk 30 and with the help of screws 35 on the cladding tube 3. The perforated disk 30 is supported on the anchor plate 31 via a flange 39 of the transition piece 32. At the end of the anchor plate 31, a pipe socket 36 is welded, which produces the transition to the recess pipe 37 concreted in the anchoring area 34.

For retensioning, a tensioning press is connected to the perforated disk 30 via an external thread 41 of the perforated disk 30. During re-tensioning, the perforated disc 30 is lifted off the anchor plate 31, the tension elements 5 being stretched. The width of the gap 38 which opens during re-tensioning between the flange 39 of the transition piece 32 and the anchor plate 30 corresponds to that of Retensioning applied tendon extension. This gap 38 is bridged by inserted, usually semi-tubular washers. Since FIG. 14 shows the anchoring area before retensioning, these washers are not shown here.

In many cases, the tendon is already deflected in the anchoring area, this deflection also being able to occur unintentionally due to positional tolerances of the anchoring area in relation to the structure. In the exemplary embodiment shown in FIG. 14, the tensioning member 4 is therefore formed at a short distance behind the perforated disk like a deflection point described in FIGS. 1 and 9 with inner spacers 9 and spacer elements 11. The Umienkformteil 19 receives the cladding tube 3. In the case of the re-tensionable tendon, the sliding layer 22 and possibly also e.g. viscous layer 24 arranged. Up to the point of prestressing, the deflection molded part 19 is fastened to the anchoring region 34 of the structure with the aid of a stop part 26 fastened to it and the screw 27. After the stop part 26 has been released, the tendon can move together with its cladding tube 3 and the deflection shaped part 19 in the direction of the tension anchorage.

15 shows an anchoring area in which the retensionability is achieved by other means. The tension elements 5 run within the anchoring area 34 in each case within a transition tube 42. The transition tubes have an external thread 43 at one end, with which they are screwed into an associated threaded hole in an intermediate plate 44. At the other end, the transition tubes 42 are each firmly inserted into an associated bore 46 in a sealing washer 45. The bore has a narrow area 47, which tightly surrounds the tension element 5 that is carried out. A second sealing disk 48 with narrow bores 49 is arranged at a distance from this sealing disk 45, the clear distance between the two sealing disks 45 and 48 corresponding at least to the intended tensioning path. The space 54 between the two sealing disks 45 and 48 forms a compensation chamber. This is closed with a push-over tube 55, one end of which is firmly connected to the transition cladding tube 50 and the other end of which slidably covers the cladding tube 3 with a sealing ring 56. The sealing disk 45 is connected to a transition cladding tube 50, which is arranged within the penetration 52 of the anchoring region 34 formed by a recess tube 51. If the axis of the anchoring region deviates from the tendon axis, the transition cladding tube 50 can rest against the trumpet-like rounded end widening 51a of the recess tube 51 without the tendon extending over an edge. After prestressing, the penetration 52 is sealed off from the transition cladding tube 50, for example by means of a shrink sleeve 53. The annular space 59 between each tension element 5 and its associated transition tube 42 is filled with permanently plastic mass, at least if the tension elements are to be protected against corrosion in this way. After prestressing, the cavity 54 between the two sealing plates 45 and 48 is also filled with permanently plastic mass 65, this mass being introduced through the filling opening 58 until it emerges from the ventilation opening 57. Both openings 58 and 57 are then closed with plugs 58a and 57a. Subsequently, the cavity 66 inside the cladding tube 3 and the cavity 52 of the penetration are filled with hardening mass, preferably with cement mortar, which ensures corrosion protection in the case of tension elements 5 which are at risk of corrosion. For this purpose, the cavity 52 of the penetration has an injection opening 60 and ventilation openings 29 and 67 in the high points. When filling, the cement mortar flows through the holes 63 located in the wall of the transition casing 50, so that the cavity 64 arranged on the outside around the transition casing 50 is also filled.

During later retensioning, the tensioning press is attached to the ends 5a of the tension elements 5 protruding from the perforated disk 30 in order to apply the tensioning stretch to the tension elements. The tension elements 5 slide in the transition tube rake 42 of the anchoring area. The hardened cement mortar filling of the cavity 66 is connected via bond forces to the areas 5a of the tension elements 5 therein and is retightened together with the tension elements 5a, the cladding tube 3 and the sealing disk 48 in the direction of the sealing disk 45, the cavity 54, ie the compensation chamber, reduced in size and the overflow tube 55 slides on the cladding tube 3. The excess permanent plastic mass located in the cavity 54 is displaced out of the previously opened opening 57. FIG. 16 shows an alternative possibility for realizing a compensating chamber 54. Here, the space between the two sealing disks 45 and 48 is not closed with a sliding tube which is at least slidably mounted on one side, but with a bellows element 70, which is also capable of a relative movement to allow between the two sealing washers 45 and 48.

In the variant shown in FIG. 17, the tension elements are guided outside the cladding tube individually in telescopically inserted transition tubes 71 and 72, which can be filled with a permanently plastic mass, but also form a protection for the tension elements 5 already unfilled. Here, the telescopic arrangement of the transition tubes 71 and 72 allows the tension elements 5 to be stretched when the tendon is re-tensioned.

Claims

Patent claims

1. tendon with at least one tension element (5) and a common cladding tube (3) for all tension elements (5) of the tendon (4), characterized in that at least one spacer (9) is arranged within the cladding tube (3), which is a concern the tension elements (5) on the cladding tube wall (16) are prevented at least in the area of the spacer (9).

2. Tensioning element according to claim 1, characterized in that the spacer (9) is annular or tubular, that the spacer (9) is arranged within the cladding tube (3) that the ring or tube axis is oriented parallel to the cladding tube axis and that the tension elements (5) are guided through the spacer (9).

