CA1300855C - Corrosion protected tension member for use in prestressed concrete and method of installing same - Google Patents
Corrosion protected tension member for use in prestressed concrete and method of installing sameInfo
- Publication number
- CA1300855C CA1300855C CA000561230A CA561230A CA1300855C CA 1300855 C CA1300855 C CA 1300855C CA 000561230 A CA000561230 A CA 000561230A CA 561230 A CA561230 A CA 561230A CA 1300855 C CA1300855 C CA 1300855C
- Authority
- CA
- Canada
- Prior art keywords
- anchoring
- tension
- corrosion
- tension member
- set forth
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/08—Members specially adapted to be used in prestressed constructions
- E04C5/12—Anchoring devices
- E04C5/122—Anchoring devices the tensile members are anchored by wedge-action
-
- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D11/00—Suspension or cable-stayed bridges
- E01D11/04—Cable-stayed bridges
-
- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D19/00—Structural or constructional details of bridges
- E01D19/14—Towers; Anchors ; Connection of cables to bridge parts; Saddle supports
-
- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D19/00—Structural or constructional details of bridges
- E01D19/16—Suspension cables; Cable clamps for suspension cables ; Pre- or post-stressed cables
-
- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D2/00—Bridges characterised by the cross-section of their bearing spanning structure
- E01D2/04—Bridges characterised by the cross-section of their bearing spanning structure of the box-girder type
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/08—Members specially adapted to be used in prestressed constructions
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/08—Members specially adapted to be used in prestressed constructions
- E04C5/12—Anchoring devices
-
- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D2101/00—Material constitution of bridges
- E01D2101/20—Concrete, stone or stone-like material
- E01D2101/24—Concrete
- E01D2101/26—Concrete reinforced
- E01D2101/28—Concrete reinforced prestressed
Abstract
ABSTRACT OF THE DISCLOSURE
A corrosion-protected tension member, such as a tendon for prestressed concrete with post-tensioning, is made up of a bundle of individual tension elements, such as strands, ar-ranged within a tubular envelope. The tension member extends between anchoring devices, each forming an anchor region for the tension member with a free region located between the anchor regions. In the free region, the tubular envelope is formed of a sheathing tube. Each individual element is located within a separate sheathing duct, and a corrosion-protection mass fills the space within the ducts about the elements. The open volume within the sheathing tube around the sheathed elements is filled with cement mortar. In the anchor regions, the tubular envelope includes an anchor tube enclosing an anchor pot, The anchor pot has a base with openings through which the individual elements pass in a sealed manner. The anchor pot is filled with a corrosion-protection mass. Accordingly, the individual elements are axially movable and retensionable along their entire lengths.
The sheathing ducts and the anchor pot separate the cement mortar from the individual tension elements in the free region extending between the anchor pots.
A corrosion-protected tension member, such as a tendon for prestressed concrete with post-tensioning, is made up of a bundle of individual tension elements, such as strands, ar-ranged within a tubular envelope. The tension member extends between anchoring devices, each forming an anchor region for the tension member with a free region located between the anchor regions. In the free region, the tubular envelope is formed of a sheathing tube. Each individual element is located within a separate sheathing duct, and a corrosion-protection mass fills the space within the ducts about the elements. The open volume within the sheathing tube around the sheathed elements is filled with cement mortar. In the anchor regions, the tubular envelope includes an anchor tube enclosing an anchor pot, The anchor pot has a base with openings through which the individual elements pass in a sealed manner. The anchor pot is filled with a corrosion-protection mass. Accordingly, the individual elements are axially movable and retensionable along their entire lengths.
The sheathing ducts and the anchor pot separate the cement mortar from the individual tension elements in the free region extending between the anchor pots.
Description
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BACKGROUND OF THE INVENTION
The present invention is directed to a tension member protected against corrosion, mainly a tendon for prestressing concrete with post-tensioning. The tension member is formed of at least one tension element, such as a steel rod, wire or strand, located within a tubular envelope with anchoring de-vices arranged at the ends of the tension memberO The tension member extends between anchor regions at the anchoring devices, ,, with a free region extending between the anchor regions. In the free region, the tubular envelope is formed of a sheathing tube and is tlghtly secured to the anchoring devices in the anchor region. Open spaces are provided between the indivi-dual tension elements within the tubular envelope and at least in the region directly adjoining the anchoring devices the l open spaces are filled with a plastically deformable corrosion-protection mass. Further, the invention is directed to a method of installing the tension member in a concrete struc-tural member.
~.1 In structural design, particularly of bridge structures formed~of prestessed concrete, prestressing with pretensioning ¦ ~ and with post-tensioning is known. Prestxessing with ¦ ~pretensioning is performed mainly as prestressing with subsequent pretensioning where the tendons or tension members remain~free to move until the concrete sets and are subse-quently bonded to the structure by injecting grout. In pre-I
li ~3U~
stressing with post-tensioning, the tension members are gener-ally located outside of the concrete structurej though they are supported relative to the structure, they can be inspected at any time,and, if necessary, retensioned or replaced.
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Tension members used as tendons for prestressed concrete with post-tensioning, or as diagonal cables for stayed cable bridges or for the rehabilitation of structural members and other structural tasks, require permanent corrosion protection made up of two independent corrosion protected systems with each system being completely effective by itself. A known tendon of this type, (Dyckerhoff & Widmann Publication "DYWIDAG~-Report", No~ 11, 1982, page 7) is formed of a pre-stressed tendon surrounded by a polyethylene sheathing tube across the free region of the tendon. The annular space be-tween the tendon and the sheathing tube is closed of~ at the ends of the tendon by seals and the annular space can be injected with a hardenable material, such as cement mortar.
Such a hardening material forms the first corrosion protection system across the free reglon of the tendon, the second cor- ¦
rosion protection system is the sheathing tube itself. In the anchor reglons, the sheathing tube is joined with a connecting tube and the connecting tube is joined to the anchoring plate of the anchoring device. To maintain the tendon so that it can be stressed, prestressed or replaced, the corrosion resis-tance in the anchor region is provided by a plastically deformable corrosion-pr~tection mass, such as grease, filled under pressure into the annular space between the tendon and the connecting tube. Accordingly, in the anchor region, the first corrosion protection system is the corrosion protection mass and the second system is formed by the connecting tube joined to the anchoring plate.
With such an arrangement, doubtless there is the advan-tage that the use of a comparatively expensive corrosion protec-tion mass can be limited to the anchor region, while the less expensive cement mortar is utilized for the free region of the tendon which represents a considerably larger volume. There is the disadvanta~e, however, that the cement mortar must be injected prior to the installation of the tendon, since the annular space in the free region of the tendon is not acces-sible after lnstallation because an anchor tube is fixed to the anchoring plate. While this arrangement is acceptable in the case of individual tendons formed of a single tension rod, however, with bundled tendons r it is not acceptable, since the tendons could not be handIed due to the great weight involved.
; 1 Furthermore, segmented fabrlcation of structures, such as the fabrication of bridge structures ln the so-called time-¦ shifting or incremental launching method often necessitates the provision of an addltional tendon for a subsequen-t section to a tendon already anchored to the section, and the connec-tion of such tendons, so that the entire tendon can be ten-sioned from the opposite ends.
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~ ~ -4-For tendons with subsequent pretensioning so-called cou-pling points are known for joining the tendons. Thus, an anchoring and coupling device of one bundled tendon comprises one anchoring member which, in addition to conical bores for ~ prestressed anchoring of the incoming tension members by I means of wedges also has additional conical bores oriented in the opposite direction for anchoring the outgoing tension members (DE-PS 32 2~ 702)o Such bores are arranged uniformly across the surface of the anchoring member. In this anchoring member, cylindrical bores follow the conical bores for anchor-ing the outgoing tensioning members and such bores are filled I !
with a permanently plastic lubricating corrosion protection mass, whereby the tension elements are freely extended across these comparatively short axial dis~ances. By injecting the entire remaining tubular enclosure with hardenable material, such as cement grout, a certain spring action of the tendon is l utilized because of the short bond-free distance of the out-I going tension member, and the danger of crack formation in the coupling joint is reduced.
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., 1 SUMMARY OF THE IN~ENTION
Therefore, it is the primary ob~ect of the present inven-tion to provide a tension member which can be retensioned or replaced, especially a bundled tension member or tendon, where not only different corrosion protection material can be uti- ¦
lized in -the anchor regions and in the free regions of the ~5~
I' ~3~ 5 tension member, rather such materials can be applied indepen-den-tly of each other and without mutual interaction to a struc-; ture. It may even be possible to supply the material afterthe installation of the tension member. In addition, it is ; possible to construct a tension member of two or more axially , extending sections coupled together in a friction locked manner.
',' In accordance with the present invention, each of the tension elements forming the tension member is enclosed in a sheathing duct formed of a plastics material, such as poly-I¦ ethylene and a plastically deformable corrosion protection mass fills the space between each tension element and the ;i . i enclosing sheathing duct. The hollow spaces located between I the individual ducts and the tubular envelope of the entire ! tension member is filled with a hardenable material, such as ! cement mortar, except in the regions directly adjoining the 1~ anchoring devices, into which the ducts of the tension ele-; ments penetrate. This region, adjoining the anchoring device, ~;
is filled with a plastically deformable corrosion protection mass.
