EP1980667B1 - Tension member for structures and method for its manufacture - Google Patents

Description

The invention relates to a tension member for structures according to the preamble of independent claim 1 and a method for its production according to the preamble of independent claim 19.

Generic tension members are known in structural engineering, especially in connection with cable-stayed and suspension bridges. But also in the production of roof structures, for example, for the roofing of stadiums, such tension members are used for concentrated load transfer.

In general, generic tension members consist of a plurality of tension members, such as steel rods, steel wires or steel strands extending within a tubular enclosure. To protect against corrosion, the individual tension elements are provided with a suitable coating and can additionally be arranged in a plastic casing. A bundle of such tension elements is additionally surrounded by a tubular sheath mostly made of polyethylene, on the one hand to protect the tension members against mechanical effects, on the other hand, to improve the corrosion protection in addition.

In the production of such tension members, the individual tension members are usually individually stretched gradually within the tubular sheath between the two anchor points connected by the tension member. For mounting the individual tension elements within the tubular casing, a certain free residual cross-section remains between the tension elements and the inner wall of the tubular casing. This free residual cross section also allows subsequent replacement of tension members in the course of maintenance and repair or subsequent addition of a tension member to further tension elements to increase the load capacity of the structure.

However, this type of construction implies that under certain circumstances, such as in the presence of wind load, the tubular envelope and the traction elements extending therein move transversely relative to one another, which may result in banging and rattling noises, but also an additional one dynamic stress of the tension member means.

From the WO 2005/049923 A1 a device for damping the vibrations of the tension members of a cable-stayed bridge is known. This device provides perpendicular to the tension members extending connecting struts, which surround the tension members like a sleeve. In these breakpoints, the free residual cross-section between the tubular casing and the tension elements is filled by a rigid packing to better absorb the radially acting forces in the breakpoints can. Vibration dampers in the area of the struts prevent larger vibrations.

From the EP 1 357 229 A1 is a tension member for cable-stayed bridges is known, which is also formed of a plurality of extending within a tubular sheath tensile elements. There is proposed to avoid transversal movements of the individual tension elements within the tubular enclosure, to introduce a hardenable mass, for example foam, in the enclosure. In this case, however, the uncontrollable spread of the filling medium within the cladding tube and the adhesion of the filling medium to the tension elements turns out to be disadvantageous, which means that individual tension elements in the course of maintenance or repair or subsequent reinforcement can not be changed. Also, the filling material can not be removed later or only with disproportionate effort again. By relative movements of the sheath and the tension elements in the longitudinal direction due to temperature or load changes, there is also the danger that the filling material is destroyed.

Another way to keep the tubular enclosure at a distance from the individual tension elements, is from the EP 0 169 276 A1 known. There runs axially parallel and extending over the entire length of the tension member between the tubular casing and the bundle of tension members a hose member which can be brought by filling with a filler material both with the inside of the tubular casing and the tension elements in contact. In this way, a linear support of the tubular casing along the entire stay cable is achieved.

Here, the course of the tubular element proves to be disadvantageous over the entire length of the tension member. First of all, larger quantities of filler material are needed, which proves to be uneconomical. In addition, high pressures for complete filling of the tube with a filler material are required for the filling process due to the large length of the tubular element and its flow resistance. In order to absorb these pressures, the hose element must be correspondingly elaborately reinforced. But also the mechanical equipment required for filling must be able to generate such high pressures. On the equipment side is therefore to be expected considerable costs in the acquisition and operation.

In order to achieve a complete filling of the hose element at moderately moderate pressure conditions, one is dependent on a low-viscosity filler with the disadvantage that even the smallest leaks in the hose element lead to leakage of the filling. The use of pitted material, however, is excluded because this can not be pressed over the entire length of the tubular element.

From a static point of view that is in the EP 0 169 276 A1 disclosed tension member is not able to selectively take on the tubular casing attacking forces such as connecting struts between the individual stay cables, since on the one hand, the filling material can yield under radial compressive forces in the axial direction and on the other hand, the free residual cross section of the tubular casing is not complete, but only partially filled.