3. Tendon according to one of claims 1 or 2, characterized in that the inner surface (12, 13) of the spacer (9) is rounded in the direction of the cladding tube axis.

4. tendon according to claim 3, characterized in that the inner surface (13) of the spacer is spherical.

5. tendon according to one of claims 1 to 4, characterized in that the cladding tube is flexible and that the spacer is flexible, in particular bendable, at least in the direction of the cladding tube axis.

6. Tendon according to one of claims 1 to 4, characterized in that the cladding tube (3) is flexible and that a plurality of spacers (9) are arranged within the cladding tube (3), the spacers (9) being dimensioned so that the The arrangement of the spacers (9) is flexible, in particular bendable, at least in the direction of the cladding tube axis.

7. tendon according to one of claims 1 to 6, characterized in that within the cladding tube (3) at least one spacer element (11) between two Spacer (9) is arranged and thus ensures a minimum distance between the two spacers (9).

8. The tendon according to claim 6, characterized in that the spacer element (11) is annular or tubular, that the spacer element (11) is arranged within the cladding tube (3) that the ring or tube axis is oriented parallel to the cladding tube axis and that the tension elements (5) are guided through the spacer element (11).

9. Tensioning element according to one of claims 7 or 8, characterized in that the inner surface of the spacer element (11) is set back in the direction of the cladding tube wall (16) relative to the inner surfaces (10) of the adjacent spacer elements (9).

10. Tensioning element according to one of claims 7 to 9, characterized in that the cladding tube (3) is flexible and that the spacer element (18) is flexible, in particular bendable, at least in the direction of the cladding tube axis.

11. Tendon according to one of claims 7 to 10, characterized in that the spacer element (18) is realized in the form of a thin-walled tube.

12. Tensioning element according to one of claims 7 to 11, characterized in that the spacer element (18) is realized in the form of a thin-walled tube with a corrugated, perforated and / or slotted tube wall.

13. Tensioning element according to one of claims 7 to 12, characterized in that the spacers (9) and the spacer element (11) are arranged individually in the cladding tube / 3).

14. Tensioning element according to one of claims 7 to 12, characterized in that the spacers (9) and the spacer element (11) are arranged in a chain-like manner in the cladding tube (3).

15. Tensioning element according to claim 14, characterized in that the spacer element is realized in the form of a wire structure or in the form of a textile structure.

16. Tensioning element according to one of claims 7 to 15, characterized in that the spacers (9) and the spacer element (11) are arranged loosely in the cladding tube (3).

17. The tendon according to one of claims 7 to 15, characterized in that fixing means for fixing at least one spacer (9) or the spacer element (11) are provided within the cladding tube (3).

18. Tensioning element according to claim 17, characterized in that at least one screw (17) is provided as the fixing means, via which a spacer (9) or a spacer element can be screwed to the cladding tube (3).

19. The tendon according to claim 17, characterized in that a narrowing of the cladding tube (3a) serves as a fixing means.

20. Tensioning element according to one of claims 1 to 19, characterized in that the cladding tube (3) is filled with a space-filling mass (15).

21. Device for prestressing structures with at least one tendon (4), the tendon (4) comprising at least one tension element (5) and a common cladding tube (3) for all tension elements (5) of the tendon (4), and with at least a bearing device arranged on the structure for the tendon (4), the bearing device comprising at least one shaped part (19) for deflecting the tendon (4), characterized in that the shaped part (19) is optionally slidably mounted in a guide (20), so that the molded part (19) can move relative to the structure when the tendon (4) is tensioned together with the tendon (4).

22. The apparatus according to claim 21, characterized in that a sliding layer (22) is arranged between the molded part (19) and the guide (20).

23. The device according to claim 22, characterized in that the sliding layer (22) is realized in the form of a sliding film or a grease layer.

24. Device according to one of claims 21 to 23, characterized in that means are provided for optionally fixing the molded part (19) in the guide (20).

25. The device according to claim 24, characterized in that the means for fixing comprise at least one on the guide (20) or the structure mountable stop element (26).

26. The apparatus according to claim 25, characterized in that the stop element (26) with the guide (20) or the structure can be screwed.

27. The device according to one of claims 21 to 26, characterized in that between the cladding tube (3) of the tendon (4) and the molded part (19) a layer (23) is formed, which is a non-constraining expansion of the cladding tube (3) the molded part (19).

28. The apparatus according to claim 27, characterized in that the layer (23) is realized from a material with a viscous material behavior, preferably from neoprene.

29. The device according to claim 27, characterized in that the layer (23) is realized in the form of a brush bearing.

30. The device according to claim 27, characterized in that the layer (23) is realized in the form of a carrier layer in which small rollers or balls are embedded.

31. The device according to claim 27, characterized in that the layer (23) is realized in the form of a loose sand mass.

32. Device according to one of claims 21 to 31, characterized in that the tensioning member (4) is a tensioning member (4) according to one of claims 1 to 20.

33. Device for prestressing buildings with at least one tendon (4), the tendon (4) comprising at least one tension element (5) and a common cladding tube (3) for all tension elements (5) of the tendon (4), and with at least a bearing device arranged on the structure for the tendon (4), at least the tension elements (5) of the tendon (4) being guided out of the cladding tube (3) through the bearing device, characterized in that the tension elements (5) outside the cladding tube (3 ) are at least partially embedded in a permanently plastic mass (65).

34. Apparatus according to claim 33, characterized in that the tension elements (5) through a trained in the transition region between the cladding tube (3) and the bearing device and with permanent plastic mass (65) fillable compensation chamber (54) are guided and that the relative position of the two end walls ( 45, 48) of the compensating chamber (54), can be changed by tensioning the tension elements (5).