Accordingly, the present invention provides a tension member or tendon, especially a bundled tendon, in which individual tension elements, preferably steel wire strands, are enclosed along with entire length, including the anchoring devices, by a plastically deformable corrosion protection mass, whereby the tension elements remain permanently axially !i ',~
' movable and retensionable. By utilizing tension elements, enclosed within polyethylene ducts, as so-called greased ; strands, there is provided a limitation of the space to be ~ filled with the plastically deformable corrosion-protection , ~
mass to the region immediately surrounding the individual tension elements and to the space directly adjoining the anchoring devices. ~he ducts for the tension elements provide a barrier between the corrosion protection mass enclosed in the ducts and surrounding the elements and the outer tubular envelope of the over-all tension member, so that the remaining open space within the tubular envelope can be filled with a hardenable material, such as low-cost cement mortar. Such a hardenable material not only affords a smooth transition at change in direction points during the expansion of the tensionin~ of the tension elements at the anchoring devices and at the change in direction points, but it also affords an additional protection if there is any failure of the grease Forrosion protection.
In accordance wlth the invention, not only is free axial J
mobility of the tension elements~forming the tension member maintained, there is also the advantage of installing such a tension member including its tubular envelope or enclosure with the furthex possibility of removing such a member if the tendon is only~being utilized in the construction of a bridger I but is unnecessary in the finished bridge structure. Moreover, Il such a tendon can be replaced in the structure by another tendon if it were to become damaged. In accordance with the invention, the tubular envelope in the anchoring region is formed of an anchoring tube coopera-ting with an abutment mem-ber so that an anchoring pot can be inserted within the tube leaving an annular space between them. The anchoring pot has a number of openings in its base corresponding to the number of tension elements and, at its end spaced from the base, it has a flange forming an annular space, and the anchoring pot is filled with a plastically deformable corrosion protection mass.
, The abutment member, against which an anchoring disc penetrated by the tension elements comes to rest, includes in an advantageous manner at least one injection and/or venting aperture for the hardenable material being charged into the ! annular space.
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., The anchoring tube inserted into a central opening of the abutment member preferably has a flange abuting against an annular shoulder formed in the opening. An elastic material sealing ring is preferably arranged between the flange of the anchoring tube and the annular shoulder.
~; fl The anchoring tube is provided with spaced protuberances arranged around its circumference at its end against which the ,1 anchoring pot rests. The anchoring disc can be provided with a tubular extension at its side facing the abutment member ,1 !I with the extension passing into the anchoring pot in a tele- ¦
I scoping manner.
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The advantage of the invention is that in the anchor region and particularly in the anchoring pot, there is a cor-rosion protection mass with the anchoring pot being placed in a simple assembly procedure on the tension elements previousl~
inserted and then slipped into the anchoring tube. The an-choring pot, as compared to the anchoring tube, is shaped so that an annular space remains in the region of the abutment memberwhere injection and/or venting lines are provided and which continues around its circumference with an annular space.
The annular space affords a connection to the hollow space in the free region of the tension member outside the anchoring pot, so that it can be injected with a hardenable material, pre~erably cement mortar. Preferably, the anchoring pot prevents the material from penetrating into the anchor region and fixes the anchoring means, such as anchoring wedges. ' ~.
The ducts enclosing the individual tension elements ex-tend into the anchoring pot filled with corrosion protection mass and thus assure complete corroslon protection.
1 ~Additlonal advantages follow from the loose connection fl between the anchoring tube and the abutment member, in that the anchoring tube lS provided with a flange at its end ex-posed to the atmosphere and can be pushed through the central l opening of the abutment member, where it comes into contact with an annular shoulderO This simplifies the assembly, and, in addition, affords compelsation fcr angular differences _9_ 1, ~
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between the anchoring tube contacting the tension elements and the abutment member, particularly if an elastic material seal-ing ring is positioned between the flange of the anchoring tube and the annular shoulder. The tubular extension on the anchoring disc facilitates the installation by engaging within the anchoring pot and assuring a self-centering action.
The anchoring tube widens toward the anchoring device in a trumpet-like manner. An intermediate layer of an elastically and/or plastically deformable material, such as a plastics material, can be located between at least the outer tension ` elements and the inner surface of the anchoring tube for af-fording a smooth transition of change in direction forces.
The intermediate layer can be in the form of a ring in contact with the inside surface of the anchoring tube. In place of I the intermediate layer, the outer tension elements can be I conducted through a plastics material sheathing tubeO
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If comparatively short tension elements are used, the length of the anchoring pot is selected so that the ends of the plastics material sheathing ducts do not become displaced from the anchoring pot if changes in length of the plastics material sheathing ducts is caused by temperature differences.
If comparatively long tension elements are employed, the plastics material sheathing ducts can be prevented from sliding out of the anchoring pot by providin~ an enlargement around their circumferences.
!l ,, The anchoring tube is appropriately connected with the tubular envelope in the free region of the tension member in a tension-proof manner.
An expansion joint can be provided along the tension member to compensa-te for changes in length due to temperature differences. At the expansion joint, the tubular envelope is b~tt-jointed and the joint is tightly overlapped by an outer sleeve connected with a portion of the tubular envelope.
The hardenable material which fills the space outwardly of the individual sheathing ducts on the tension elements and the tubular envelope can be provided with reinforcement to avoid cracks.
To construct such a tension member or tendon in series from two or more axially extending sections, at least one of the anchoring devices can be constructed as a coupling member with the preferably circular anchoring disc abutted against the abutment member having bores for anchoring the incoming tension elements and additional bores for anchoring the out-going tension elements. In addition, a sealing disc closes off the hollow spaces formed about the tubular ducts and is provided with opening for at least the outgoing tension ele-ments and is arranged in the region of the outgoing tension elements spaced from the anchoring disc~ The hollow space located between the sealin~ disc and the anchoring device is .1 ~I
., I, --1 1--filled with a plastically deformable corrosion-protection ; mass, for instance greaseO
Accordingly, it is possible to use such a tension member as a tendon for prestressed concrete with post-tensioning in structures to be constructed in sections, such as construction ~` by incremental launching method type bridges.
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The tubular envelope about the outgoing tension elements, in the region adjacent to the anchoring device is in the form of a casing, for instance, formed of metal, which can be connected in a sealed, as well as pressure and tension-proof '~
manner. Further, it is detachable from the anchoring device and the tubular envelope in the free region of the tension member.
After the expansion of the outgoing tension elements towards the anchoring disc, the casing can be formed of a number of sections of different diameters and, further, can be made up of parts separate from one another in the sections of , different diameters. Such parts are preferably displaceable with respect to one another in a telescoping manner and are detachably connected to one anotherO
Expediently, the sealing disc is located at a transition point between two sec-tions of the casing with different diam-eters and the sealing disc can be detachably connected to the casing.
It is also possible to arrange the sealing disc as a spacer for the tension elements and for carrying change in direction forces oriented radially inwardly and caused by the increased spacing of the tension elementsO The sealing disc is formed of two plates pressed against one another with seal-ing rings interposed between them and surrounding the tension elements where they pass through the plates.
;'` ', A redirecting member laterally encircling the bundle of ~! tension elements in an annular manner is arranged for carrying the change in direction forces oriented radially outwardly at the beginning of the spreading or further spacing apart of the tension elements. This redirection member is located inside the tubular enclosure or envelope and is detachably connected with it.
l l l ,!
~ l~The tubular envelope,enclosing the tension elements in il i the free region of the tension member,extends into the redirec-tion member forming an intermediate layer between the tension ~ elements and -the redirection member. -I To arrange the outgoing tension elements in an orderly i manner, an expansion ring, preferably formed of plastics mate-rial, is located in the region of the redirection member. At its outer circumference, the ring has receptacles for fixing ¦¦ the tension elements individually or in groups. These recept-~l acles can be formed as radiaI websO Further, the expansion :
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., li -13-, I
I
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ring can be constructed as a sealing disc. Where a tendon is post-tensioned, and is located outside of the concrete cross-section of a structural member, it is impossible, as a rule, to adapt the axis of the tendon or tension member to the course of the bending moments in a continuously curved manner.
Generally, it is necessary to guide the tension member approximately at a multi-sided train.
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As a result, change in direction points are formed where forces oriented toward the inside of the curve have to be carried. In the region of these change in direction points, the tubular envelope is conducted, in accordance with the invention, along a circular arc, to aEford a smooth transition of the change in direction forces. By axially mobile guidance of the tubular envelope at these change in direction points, 1¦ it is possible to make the tension member removable, if it is necessary to replace it. Spacers are located in these change in direction regions with the spacer forminy openings to which .
the tension elements pass~ ~
I
It is important in the method of installing such a ten-sion member that the hollow space between the encased tension elements and the tubular envelope is filled with a hardenable material at least in the region of the change in direction before the tension member is stressed, so that the change in direction forces can be carried with a smooth transition. The ¦
axial mobility of the tensLon element with respect to the structure is, as a rule, also maintained in the region of the '~ "
! -14-change in direction points. If differential forces are to be applied at the change in direction points, then a bonding between the tension elements and the structure must be pro-duced. Such a bonding can be effected in a known manner.
, , The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described pre~erred embodiments of the invention.