In addition, the reveals DE 1 104 155 A a method and apparatus for protecting prestressed concrete structures from frost damage. There, attention is drawn to the problem that water accumulations can form in the cavities between the tendons and the casing, which can freeze when frozen and cause damage as a result of the resulting explosive effect. By providing elastically yielding elements in the cavities between the tendons and the enclosure, escape spaces are created into which the freezing water can expand and thus lose its explosive action.

Against this background, the invention has for its object to provide a tension member and a method for its production, with which these disadvantages are eliminated.

This object is achieved by a tension member and a method for its production according to the preamble of the independent claims 1 and 19.

Advantageous embodiments will be apparent from the dependent claims.

Fig. 1

eine Ansicht auf eine Schrägseilbrücke mit erfindungsgemäßen Zuggliedern,

Fig. 2

einen Teillängsschnitt durch das in Fig. 1 dargestellte Zugglied im Bereich II mit befülltem Füllkörper,

Fig. 3

einen Querschnitt durch das in Fig. 2 dargestellte Zugglied entlang der dortigen Linie III-III,

Fig. 4

einen Teillängsschnitt durch das in Fig. 1 dargestellte Zugglied vor dem Befüllen des Füllkörpers,

Fig. 5

einen Querschnitt durch das in Fig. 4 dargestellte Zugglied entlang der dortigen Linie V - V,

Fig. 6

einen Teillängsschnitt durch das in Fig. 1 dargestellte Zugglied während des Befüllens des Füllkörpers,

Fig. 7

einen Teillängsschnitt durch eine weitere Ausführungsform eines erfindungsgemäßen Zugglieds,

Fig. 8

einen ersten Querschnitt durch das in Fig. 7 dargestellte Zugglied entlang der Linie VIII - VIII, und

Fig. 9

einen weiteren Querschnitt durch das in Fig. 7 dargestellte Zugglied entlang der Linie IX - IX.

The invention will be explained in more detail with reference to an embodiment shown in the drawings. It shows

Fig. 1

a view of a cable-stayed bridge with tension members according to the invention,

Fig. 2

a partial longitudinal section through the in Fig. 1 illustrated tension member in area II with filled packing,

Fig. 3

a cross section through the in Fig. 2 illustrated tension member along the local line III-III,

Fig. 4

a partial longitudinal section through the in Fig. 1 illustrated tension member before filling the filling body,

Fig. 5

a cross section through the in Fig. 4 illustrated tension member along the local line V - V,

Fig. 6

a partial longitudinal section through the in Fig. 1 illustrated tension member during filling of the filling body,

Fig. 7

a partial longitudinal section through a further embodiment of a tension member according to the invention,

Fig. 8

a first cross section through the in Fig. 7 illustrated tension member along the line VIII - VIII, and

Fig. 9

another cross section through the in Fig. 7 illustrated tension member along the line IX - IX.

The present invention will be described below with reference to FIGS Fig. 1 illustrated, a valley-shaped substrate 1 bridging cable-stayed bridge 2 explained. In Fig. 1 is selected a representation in which the proportions in the longitudinal and transverse directions are not respected in favor of a clearer representation.

One sees a pylon 3 arranged centrally in the valley-shaped base 1, which in the present example consists of concrete, but can also be formed by a steel construction. In the lower part of the pylon 3 forms the central support for the superstructure 4, while the ends are supported directly by abutment from the ground 1. In addition, the superstructure 4 is held by tension members 5 in the form of stay cables, of which on both sides of the pylon 3, representative of several, one each is shown. In this case, the left tension member 5 is shown in a view, while the right tension member 5 is shown in a longitudinal section. The two tension members 5 extend obliquely each of an upper anchorage 6 in the head of the pylon 3 to a lower anchorage 7 in the superstructure.

The closer construction of the tension members 5 results from Fig. 2 that the in Fig. 1 with II indicated partial section shows, as well as from Fig. 3 in the form of an associated cross-section.