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DESCRIPTION OF THE DRAWINGS
In the drawings:
Figure l is an axially extending view, partly in section, of a bridge support structure using tension members, in accordance with the present invention, as tendons with j post-tensioning, with the view taken along line I-I in Figure Figure 2 is a transverse cross-sectional view through the bridge structure taken along the line II-II in Figure l;
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Figure 3 is an enlarged view of an anchoring region in the bridge support structure;
Figure 4 is an axially extending sectional view of , an anchoring and coupling region of the tension member embodying the present invention and corresponding to Figure 3;
, Figure 5 is a view, partly in axial section, and partly in side view, on an enlarged scale, as compared to : ~I Figures 3 and 4, illustrating the anchorlng region of a l¦ tension member embodying the present invention;
: Figure 6 is a transverse sectional view, taken along the line VI-VI in Figure 5;
Figure 7 is an enlarged partial view of a portion of 'I
the anchoring region in Pigure 5, and displayed on an enlarged scale;
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Pigure 8 is a exploded view of an anchoring region for the tensIon~member of the present invention, and displayed Y in section;
j Figure 9 is a partial axially extending section llustrating another embodiment of the anchoring region of a ll tension member, in~accordance~with the present invention;
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~1 Figure 10 is a vlew in axial section of the anchor-ing region of a tension member illustrating another embodiment of the present invention;
,, Figure 11 is a a view similar to Figure 10 of still another embodiment of the anchoring region of a tension member in accordance with the present invention;
, Figure 12 is a partial axial view through an anchor-I ,l ing pot for fixing the sheathing duct of a tension element;
1, .
Figure 13 is a transverse sectional view taken along .
the line XIII-XIII in Figure 12; - ' ., I
Figure 14 is a schematic showing o an expansion joint in the tubular envelope for the tension member;
Figure 15 displays a partial axial section of an anchoring and coupling region for a tension member embodying the present invention and set forth on an enlarged scale;
: ~ :5 : : ~
Figure 16 is a partial axially extending section ~5 ~ through an anchoring device with an anchoring disc;
Figure 17 is a partlal axially extending section ',i thr~ough a sealing dlsc in the region of the outgoing tension 1~ elements;
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Figures 18a and 18b are, partial axially extending sections, at the end of the tension element widening region of the outgoing tension elements;
Figure 19 is a partial transverse sectional view through the outgoing tension elements shown in Figures 18a and 18b;
, Figure 20 is a partial axially extending section through an anchoring device embodying the present invention and including another embodiment of an anchoring disc;
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'. Figure 21 is an enlarged sectional view of a portion "
Il of the anchoring device as shown in Figure 20; and ,1 , j Figure 22 is an axially extending view of a change ' in direction point of a tenslon memher embodying the present :~ invention shown partially in axially extending section and !
~' partially in side view.
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1, , -18-., '1 130~;S
DETAILED DESCRIPTION OF PREFERRED
EMBODIMENTS OF THE PRESENT INVENTION
_ _ . . . . _ .
In Figures 1 and 2, a bridge deck or roadway 1 is illustrated with a closed trapezordally-shaped cross-section and the roadway is produced by the known incremental launching method. The bridge deck is formed of two elongated inclined girder webs 2, joined at their lower ends by a horizontal base plate 3, and at their upper end by a deck plate 4, extending between the upper ends of the webs and continued laterally outwaardly from the webs by cantilevered sections 5.
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The bridge deck 1 is prestressed by tension members or tendons with post-tensioning. In Figure 1, which is not to scale, an axially extending section is provided and illustrates schematically one axially extending section of the bridge deck ; I 1, between a fixed support 6, and a movable support 7, with the tension member 10 provided with an axis 11. In accordance with the characteristic of a continuous girder, the tension axls 11 shown in the cross-sect1on of Figure ~, is located in i the upper part of the cross-section and in another part of the axial section in its lower region, not shown. Within the deck 1: ~ 1 ~ cross-section, the tendons are located passing through the l1 side pilaster members 8, where they are anchored and possibly o~erlap, as well as in the region of the pilaster members 9, in which the tendons undergo~a change in direction, that is, t hey represent change in direction points. The pilaster li members 8, 9 extend inwardly from the inside surfaces of the ~' legs 2.
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130~lS~
An anchor region of the tension member 10 is displayed on a larger scale in Figure 3, shown partially in axial section and partially in side viewD The tension member 10 is made up of a bundle of tension elements, for instance strands 12 of steel wire, each enclosed within a casing or sheathing duct 13 for corrosion protection. The hollow space within the sheathing ducts 13, around the strands, is filled with a plastically deformable corrosion protection mass, such as grease. The strands or tension elements 12, located within the sheathing ducts 13 are enclosed within an axially ex-tending tubular envelope 1~. The tendon 10 abuts against a piIaster member 8 by means of an anchorage device 15.
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Tubular envelope 14 in the normal or free region A of the tension member 12 is a plastics material sheathing tube, for instance, polyethylene, connected adjacent to the anchorage device 15 to a cast iron anchoring tube 17, with the tube widenlng in a tru~pet-like manner toward the anchorage device 15~ In the adjacent region B, forming a part of the anchor region, the spacing of the tension elements is increased towards an anchoring disc 18 for effecting the anchorage of the elements, that is, the over-all transverse cross-section of the tension member 10, formed by the elements 12, increases from the region A toward the anchorage. The anchoring disc 18 "
abuts against an abutment plate l9 bearin~ a~ainst one side o~ i the pilaster member 8, this region is designated as region C
forming part of the anchoring region.
1 !
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The tension elements within the region B pass through the base plate of an anchoring pot 20, located within the anchor-ing tube 17 in a sealed manner. The anchoring pot is filled with a plastically deformable corrosion-protection material 21, such as grease. Note, in Figures 3 and 4, the regions I, II located above the anchorage. The region I extends from the anchoring disc to the base plate of the anchoring pot. In the region I, the tension elements 12 are axially movable in the corrosion protection mass 21 and in the outer region II, extending away from the anchoring pot are axially movable within the sheathing ducts 13. Externally of the anchoring pot 20 and in the region II, the hollow space or volume between the sheathing ducts 13 and the sheathing tube are envelope 16, is pressure injected with a hardenable material '~ 22, for instance, cement mortar.
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The anchor region of the bundled tension member 10, shown only generally in Figure 3, is displayed on a larger scale in Figures 5 to 7. Tension elements 12 are anchored in conical bores 24 within the anchoring disc by means of multipart tapered collars or wedges 23. Anchorlng disc 18 abuts via shims 25 against an abutment plate 19, and the abutment plate I ! bears against the outside surface of the pilaster member 8, as !
shown in Figure 5, or it can also be embedded in the pilaster ,I member. Abutment plate 19 includes an axially extending ll tubular section 26 extends into a tubular recess 127 with a !' slightly larger diameter than the tubular section with a ~ -21 'i 1 .~ ~3(~355 recess 28 extending through the pilaster member and forming an opening through which the tension member 10 passes. Sheathing tube 16 is connected to the anchoring tube 17 adjacent to the anchorage, leaving an intermediate space. In the structure illustrated in Figure 5, the connection between the tubes 16 I and 17 is in the form of a butt joint made up of a sleeve 29, for instance, formed of plastics material, encircling the ends of the sheathing tube 16 and the anchoring tube 17, adjacent to one another, with the sleeve 29 fastened in place by clamps, such as hose connectors 30. ~.
''' Anchoring tube 17 is formed of cast iron and thus is able to carry the change in direction forces generated by the widen--ing of the spaces between the individual tension elements and passes through a opening in the abutment plate 19. In the detail in Figure 7, anchoring tube 17 includes an outwardly bent flange 32 at its end, adjacent the anchorage, and the flange rests agai.nst an annular shoulder 34 in the abutment plate with the interposition of a sealing ring~33 made of an elastic material, for instance, rubber, with the annular shoulder narrowin~ the central opening 31 at the side of the abutment plate facing toward the anchoring pot 20. At its end, within the opening 31 in the abutment plate 19, the anchoring tube 17 is provided with protuberances 35 uniformly spaced in the circumferential direction with the protuberances extendlng radially outwardly, and also in the axial direction beyond the flange 32 toward the anchoring disc 18.
1, ~ -22-~3()~8SS
As displayed best in Fiyure 8, an anchoring pot 20 is inserted into the anchoring tube 17 and has an outside dia-meter at this location somewhat smaller than the inside di-ameter of the anchoring tube 17. Anchoring po-t 20 is centered in the anchoring tube 17 by the radially inner portion of the protruberances 35, and is maintained from the inner surface of the anchorin~ tube so that an ann~lar gap or space 36, note Fi$ure 5, is located between them. The anchoring pot 20 has a ~ottom or base 37 at its end more~ remote from the anchoring disc 1~ and the base has a number of openings 38 so tha-t the :i! !
teDsion e1ements 12, along with ~heir sheat~ing ducts 13 can pass throug~ the openings. A tubular exte~sion 18a on the anchoringi disc 18, extends into the ancho~.ing pot in the re~ion of the abutment plate 1~ and provicles a cen~ering a~tion ~or the anchoring disc~
Anch~ring pot 20 has a flange 39 a~ its end, closer to the anchoring disc 18, note Figure 7, and the flange contacts ' the protuberances 35 on the flange 32 o the anchoring tube, that is the ends of the pro~uberances.facing toward the anchor~
in~ dlsc 18. As a result~:an annular space 40 is provided in the region of the abutment plate 19, limited inwardly by the an~h~.~ri~ ~ot 20, and radially outwardly by the surface of the ~i!' o~in~ 31 in the abutment p~ate 19, and on the opposite sides . are th2 ~lla~ges 32 and 39 of the anchorin~ tube 17 and the : 1` ah~horing p~t 20. Several in¦ection aper~ures 41 extend into ~l the ~nnul~r -space 40 and pass through the ~butment plate 19, .
`- ` 13~
note Figures 5 and 7. Annular space 40 is in flow communi-cation with the inner hollow space within the sheathing tube 16, via the annular gap or space 36, between the anchoring pot 20 and the anchoring tube 17, so that the hollow space can be ; injected with hardenable material, for instance, cement mortar through the injection apertures 41, and a corresponding ~ venting opening provided at the opposite anchorage.
I ~ From Figure 5, it can be noted how the hollow space with-in the anchoring pot 20 is filled with a plastic corrosion-protection mass, such as grease, which assures the corrosion-protection in the region of the anchorage and permits subse-quent detachment of the wedges 23 for retensioning or loosen-ing the tension on the tension member 10 in order to replace it. Shims 25 also serve in reducing the tension. The cor-,1 ~
rosion-protection mass 21 has direct connection in the region ~ of the anchoring pot 20 to the corresponding corrosion-I protection mass within the sheathing ducts 13 enclosing thetension elements 12. The hollow space remaining between the sheathing ducts 13 and the inner surface of the over-all sheathing tube 16 can be injected through the annular space 40 ¦ and the annular gaps 46 with a hardenable corrosion-protection material 22, for instance cement mortar, which passes over the a~choring pot 20, filled with grease.
!l I
i The condition in the region where the space between the tension elements is increased in the anchoring tube 17 is ~ .
~``` 1;~0~)~5~
explained in detail with the aid of Figures g, 10 and 11. At this location, it is necessary to redirect at least the ten-sion elements located in the radially outer part of the bundle in a smooth transition and to guide them so that their metallic surface does not slide on the inner metallic surface of the anchoring tube during the tensioning step which interaction could cause frictional corrosion. Accordingly, as shown in Figure 9, a ring 44 of a plastics material, for instance, polyethylene, is located in the portion of the anchoring tube where the increase in the spacing of the tension elements is commenced, note Figure 9. Ring 44 is inserted into a widened portion in the wall of the anchoring tube forming a seat in the inside surface of the tube so that the ring projects in-wardly from the inside surface and thus assures a smooth guid-ance of the tension elements in this region and a smooth transi-tion of the redirection forces.
' A similar efect can be achieved, as shown in Figure 10, if the radially outer tension elements in the bundle are pro-vided with sleeves 47 of plastics material. Further, Figure . . , ~ 10 shows a connection between the anchoring tube 17 and the li ~ .
sheathing tube 16' in the free region of the tension member ¦ 10, that is, between and spaced from the anchoragesO It is expedient in certain cases to form a solid connection between the~two tubes forming the tubular envelope for the tension member. The connection can be achieved by providing the , .
anchoring tube 17' and the sheathing tube 16' with flanges .1 1 18, 49, respectively, with the flanges connected in a tension-proof manner by screws 500 Ano~her embodiment for ~he connection of the sheathing tube to the anchoring tube in the free region of the tension member is i.llustrated in Figure 11. Similar to the embodiment in Figure 10, the anchoring tube 17'l has a outwardly directed flange 48 at one end, the sheathing tube 16 " is welded at its adjacent end by a welding seam 51, with an intermediate piece 52 of approximately T-shaped cross-section of the same mate-rial as the sheathing tube 16 " ~ At the opposite end of the tubular inner portion of the intermediate piece 52, an axially extending tubular section 54 is secured by a welding seam 53 at the beginning of the trumpet-like expansion of the anchor-ing tube 17 " with its smooth lining affording support for the radially outer individual tension elements 12. In this embodi-ment, the sheathing tube 16'' with the i.ntermediate piece 52 is lengthened for extending into the anchoring tube 17'' af-fording a continuous support for t~e individual tension ele-ments 12 in this critical region. The radially projecting part of the intermediate piece bears against the flange 48 on the adjacent end of the anchoring tube 17 " , and is secured to the flange by a ring 54' and bolts 50.
In view of this connection, to avoid excessive tension forces in the sheathing tube 16, caused by temperature differ-ences, an expansion joint 55 can be provided at any point along the tension member 10, note Figure 14. Since the external corrosion-protection system, that is, the tubular ., ~
; -26-, I
:IL30~S~
envelope for sheathing tube 16, is interrupted at the expan-sion joint, a leak-proof connection is provided. This feature is indicated in the illustrated embodiment by an inner tube 56 and an external tube 57, which is fastened at one end by a welding seam 58 and is sealed at its other end against the outside surface of the tubular envelope by sealing rings 59.
When using the tension elements 12 with their sheathing ducts 13, according to the invention, attention must be paid to the fact, in changes of length in the sheathing ducts 13, due to temperature differences to which the tension member 10 is exposed, since i~ is not concreted into the structure, that the she~thing ducts do not slide out of the anchoring pot 20 filled with the corrosion-protection mass 22. In the case of short tendons where only minor changes in length occur, the axial length of the anchoring pot can be such that changes in length of the sheathing ducts 13 occurs within the limits of the actual length of the pot. With longer tension membersr it . .
is necessary to prevent extensive changes in the length of the i sheathing ducts 13. This can be accomplished in a simple manner by fastening the ends of the sheathing ducts 13 within the anchoring pot 20 so that they cannot slide through the '.l opening 38 in the base 37 of the anchoring pot 20. This can ~I be achieved in various ways, some of whlch are illustrated in Figure 10, as well as in Figures 12 and 13. A clampin~ sleeve 60, formed of a plastics material, is placed at the end of the ¦ sheathiny duct 13 on a tension element 12, and the clamping .
''I I
'` ;
~3C~3;,5 sleeve is provided with a axially extending slot 61 and with ribs in its inside surface, that is, with an internal thread affording a friction and/or positive locking connection with the sheathing duct 13. A similar effect can be attained with ~, I
hose clamps, tapered sleeves, or the like.
l, The assembly of the anchoring device described above is as follows: Initially, an abutment plate l9 is enclosed in concrete within a structural member, for instance, the pilaster member 8, shown in Figure 3, in such a way that its axially extending tension tube 26, together with the tubular recess 27, forms an opening 28 for the tension member lO. After placement of the sheathing tube 16, which may be made up of several axially extending sections, if, as shown in Figure l, change in direction points are present, the anchoring tube 17, with the sealing ring 33, is provided at both ends and is connected to the sheathing tube 16. For axial mobility during assembly, the final connection occurs only at the anchoring end.
Next, tension elements 12, provided at both ends with ~ , numbered tags for identification, are slid from a coil into the sheathing tube 16 by a sliding-in device, not shown. When aIl of the tension elements have been inserted, an anchoring pot 20 is pushed on each of the ends of the tension member lO.
Care must be taken that the numbered tension elements 12 reach corresponding openings 38 in the base 37 of the anchoring pots 20 at the opposite ends of the tension elements. The openings 38 are sealed to a degree by the sheathing ducts 13. Next, ~ ~3~3~55 the sheathing ducts 13 on the tension elements 12, in the anchor region, can be removed and the anchoring pot filled with the pasty corrosion-protection mass 21, if it has not already been filled prior to this timeO
A spacer 42 is then slid onto the tension elements 12, whereby the spacer prevents direct contact of the tension elements 12 with the anchoring disc 18, note Figure 5, and maintains the parallel guidance of the tension elements, so that there is no reduction in the vibration strength. Subse-i, quently, the anchoring disc 18 with its tubular extension 18a ~!
and the shims 25 are slipped on the ends of the tension ele-ments and the corrosion-protection mass 21 is further compac-ted. Accordingly, the tubular extension 18a affords a self-centering of the anchoring disc 18, while being slipped into the anchoring tube 17, note Figure 8. Finally, the annular ` wedges 23 are inserted into the conical bores 24 in the anchoring disc 18.
., !
Subsequently, it is helpful to stretch the tension ele-ments 12 individually with a light duty hydraulic press, prior to tens1oning all of the tension elements -together with a ¦ bundle tensioning press or jack. If necessary, the portions of the tension elements extending beyond the anchorage are cut off and a corrosion-protection mass is injected with the help of a grease gun through hores in the anchoring disc 180 For positive corrosion protection of the anchorage, a protective ~1 1 - - \
~3~855 .
covering is placed over the ends of the tension elements pro-jecting outwardly from the anchorage and the cover is filled with a corrosion-protection mass 21, note Figure 5. Where-upon, the posi-tive connection of the casin~ with the anchorage .; and the connection of the sheathing tube 16 with the anchoring tube 17 can be effected and, finally, the hollow volume re-maining within the free reyion of the sheathing tube 16 can be pressure-injected in the described manner through the injec- ;
` tion openings 41 with a hardenable material, such as cement mortar.
. I I
To prevent cracks in the hardened cement mortar as a result of length changes of the tensi.on member 10 due to temperature differences, since the cement mortar does not bond with the tension elements 12 or the sheathing tube 16, the cement mortar should be reinforced. Reinforcement can be j provided by using grout in which glass fibers or the like have been added or into which one or more steel wires as reinforce-ment of the mortar along with the tension elements 12 within the sheathing -tube 16.
il , In Figure 4 and in Figures lS to 21, an anchorage or anchor point acting also as a coupling point is shown. In Figure 4, such a combination is shown partly in axial section I and partly in side view. Basically, the tension member 10 is : designed in the same manner as shown in Figures 3 and 5. In this case, however, the tension member abuts only by means of I
~1 ~, , -30-~ ` 13(~
the anchoring device 15', used only as an intermediate anchor-age, against the pilaster member 8, forming part of a construc-tion member, and is continued in the direction away from the pilaster member from the anchoring device 15' up to the next anchoring device designed as an end anchorage in accordance with Figures 3 and 5. The portion of the over-all tension :1 .
member 10 to the right of the anchoring device 15' in Figure 4 is designated as the "incoming" portion 107, while the portion to the left of the anchoring device 15' in the Figure is desi~-nated as the "outgoing" portion 10''.