First, one sees there the tubular sheath 8, arranged along the longitudinal axis 9 of the tension member 5. The tubular sheath 8 has a circular cross-section, which is filled in the upper part of the tension elements 10. The tension elements 10 each consist of a plastic-coated wire strand, which are combined in their multiplicity to form a tensioning bundle. Such a tensioning bundle is able to absorb the existing loads on the structure and remove it via the pylon 3 in the substrate 1.

Since the tension elements 10 do not fill the entire cross section of the tubular sheath 8, a free residual cross section 11 remains in the lower region, which forms a continuous cavity over the length of the tension member 5. The free residual cross section ensures the longitudinal displaceability of the tubular envelope 8 with respect to the tension elements 10.

In the region of the free residual cross-section 11, one also sees in the axial direction over the length of a longitudinal section L of the tension member 5 (FIG. FIG. 1 ). The packing 12 has a deformable casing 13, which in the present example consists of a fabric-reinforced plastic. Both the upper end 14 and the lower end 15 of the shell 13 are sealed.

In the area of the upper end 14, a first opening 16 extending radially to the longitudinal axis 9 is inserted into the casing 13, through which opening a filling connection 17 provided with an external thread extends. In a corresponding manner is in the region of the lower end 15, a second opening 18 in which a likewise provided with an external thread discharge port 19 is arranged. About the mutually braced threaded nuts 21 and 22, both the filling nozzle 17 and the discharge nozzle 19 is tightly and non-positively connected to the shell 13 of the packing 12.

In the region of the connecting pieces 17 and 19, the tubular sheath 8 has larger openings 23 through which the stubs 17 and 19 extend radially. In this case, each one provided with a stepped Randfalz Covering 24, which in turn is penetrated by the nozzle 17 and 19, the openings 23 positively. A respectively screwed onto the nozzle 17 and 19 nut 25 ensures the tight fit of the respective nozzle 17 and 19 on the cover 24 and thus on the envelope 8. The end of the nozzle 17 and 19 carries a cap 26 for closing the openings.

The filling body 12 is filled with a filling medium 27, for example consisting of loose grains, so that over the entire longitudinal section L of the tension member 5, the free residual cross-section 11 is filled by the filling body 12. Thus, in the area L, a construction which is pressure-resistant with respect to radial forces is formed, which on the one hand prevents transverse relative movements between the tension elements 10 and between the tension elements 10 and the enclosure 8, but on the other hand permits relative movements in the longitudinal direction between the enclosure 8 and the tension elements 10. In addition, the pressure-resistant construction exerts a reinforcing effect for the connection in the FIGS. 2 and 3 only partially shown holding device 28, which has a tension member 5 cuff-like encompassing retaining ring 29 and connect to the struts 30.

The process for producing a tension member 5 according to the invention will be described below with reference to FIG Fig. 2 to 6 explained in more detail. First, one or more longitudinal sections L are fixed to the tension member 5, wherein clues are given for their concrete arrangement by the maximum free length of the tension members 5 and of holding points for externally acting holding devices 28.

If the concrete arrangement of the longitudinal sections L is fixed over the length of the tension members 5, then an upper and a lower opening 23 are bored in each longitudinal section L into the tubular enclosure 8 at its lower side. The arrangement of two such openings 23 is merely to be understood as an advantageous embodiment of the invention, in a simpler embodiment of the invention even a bore 23 is sufficient.

Subsequently, the longitudinally or multiply folded packing 12 is passed through the upper opening 23 and thereby inserted into the remaining free cross section 11 of the tubular casing 8 until the filling nozzle 17 in the upper opening 23 and the discharge nozzle 19 in the lower opening 23 to lie comes and this penetrates radially. After attaching the cover 24 on the stub 17 and 19 and fixing the same with the nut 25, wherein the cover 24 are positively supported by means of their circumferential Stufenfalzes at the edge of the opening 23, each of the nozzle 17, 19 forms an anchoring of the packing 12 within the tubular envelope 8 against slipping in the axial direction.

In this state, the sheath 13 is tension-free in the remaining cross-section 11 between the tubular sheath 8 and the tension members 10th

The in Fig. 6 illustrated next step provides the filling of the filling body 12 with a filling medium 27 before. For this purpose, a filling device is connected to the filling nozzle 17, of which only the filling hose 31 can be seen. The filling medium 27 in the form of a granular material, for example, is blown by means of overpressure in the direction of arrow 20 into the filling body 12. The venting of the packing 13 takes place in the present example on the discharge nozzle 19, which may be slightly opened for this purpose.

When providing only one piece venting during the filling process can also be done via the filling itself, in which case the filling medium 27 trickles only by gravity in the packing 13. Alternatively, it is possible to form the shell of the filler gas-permeable, so that while the granular filling medium 27 is held within the shell 13, but the displaced air escapes through the shell 13 into the tubular enclosure 8.

With increasing degree of filling takes a radial clamping of the shell 13 to their concerns under pressure to the tubular casing 8 on the one hand and the Tensile elements 10 on the other hand instead, wherein the shell 13 follows the contour of the free residual cross-section 11. After complete filling of the filling body 13 is finally in the FIGS. 2 and 3 shown state reached. All that remains is to disassemble the filling hose 31 and to close the connecting pieces 17 and 19.

If the backfilling of the filling body 12 is canceled at a subsequent time or the filling body 12 has to be dismantled as a whole, emptying of the filling body 12 can be achieved by opening the connection pieces 17 and 19. By gravity, for example, the granular filling medium 27 trickles out of the filling body 13. The emptying of the filling body 13 can additionally be assisted by a flushing stream introduced through the filling nozzle 17, for example by a gas or a liquid introduced under pressure.

Another embodiment of the invention is in the Fig. 7 to 9 shown, wherein identical parts are provided with the same reference numerals with the first embodiment.

One also sees a filled with a filling medium 27 filler 12 ', which is arranged in the free residual cross section 11 of the tubular casing 8. In contrast to the embodiment described above, the filling body 12 'has at its upper axial end 14' an upper opening 16 'and at its lower axial end 15' an opening 18 ', both with axial but opposite orientation in the free residual cross section 11 of tubular enclosure 8 have.

About not shown filling and emptying a filling hose 35 is connected to the upper opening 16 ', which is connected to the upper anchoring point 6 of the tension member 2 ( Fig. 1 ) and leads to the lower opening 18 'an emptying hose 36, which leads to the lower anchorage 7 of the tension member 2.

By a tensile design of the hoses 35 and 36 and their end-side attachment in the region of the anchors 6 and 7, a position securing the filling body 12 is achieved against axial slippage within the tubular enclosure 8.

The filling or emptying of the packing 12 'takes place from the free end of the hoses 35 and 36 in the region of the anchors 6 and 7. Similarly, the disassembly or an axial change in position of the packing 12' indirectly via the hoses 35 and 36 of the anchors 6 and 7 can be reached from.

Claims (24)