The tubular envelope in the combined anchoring and cou-pling region C and in the adjacent region D of the outgoing portion 10'' of the tension member 10 is formed by a casing 70 designed differently as a function of the lateral spreading of the tension elements 12''. Primarily, the casing 70 is formed of metal, however, it can be made of plastics material, such as polyethylene. In Figure 4, the casing 70 consists of two consecutive axially extending sections with stepped diameters fl affording a transition to the normal or free region E corre-sponding to the normal or free region A, where it is connected : 1,l to a sheathing tube 16 made of plastics material, for instance, polyethylene. The casing serves not only for mechanical and corrosion protection of the coupling point, but also for secur- ' ing a redirection member 71. If it is formed as a metal tube, it can also be used for the reduction of the bending mom~nts.
Tension elements 12, enclosed by sheathing ducts 13, l~ iormed of polyethylene in the axially extending normal regions il i I
13~ tii-3 A and E, as well as in the regions B and C, where the spacing of the elements is varied, and or guided within the anchoring tube 17 through the base 37 of the anchor pot 20 in a sealed manner and on the opposite side of the anchoring de~ice are guided in a sealed manner through a sealing washer 72. The base 37 and the sealing washer 72 form the axial bounds of the ~, .
region I, note Figure ~, of the tension member 10, in which the hollow space within the tubular envelope is ~illed with a plastically deformable corrosion-protection mass 21, for in-stance, grease, and in the remaining regions II on the op-posite sides of the region I, of the tension member 10, the exterior of the anchoring pot 20, is pressure injected with hardenable material, such as cement mortar 22. The tension elements 12 are guided for axial mobillty over the full length of the tension member 10 and are coupled in an overlapping manner in the region I adjacent the anchoring device 15 and filled with a corrosion-protection mass so that the tendon ~j member 10 made up of several axially-extending portions 10', , 10l' can be tensioned from the ends.
i ¦ The outgoing portion lO ":of the tendon is shown at a larger scale in partial axial cross-section in Figure 15 ~ith ¦! the essential parts illustrated in detail in Figure 16, 17 and 18.
l ll As can be determined from Figure 16, the incoming tension ¦
elements 12', note Figure 4, are kept in order in the region f' -32- ~
- ~ ~L3~
of -the abutment member 19 by a spacer 42 and pass through bores 73 in the anchoring disc 18' and are anchored by wedges 23 extending into the frusto-conical ends of the bores. The ends 74 of the tension élements 12' extend for a length beyond the anchoring disc 18' corresponding to the strain, so that it is possible to remove the tension from the entire tension memher or tendon. The anchoring disc 18' abuts against shim 75 and presses an intermediate ring 76 against the abutment plate or member 19.~ Anchoring disc 18' is centered within a central opening in the abutment member 19 by an extension tube 18a'. While the incoming tension elements 12' are anchored in the central region of the anchoring disc 18', the outgoing tension elements 12'' are anchored in the radially outer re~ion of the anchoring disc outwardly from the incoming tension elements 12'. Accordingly, the tension elements can be placed more easily in the required order. Moreover, the outgoing tension elements 12'l are accessible from the outside in the bores 78 so that the wedges 23 can be inserted in place.
To return the tension elements 12''j shown in parallel, from the position in the anchoring disc 187 to the spacing in the normal region E, a double change in direction is required, note Figure 15. The first change in direction of the tension element guided in a parallel member in the anchoring disc towards the inside, takes place in the region of the sealing washer 72 which is arranged so that it can carry the change in d.irection forces oriented inwardly. The second change in ~o~s~
direction of the tension elements 12'' takes place in the region of the redirection member 71 which must be able to carry the outwardly directed change in direction forces as annular tension forces. This, which is possible, the tension elements 12'' extending obliquely outward in the direction of their increased spacing, are anchored in appropriately oriented bores in the anchor ring disc 187, then it is not necessary to provide a change in direction in the region of the sealing washer 72~
Casing 70 forms the tubular enclosure 14 of the tension member 10 in the region C of the coupling and in the region D
where the spacing of the tension elements changes from the enlarged cross-section to the normal cross-section. Casing 70 is made up of two axially extending parts with different di-ameters 70a and 70b, note Figures 16 - 18. The larger diameter section 70a, has an outwardly bent flange 79 fastened by means of bolts 80 to the abutment member 19~ note Figure 16. At its opposite end, the section 70a has an inwardly bent flange 81 connected by means of bolts 83 with the adjacent smaller di-ameter section 70b, overlapping the flange 82, extending out-wardly from the adjacent section 70b. Section 70b, note Figure 18a, has an inwardly extending flange 84 to which a connection is made by bolts 85 between the sheathing tube 16 n the free region of the tension member 10 and the redirec-tion or change in directlon member 710 The two consecutive axlally extending sections 70a, 70b o:f the casing 70, are longitudinally displaceable in a telescopic manner relative to one another and to the adjacent sheathing tube 16, . 34-_~ ~3Q(~SS
as is appropriate during installation and disassembly or dur-ing removal of tension on the individual tension elements of the tension member 10.
, ~ The sealing washer 72 is formed of two plates 72a, 72b, Z note Figure 17, provided with registered bores for the passage of the tension elements 12. Outer plate 72b, more remote from the anchoring disc 18', is somewhat thicker in the embodiment 1l as shown so as to carry the change in direction forces. At the inner side of the washer 72, the bores are provided with stepped diameters, and sealing rings 87 are inserted into the increased diameter parts encircling one-bare tension element 12' or a strand with a sheathing duct 13, whereby the sealing ' rings rest in a leak-proof manner against the tension element I or are deformed so as to form a seal by pressing on the inner plate 72a by one or more bolts 88.
. . .
The redirection member 71 effecting the change in direc-tion of the tension elements 12 " in the outward direction consists in the embodiment of Figure 18a of a tubular section and while forming a contact surface for the tension elements 12' widens in a trumpet-like manner with a defined unwinding radius and has at its outer end an outwardly directed flange 90 drilled in the same manner as the flange 84 for receiving the bolts 85. In the embodiment of Figure 18b, the redirec-I tlon member 71' is formed of a solid annularly-shaped molded member 91 of greater thickness than the redirection member 71.
I
13~ r;~
The redirection member 71' has an appropriately curved radi-ally inner surface 92, and has threaded bores in its end sur-face facing the flange 84 for receiving attachment bolts 93.
To fasten the tension elements 12' in position until they are tensioned, an expansion ring 94 made of a plastics material is inserted inwardly of the redirection member 71 or 71'.
'.
Expansion ring 94 is shown in partial transverse section in Figure 19 and serves at the same time for arranging the tension elements 12'' in an a.nnularly-shaped order. Ac-cordingly, a number of receptacles or open spaces 95 are provided around the outer circumference of the expansion ring 94 with the individual receptacles spaced apart by radially I projecting webs 96. I
;, i In the installation or assembly of a tension member 10 with increased length due to the coupling point, the incoming , tension elements 12' are anchored after tensioning in the anchoring disc 18' as previously described. The anchoring i disc 18' abuts against the abutment member 19 through shims 75 ¦ and the intermediate ring 76 used for diameter equalization.
~ j! :Shims 75 are divided into two or more parts so that they can : ll be~removed later if tension is to be removed from the tension member. Intermediate ring 76 can be fastened by bolting it to i the abutment member 19.
,1 'I The two axially extending sections 7Oa, 7Ob of the casing 70 are fabricated separately and initially are slid over the Il sheathing tube 16 which has been readied for installation, prior to weldlng the flange g7 and part 98 continuing the sheathing tube at its end by means of a butt weld.
.' The redirection member 71 is then slipped onto the part 98, note Figures 18a, 18b. Next, the outgoing tension ele-ments 12' are placed into the sheathing tube 16 in the direc-tion of the anchoring device 15 and the sheathing ducts 13 are ~. ~
stripped from the ends of the tension element for approxi-mating the thickness of the anchoring disc 18'. The tubular part 98 continuing the sheathing tube 16, serves as an inter-mediate layer during the tensioning of the tension elements 12', to prevent metal-to-metal contact between the tension element and the redirec1-ion number 71. The tubular section 98 is deformed to conform with the change in direction of the "
' tension elements 12''.
.
Thereupon, the sealing washer 72 is installed. In this operation, the outer plate 72b is slid on and the sealing rings 87 are threaded on~ note F1gure 17. Next, the inner ,¦ plate 72a is posit~ioned and both plates are aligned relative to one another and are connected to one another by the bolts 88.~ As a result, the sealing rings are compressed and the ~, .
sealing force is activated. In the next operation, the Z
sections 70a, 70b of the casing 70 are displaced in a tele-scoping manner toward the anchoring device 15' and are bolted to the abutment member 19 and to the sealing washer 7~, as i 1 i1 :
' ~ 1i 3~
well as with the redirection member 71. At the same time, the sheathing tube 16 is fastened to the anchoring device 15' by positioning the flange 97 between the flanges on the portion 70b and the redi.rection member 71.
Before or only after tensioning of the tension elements 12', the corrosion-protection mass 21 is pressure injected into the region of the coupling point, and hardenable material 22, such as cement paste, is pressure injected into the .
remaining regions. Accordingly, injection tubes 99 are provided in the casing 70 and injection openings 41 in the abutment member 19, note Figure 16. The projecting ends 74 o the incoming tension elements 12' are protected by poIyethylene tubes inserted on them, note Figure 16.
~ I
"
If tension is to be released from the tension number 10, then the procedure above is reversed, starting with the out-, going tension elements 12 " and following with the incoming.
I tension elements 12' being relieved of tension. If only a partial release of tension is to be effected in the individual sections 10' or 10'' of the tension member 10, then only that section 70a of the casing 70 is displaced until the anchoring disc 18' is accessible, then the section 10 " of the tension member 10 is tensioned to the extent that the intermediate rlng 76 lifts off the abutment member 19 and the shim 75 can be removed. After renewed relaxation of the anchoring disc 18' upon the intermediate ring 76, the elongation is reduced. I
~l I
~ ' ~- -38-lil 3()~5~
by the thickness of the shims and with this also the tension force. A possible displacement of the end of the sheathing tube 16 in carrying out this procedure can be prevented, for instance by providing support against the abutment member.
~' .
i :
Another embodiment of the anchoring disc is displayed in Figures 20 and 21 which affords the possibility for placement of the anchoring disc against the abutment member 19 without the use of an intermediate ring 76.
. ~
The bores 73 for anchoring the tension elements 12' in the anchoring disc 18 " by means of the wedges 23 are arranged in the same manner as in the anchoring disc 18' as previously described. The anchoring disc 18 has an increased thickness in the region of the bores 78 for anchoring the outgoing ten-sion elements 12' by means of the wedges 23 so that a support surface 100 is formed with which the radially outer part of the anchoring disc 18l' abuts against the abutment member 19 , . , with the interposition of the shims 75 pro~ided for the possible release of the tension~
~1 !
In this embodiment, since the anchoring points for the ; outgoing tension elements 127 1 are no longer accessible after 1, the installatlon of the anchoring disc 18'' and the tensioning of the incoming tension elements 12l, it must be possible to i !
subsequently insert the outgoing tension elements 12l and to anchor them securely.- Accordingly~ the bores 78 are extended 1l !
Il from the frusto-conical section, arranged for the insertion of ~
- ~',,1 ~i -39-l~V~)~5~
; the wedges, toward the abutment number 19, by a cylindically-shaped widened section 101 in which a pressure spring 102 is arranged bearing against the surfaces of the wedges. A sleeve 103 bears against the free end of the pressure spring 102 and 1~ !
this sleeve is held in place by a snap ring 104 insertable i into an annular groove 105, note Figure 21. In this manner, the wedges 23 can be fastened in position.
When a tension element 12 " is being inserted, the pres-sure spring 102, can be compressed somewhat so that the wedges can be opened permitting the tension elements to pass through them. It is, however, assured by the pressure spring that the inserted strand is securely held by the wedge to prevent any retreating motion. The space formed by the widened section 101 of the bore 78 is filled with the corrosion-protection mass, the corrosion-protection mass 21 can be subsequently injected through a tubular opening 106 accessible on the out-side of the anchoring disc 18'.
'. I
il If, as indicated ln Figure 1, a tension member 10 runs along a path with a number of changes in direction points, then apart from the anchoring regions, the change in direction regions are designed in~ a specific manner so that a smooth ~: i transition of the change in direction forces is effected. One I I ' embodiment for such a change in direction point is illustrated i4 F~igure 22, partly ln axial section and partly in side view.
The tubular envelope for the tension member 10 in the region of the change in direction point is formed by the con-~3~
tlnuously pre-bent steel tube 110, preferably in the shape of a circular arc, which is capable of transferring the change in direction fcrces at the inner side of the curvature to the structural member, in Figure 22, the pilaster member 8. Steel tube 110 is either encased in the concrete of the pilaster member or, if it is to be axiall~ movable, with respect to the pilaster member, it is placed in a ~ormwork tube encased in the concrete.
'.
In the region of the change in direction point, the ten-sion elements must be arranged in an orderly manner, whereby spacers 112 are provided in this region which have openings through which the tension elements 12 extend. For the instal-. 1 .
lation of the spacers 112, there are several possibilities,installation intermediate spacers are allowed to remain at the change in direction points in the tubular envelope or in the sheathing tube 16 in order to stop the tension elements 12 during the pushing-in operation and to be able to thread them into appropriate openings in the spacer, or to install the spacers in another manner for subsequently moving them into the predetermined position at the change of direction point by axial displacement along the tension member or together with :
¦ the tension member.
To provide a smooth transition of the change of direction forces in the region of the change in direction points during tensioning of the tension member~ 10, the region of the curved ~.
^"` ~L3~
sheathiny tube 110 can, before the tensioning, be injected with hardenable material 22, for instance, cement mortar. For this purpose, the sheathing tube is sealed at both of its ends. The sealing action can be effected by insert pieces 114, constructed similar to the anchoring pot 20, note Figure 5. The insert pieces 114 are placed into the sheathing tube from the ends and have a base provided with openings for pass-ing the tension elements through them. The hollow space formed by the insert pieces is to be filled with a hardenable material, such as cement mortar. At one end, an injection hose 115 proiects into the curved sheathing tube and a venting tube or opening is provided at the other end so that any open vo]ume remaining within the sheathing tube 110 and around the sheathing ducts 13 of the strands 12 is filled with the harden-able material, that is, cement mortar. After the material has ;I hardened, the tension elements remain axially movable within their sheathing ducts 13 and can be tensioned. The strands 12 wlth the sheathing ducts 13 can for additional protection also extend through separate guidance tubelets formed of plastics material along the length of the change in direction regionO
In a simiLar manner lt is also possible beforehand to inject the sheathing tube with previously installed spacers and guidance tubelets and to position it in the prefabricated i! state.
, Finally, it is possible to provide a smooth redirection of the tension elements 12 at the chan~e in direction point so , i I
' -42-` ~3~8~
that spacers 112 formed of a plastic material are arranged in a sealed manner next to one another with aligned openings~
The described placement of the spacers assumes segmental injection of the entire cavity within the tubular sheathing.
To be able to fill the entire cavity after tensioning of the tension member, it is also possible to design the spacers in such a way and from such a material that they can carry the change in direction forces developed during the tensioning step and thus transmit the forces to the structural member.
This can be achieved if the spacers are formed of metal, such `I
as cast ironO In addition to passageways for the tension elements, the spacers must also provide passages .for the in-jected hardenable material.
~; i ., .
The connection of the curved sheathing tube 110 with the ~' adjacent parts of the sheathing tube 16 can, while bridgingover the intermediate spacers, take place in the manner described in connection with Figure 5, by sleeves and hose Il connectors, and also by means of the bolt-connected flanges .l described in Figure 11.
~While speclflc embodiments of the inventlon have been .i shown and described in detail to lllustrate the application of the inventive principIes, it will be understood that the invention may be embodied otherwise without departing from li such principles.
lll ~ -43-
BACKGROUND OF THE INVENTION
The present invention is directed to a tension member protected against corrosion, mainly a tendon for prestressing concrete with post-tensioning. The tension member is formed of at least one tension element, such as a steel rod, wire or strand, located within a tubular envelope with anchoring de-vices arranged at the ends of the tension memberO The tension member extends between anchor regions at the anchoring devices, ,, with a free region extending between the anchor regions. In the free region, the tubular envelope is formed of a sheathing tube and is tlghtly secured to the anchoring devices in the anchor region. Open spaces are provided between the indivi-dual tension elements within the tubular envelope and at least in the region directly adjoining the anchoring devices the l open spaces are filled with a plastically deformable corrosion-protection mass. Further, the invention is directed to a method of installing the tension member in a concrete struc-tural member.
~.1 In structural design, particularly of bridge structures formed~of prestessed concrete, prestressing with pretensioning ¦ ~ and with post-tensioning is known. Prestxessing with ¦ ~pretensioning is performed mainly as prestressing with subsequent pretensioning where the tendons or tension members remain~free to move until the concrete sets and are subse-quently bonded to the structure by injecting grout. In pre-I
li ~3U~
stressing with post-tensioning, the tension members are gener-ally located outside of the concrete structurej though they are supported relative to the structure, they can be inspected at any time,and, if necessary, retensioned or replaced.
'.
Tension members used as tendons for prestressed concrete with post-tensioning, or as diagonal cables for stayed cable bridges or for the rehabilitation of structural members and other structural tasks, require permanent corrosion protection made up of two independent corrosion protected systems with each system being completely effective by itself. A known tendon of this type, (Dyckerhoff & Widmann Publication "DYWIDAG~-Report", No~ 11, 1982, page 7) is formed of a pre-stressed tendon surrounded by a polyethylene sheathing tube across the free region of the tendon. The annular space be-tween the tendon and the sheathing tube is closed of~ at the ends of the tendon by seals and the annular space can be injected with a hardenable material, such as cement mortar.
Such a hardening material forms the first corrosion protection system across the free reglon of the tendon, the second cor- ¦
rosion protection system is the sheathing tube itself. In the anchor reglons, the sheathing tube is joined with a connecting tube and the connecting tube is joined to the anchoring plate of the anchoring device. To maintain the tendon so that it can be stressed, prestressed or replaced, the corrosion resis-tance in the anchor region is provided by a plastically deformable corrosion-pr~tection mass, such as grease, filled under pressure into the annular space between the tendon and the connecting tube. Accordingly, in the anchor region, the first corrosion protection system is the corrosion protection mass and the second system is formed by the connecting tube joined to the anchoring plate.