1. Tension member for structures, in particular a stay cable for a cable-stayed bridge (2), comprising a tubular sheath (8), inside which run one or more tension elements (10), for example steel rods, steel wires or steel strands, the tension elements (10) filling only part of the cross section of the tubular sheath (8) so that a remaining unoccupied cross section (11) is left, a filler body (12, 12') being arranged in the remaining unoccupied cross section (11) of the tubular sheath (8) for securing the tension elements (10) against transverse movement inside the tubular sheath (8), the filler body (12, 12') extending over a limited longitudinal portion L of the tension member (5) and having a deformable jacket (13, 13') that encloses a hollow space that is delimited on all sides and can be filled with a filler medium (27), characterised in that the filler body (12, 12') has at least one opening (16, 16', 18, 18') by means of which the hollow space, surrounded by the jacket (13, 13'), can be filled and/or drained.
2. Tension member according to claim 1, characterised in that the filler medium (27) consists of a granular material, preferably of sand or granulate.
3. Tension member according to claim 2, characterised in that the granular material has a substantially uniform particle size.
4. Tension member according to claim 1, characterised in that the filler medium (27) consists of a flowable or viscous material, preferably a liquid, a gel, or a liquid/solid mixture.
5. Tension member according to any of claims 1 to 4, characterised in that the filler medium (27) can be hardened.
6. Tension member according to claim 1, characterised in that the filler medium (27) consists of a gas.
7. Tension member according to any of claims 1 to 6, characterised in that the jacket (13, 13') consists of a deformable material, preferably of a resilient material such as rubber or plastics material.
8. Tension member according to any of claims 1 to 7, characterised in that the jacket (13, 13') of the filler body (12. 12') consists of a composite material.
9. Tension member according to claim 8, characterised in that the jacket of the filler body (12, 12') has a strength-reinforcing fabric.
10. Tension member according to any of claims 1 to 9, characterised in that the jacket (13, 13') rests against the tension elements (10) without being bonded.
11. Tension member according to any of claims 1 to 10, characterised in that the filler body (12, 12') has a first opening (16, 16') and a second opening (18, 18'), and the first opening (16, 16') is arranged at one end (14, 14') of the filler body (12, 12') and the second opening (18, 18') is arranged at the axially opposite other end (15, 15') of the filler body (12, 12').
12. Tension member according to any of claims 1 to 11, characterised in that a fill fitting or drain fitting (17, 19), which extends through the tubular sheath (8) of the tension member (5), is provided in the region of the at least one opening (16, 16', 18, 18').
13. Tension member according to claim 12, characterised in that the fill fitting or drain fitting (17, 19) is attached to the tubular sheath (8) in a force-locked manner.
14. Tension member according to any of claims 1 to 13, characterised in that the filler body (12, 12') is secured against slippage in the axial direction inside the tubular sheath (8).
15. Tension member according to any of claims 1 to 14, characterised in that the at least one opening (16', 18') terminates axially in the remaining unoccupied cross section (11) inside the tubular sheath (8), where it is connected to a fill hose or drain hose (35, 36) that leads to the end of the tension member (5) inside the tubular sheath (8).
16. Tension member according to claim 15, characterised in that the fill hose or drain hose (35, 36) is made of a material resistant to stretching.
17. Tension member according to either claim 15 or claim 16, characterised in that the fill hose or drain hose (35, 36) has a smaller diameter than the diameter of the remaining unoccupied cross section (11).
18. Tension member according to any of claims 15 to 17, characterised in that the fill hose or drain hose (35, 36) is secured against slippage in the axial direction inside the tubular sheath (8).
19. Method for producing a tension member (5) according to any of claims 1 to 18, characterised by the following steps:

    - fixing at least one axially delimited longitudinal portion L on a tension member (5) in which the securing and/or reinforcement is to take place;

    - introducing an empty filler body (12, 12') into the remaining unoccupied cross section (11) between the tubular sheath (8) and the tension elements (10); and

    - filling the hollow space of the filler body (12, 12') with a filler medium (27) until the remaining unoccupied cross section (11) is filled in the region of the selected longitudinal portion L.
20. Method according to claim 19, characterised in that at least one opening (23) is made in the tubular sheath (8) and the filler body (12) is pushed axially through this opening (23) into the remaining unoccupied cross section (11) between the tubular sheath (8) and the tension elements (10).
21. Method according to claim 19, characterised in that the filler body (12') is introduced into the remaining unoccupied cross section (11) between the tubular sheath (8) and the tension elements (10) by axial displacement starting from one opening (23) at one end of the tension member (5).
22. Method according to either claim 20 or claim 21, characterised by a pulling device with which the filler body (12') is pulled in the remaining unoccupied cross section (11) between the tubular sheath (8) and the tension elements (10) in the region of the predetermined longitudinal portion L.
23. Method according to any of claims 19 to 22, characterised in that the filler body (12, 12') is anchored in the appropriate longitudinal portion L of the tension member (5).
24. Method according to any of claims 19 to 23, characterised in that filling the filler body (12, 12') with a filler medium (27) takes place at the same time as air is vented from the filler body (12, 12').

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