With such an arrangement, doubtless there is the advan-tage that the use of a comparatively expensive corrosion protec-tion mass can be limited to the anchor region, while the less expensive cement mortar is utilized for the free region of the tendon which represents a considerably larger volume. There is the disadvanta~e, however, that the cement mortar must be injected prior to the installation of the tendon, since the annular space in the free region of the tendon is not acces-sible after lnstallation because an anchor tube is fixed to the anchoring plate. While this arrangement is acceptable in the case of individual tendons formed of a single tension rod, however, with bundled tendons r it is not acceptable, since the tendons could not be handIed due to the great weight involved.
; 1 Furthermore, segmented fabrlcation of structures, such as the fabrication of bridge structures ln the so-called time-¦ shifting or incremental launching method often necessitates the provision of an addltional tendon for a subsequen-t section to a tendon already anchored to the section, and the connec-tion of such tendons, so that the entire tendon can be ten-sioned from the opposite ends.
'I
~ ~ -4-For tendons with subsequent pretensioning so-called cou-pling points are known for joining the tendons. Thus, an anchoring and coupling device of one bundled tendon comprises one anchoring member which, in addition to conical bores for ~ prestressed anchoring of the incoming tension members by I means of wedges also has additional conical bores oriented in the opposite direction for anchoring the outgoing tension members (DE-PS 32 2~ 702)o Such bores are arranged uniformly across the surface of the anchoring member. In this anchoring member, cylindrical bores follow the conical bores for anchor-ing the outgoing tensioning members and such bores are filled I !
with a permanently plastic lubricating corrosion protection mass, whereby the tension elements are freely extended across these comparatively short axial dis~ances. By injecting the entire remaining tubular enclosure with hardenable material, such as cement grout, a certain spring action of the tendon is l utilized because of the short bond-free distance of the out-I going tension member, and the danger of crack formation in the coupling joint is reduced.
.
., 1 SUMMARY OF THE IN~ENTION
Therefore, it is the primary ob~ect of the present inven-tion to provide a tension member which can be retensioned or replaced, especially a bundled tension member or tendon, where not only different corrosion protection material can be uti- ¦
lized in -the anchor regions and in the free regions of the ~5~
I' ~3~ 5 tension member, rather such materials can be applied indepen-den-tly of each other and without mutual interaction to a struc-; ture. It may even be possible to supply the material afterthe installation of the tension member. In addition, it is ; possible to construct a tension member of two or more axially , extending sections coupled together in a friction locked manner.
',' In accordance with the present invention, each of the tension elements forming the tension member is enclosed in a sheathing duct formed of a plastics material, such as poly-I¦ ethylene and a plastically deformable corrosion protection mass fills the space between each tension element and the ;i . i enclosing sheathing duct. The hollow spaces located between I the individual ducts and the tubular envelope of the entire ! tension member is filled with a hardenable material, such as ! cement mortar, except in the regions directly adjoining the 1~ anchoring devices, into which the ducts of the tension ele-; ments penetrate. This region, adjoining the anchoring device, ~;
is filled with a plastically deformable corrosion protection mass.
Accordingly, the present invention provides a tension member or tendon, especially a bundled tendon, in which individual tension elements, preferably steel wire strands, are enclosed along with entire length, including the anchoring devices, by a plastically deformable corrosion protection mass, whereby the tension elements remain permanently axially !i ',~
' movable and retensionable. By utilizing tension elements, enclosed within polyethylene ducts, as so-called greased ; strands, there is provided a limitation of the space to be ~ filled with the plastically deformable corrosion-protection , ~
mass to the region immediately surrounding the individual tension elements and to the space directly adjoining the anchoring devices. ~he ducts for the tension elements provide a barrier between the corrosion protection mass enclosed in the ducts and surrounding the elements and the outer tubular envelope of the over-all tension member, so that the remaining open space within the tubular envelope can be filled with a hardenable material, such as low-cost cement mortar. Such a hardenable material not only affords a smooth transition at change in direction points during the expansion of the tensionin~ of the tension elements at the anchoring devices and at the change in direction points, but it also affords an additional protection if there is any failure of the grease Forrosion protection.
In accordance wlth the invention, not only is free axial J
mobility of the tension elements~forming the tension member maintained, there is also the advantage of installing such a tension member including its tubular envelope or enclosure with the furthex possibility of removing such a member if the tendon is only~being utilized in the construction of a bridger I but is unnecessary in the finished bridge structure. Moreover, Il such a tendon can be replaced in the structure by another tendon if it were to become damaged. In accordance with the invention, the tubular envelope in the anchoring region is formed of an anchoring tube coopera-ting with an abutment mem-ber so that an anchoring pot can be inserted within the tube leaving an annular space between them. The anchoring pot has a number of openings in its base corresponding to the number of tension elements and, at its end spaced from the base, it has a flange forming an annular space, and the anchoring pot is filled with a plastically deformable corrosion protection mass.
, The abutment member, against which an anchoring disc penetrated by the tension elements comes to rest, includes in an advantageous manner at least one injection and/or venting aperture for the hardenable material being charged into the ! annular space.
.
., The anchoring tube inserted into a central opening of the abutment member preferably has a flange abuting against an annular shoulder formed in the opening. An elastic material sealing ring is preferably arranged between the flange of the anchoring tube and the annular shoulder.
~; fl The anchoring tube is provided with spaced protuberances arranged around its circumference at its end against which the ,1 anchoring pot rests. The anchoring disc can be provided with a tubular extension at its side facing the abutment member ,1 !I with the extension passing into the anchoring pot in a tele- ¦
I scoping manner.
'', .
The advantage of the invention is that in the anchor region and particularly in the anchoring pot, there is a cor-rosion protection mass with the anchoring pot being placed in a simple assembly procedure on the tension elements previousl~
inserted and then slipped into the anchoring tube. The an-choring pot, as compared to the anchoring tube, is shaped so that an annular space remains in the region of the abutment memberwhere injection and/or venting lines are provided and which continues around its circumference with an annular space.
The annular space affords a connection to the hollow space in the free region of the tension member outside the anchoring pot, so that it can be injected with a hardenable material, pre~erably cement mortar. Preferably, the anchoring pot prevents the material from penetrating into the anchor region and fixes the anchoring means, such as anchoring wedges. ' ~.
The ducts enclosing the individual tension elements ex-tend into the anchoring pot filled with corrosion protection mass and thus assure complete corroslon protection.
1 ~Additlonal advantages follow from the loose connection fl between the anchoring tube and the abutment member, in that the anchoring tube lS provided with a flange at its end ex-posed to the atmosphere and can be pushed through the central l opening of the abutment member, where it comes into contact with an annular shoulderO This simplifies the assembly, and, in addition, affords compelsation fcr angular differences _9_ 1, ~
~3~
between the anchoring tube contacting the tension elements and the abutment member, particularly if an elastic material seal-ing ring is positioned between the flange of the anchoring tube and the annular shoulder. The tubular extension on the anchoring disc facilitates the installation by engaging within the anchoring pot and assuring a self-centering action.
The anchoring tube widens toward the anchoring device in a trumpet-like manner. An intermediate layer of an elastically and/or plastically deformable material, such as a plastics material, can be located between at least the outer tension ` elements and the inner surface of the anchoring tube for af-fording a smooth transition of change in direction forces.
The intermediate layer can be in the form of a ring in contact with the inside surface of the anchoring tube. In place of I the intermediate layer, the outer tension elements can be I conducted through a plastics material sheathing tubeO
~ I
If comparatively short tension elements are used, the length of the anchoring pot is selected so that the ends of the plastics material sheathing ducts do not become displaced from the anchoring pot if changes in length of the plastics material sheathing ducts is caused by temperature differences.
If comparatively long tension elements are employed, the plastics material sheathing ducts can be prevented from sliding out of the anchoring pot by providin~ an enlargement around their circumferences.
!l ,, The anchoring tube is appropriately connected with the tubular envelope in the free region of the tension member in a tension-proof manner.
An expansion joint can be provided along the tension member to compensa-te for changes in length due to temperature differences. At the expansion joint, the tubular envelope is b~tt-jointed and the joint is tightly overlapped by an outer sleeve connected with a portion of the tubular envelope.
The hardenable material which fills the space outwardly of the individual sheathing ducts on the tension elements and the tubular envelope can be provided with reinforcement to avoid cracks.
To construct such a tension member or tendon in series from two or more axially extending sections, at least one of the anchoring devices can be constructed as a coupling member with the preferably circular anchoring disc abutted against the abutment member having bores for anchoring the incoming tension elements and additional bores for anchoring the out-going tension elements. In addition, a sealing disc closes off the hollow spaces formed about the tubular ducts and is provided with opening for at least the outgoing tension ele-ments and is arranged in the region of the outgoing tension elements spaced from the anchoring disc~ The hollow space located between the sealin~ disc and the anchoring device is .1 ~I
., I, --1 1--filled with a plastically deformable corrosion-protection ; mass, for instance greaseO
Accordingly, it is possible to use such a tension member as a tendon for prestressed concrete with post-tensioning in structures to be constructed in sections, such as construction ~` by incremental launching method type bridges.
.
The tubular envelope about the outgoing tension elements, in the region adjacent to the anchoring device is in the form of a casing, for instance, formed of metal, which can be connected in a sealed, as well as pressure and tension-proof '~
manner. Further, it is detachable from the anchoring device and the tubular envelope in the free region of the tension member.
After the expansion of the outgoing tension elements towards the anchoring disc, the casing can be formed of a number of sections of different diameters and, further, can be made up of parts separate from one another in the sections of , different diameters. Such parts are preferably displaceable with respect to one another in a telescoping manner and are detachably connected to one anotherO
Expediently, the sealing disc is located at a transition point between two sec-tions of the casing with different diam-eters and the sealing disc can be detachably connected to the casing.
It is also possible to arrange the sealing disc as a spacer for the tension elements and for carrying change in direction forces oriented radially inwardly and caused by the increased spacing of the tension elementsO The sealing disc is formed of two plates pressed against one another with seal-ing rings interposed between them and surrounding the tension elements where they pass through the plates.
;'` ', A redirecting member laterally encircling the bundle of ~! tension elements in an annular manner is arranged for carrying the change in direction forces oriented radially outwardly at the beginning of the spreading or further spacing apart of the tension elements. This redirection member is located inside the tubular enclosure or envelope and is detachably connected with it.
l l l ,!
~ l~The tubular envelope,enclosing the tension elements in il i the free region of the tension member,extends into the redirec-tion member forming an intermediate layer between the tension ~ elements and -the redirection member. -I To arrange the outgoing tension elements in an orderly i manner, an expansion ring, preferably formed of plastics mate-rial, is located in the region of the redirection member. At its outer circumference, the ring has receptacles for fixing ¦¦ the tension elements individually or in groups. These recept-~l acles can be formed as radiaI websO Further, the expansion :
!
., li -13-, I
I
~3B~
ring can be constructed as a sealing disc. Where a tendon is post-tensioned, and is located outside of the concrete cross-section of a structural member, it is impossible, as a rule, to adapt the axis of the tendon or tension member to the course of the bending moments in a continuously curved manner.
Generally, it is necessary to guide the tension member approximately at a multi-sided train.
"
As a result, change in direction points are formed where forces oriented toward the inside of the curve have to be carried. In the region of these change in direction points, the tubular envelope is conducted, in accordance with the invention, along a circular arc, to aEford a smooth transition of the change in direction forces. By axially mobile guidance of the tubular envelope at these change in direction points, 1¦ it is possible to make the tension member removable, if it is necessary to replace it. Spacers are located in these change in direction regions with the spacer forminy openings to which .
the tension elements pass~ ~
I
It is important in the method of installing such a ten-sion member that the hollow space between the encased tension elements and the tubular envelope is filled with a hardenable material at least in the region of the change in direction before the tension member is stressed, so that the change in direction forces can be carried with a smooth transition. The ¦
axial mobility of the tensLon element with respect to the structure is, as a rule, also maintained in the region of the '~ "
! -14-change in direction points. If differential forces are to be applied at the change in direction points, then a bonding between the tension elements and the structure must be pro-duced. Such a bonding can be effected in a known manner.
, , The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described pre~erred embodiments of the invention.
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DESCRIPTION OF THE DRAWINGS
In the drawings:
Figure l is an axially extending view, partly in section, of a bridge support structure using tension members, in accordance with the present invention, as tendons with j post-tensioning, with the view taken along line I-I in Figure Figure 2 is a transverse cross-sectional view through the bridge structure taken along the line II-II in Figure l;
-15~
Figure 3 is an enlarged view of an anchoring region in the bridge support structure;
Figure 4 is an axially extending sectional view of , an anchoring and coupling region of the tension member embodying the present invention and corresponding to Figure 3;
, Figure 5 is a view, partly in axial section, and partly in side view, on an enlarged scale, as compared to : ~I Figures 3 and 4, illustrating the anchorlng region of a l¦ tension member embodying the present invention;
: Figure 6 is a transverse sectional view, taken along the line VI-VI in Figure 5;
Figure 7 is an enlarged partial view of a portion of 'I
the anchoring region in Pigure 5, and displayed on an enlarged scale;
.
,, , i i! !
Pigure 8 is a exploded view of an anchoring region for the tensIon~member of the present invention, and displayed Y in section;
j Figure 9 is a partial axially extending section llustrating another embodiment of the anchoring region of a ll tension member, in~accordance~with the present invention;
: !l ~
~: i'1 .
~1 Figure 10 is a vlew in axial section of the anchor-ing region of a tension member illustrating another embodiment of the present invention;
,, Figure 11 is a a view similar to Figure 10 of still another embodiment of the anchoring region of a tension member in accordance with the present invention;
, Figure 12 is a partial axial view through an anchor-I ,l ing pot for fixing the sheathing duct of a tension element;
1, .
Figure 13 is a transverse sectional view taken along .
the line XIII-XIII in Figure 12; - ' ., I
Figure 14 is a schematic showing o an expansion joint in the tubular envelope for the tension member;
Figure 15 displays a partial axial section of an anchoring and coupling region for a tension member embodying the present invention and set forth on an enlarged scale;
: ~ :5 : : ~
Figure 16 is a partial axially extending section ~5 ~ through an anchoring device with an anchoring disc;
Figure 17 is a partlal axially extending section ',i thr~ough a sealing dlsc in the region of the outgoing tension 1~ elements;
', ~, ~, 313U~
Figures 18a and 18b are, partial axially extending sections, at the end of the tension element widening region of the outgoing tension elements;
Figure 19 is a partial transverse sectional view through the outgoing tension elements shown in Figures 18a and 18b;
, Figure 20 is a partial axially extending section through an anchoring device embodying the present invention and including another embodiment of an anchoring disc;
;l .
'. Figure 21 is an enlarged sectional view of a portion "
Il of the anchoring device as shown in Figure 20; and ,1 , j Figure 22 is an axially extending view of a change ' in direction point of a tenslon memher embodying the present :~ invention shown partially in axially extending section and !
~' partially in side view.
1~ ', !
1, , -18-., '1 130~;S
DETAILED DESCRIPTION OF PREFERRED
EMBODIMENTS OF THE PRESENT INVENTION
_ _ . . . . _ .
In Figures 1 and 2, a bridge deck or roadway 1 is illustrated with a closed trapezordally-shaped cross-section and the roadway is produced by the known incremental launching method. The bridge deck is formed of two elongated inclined girder webs 2, joined at their lower ends by a horizontal base plate 3, and at their upper end by a deck plate 4, extending between the upper ends of the webs and continued laterally outwaardly from the webs by cantilevered sections 5.
, .
The bridge deck 1 is prestressed by tension members or tendons with post-tensioning. In Figure 1, which is not to scale, an axially extending section is provided and illustrates schematically one axially extending section of the bridge deck ; I 1, between a fixed support 6, and a movable support 7, with the tension member 10 provided with an axis 11. In accordance with the characteristic of a continuous girder, the tension axls 11 shown in the cross-sect1on of Figure ~, is located in i the upper part of the cross-section and in another part of the axial section in its lower region, not shown. Within the deck 1: ~ 1 ~ cross-section, the tendons are located passing through the l1 side pilaster members 8, where they are anchored and possibly o~erlap, as well as in the region of the pilaster members 9, in which the tendons undergo~a change in direction, that is, t hey represent change in direction points. The pilaster li members 8, 9 extend inwardly from the inside surfaces of the ~' legs 2.
'i . I
130~lS~
An anchor region of the tension member 10 is displayed on a larger scale in Figure 3, shown partially in axial section and partially in side viewD The tension member 10 is made up of a bundle of tension elements, for instance strands 12 of steel wire, each enclosed within a casing or sheathing duct 13 for corrosion protection. The hollow space within the sheathing ducts 13, around the strands, is filled with a plastically deformable corrosion protection mass, such as grease. The strands or tension elements 12, located within the sheathing ducts 13 are enclosed within an axially ex-tending tubular envelope 1~. The tendon 10 abuts against a piIaster member 8 by means of an anchorage device 15.
. . .
Tubular envelope 14 in the normal or free region A of the tension member 12 is a plastics material sheathing tube, for instance, polyethylene, connected adjacent to the anchorage device 15 to a cast iron anchoring tube 17, with the tube widenlng in a tru~pet-like manner toward the anchorage device 15~ In the adjacent region B, forming a part of the anchor region, the spacing of the tension elements is increased towards an anchoring disc 18 for effecting the anchorage of the elements, that is, the over-all transverse cross-section of the tension member 10, formed by the elements 12, increases from the region A toward the anchorage. The anchoring disc 18 "
abuts against an abutment plate l9 bearin~ a~ainst one side o~ i the pilaster member 8, this region is designated as region C
forming part of the anchoring region.
1 !
.
~3~
The tension elements within the region B pass through the base plate of an anchoring pot 20, located within the anchor-ing tube 17 in a sealed manner. The anchoring pot is filled with a plastically deformable corrosion-protection material 21, such as grease. Note, in Figures 3 and 4, the regions I, II located above the anchorage. The region I extends from the anchoring disc to the base plate of the anchoring pot. In the region I, the tension elements 12 are axially movable in the corrosion protection mass 21 and in the outer region II, extending away from the anchoring pot are axially movable within the sheathing ducts 13. Externally of the anchoring pot 20 and in the region II, the hollow space or volume between the sheathing ducts 13 and the sheathing tube are envelope 16, is pressure injected with a hardenable material '~ 22, for instance, cement mortar.
i~
The anchor region of the bundled tension member 10, shown only generally in Figure 3, is displayed on a larger scale in Figures 5 to 7. Tension elements 12 are anchored in conical bores 24 within the anchoring disc by means of multipart tapered collars or wedges 23. Anchorlng disc 18 abuts via shims 25 against an abutment plate 19, and the abutment plate I ! bears against the outside surface of the pilaster member 8, as !
shown in Figure 5, or it can also be embedded in the pilaster ,I member. Abutment plate 19 includes an axially extending ll tubular section 26 extends into a tubular recess 127 with a !' slightly larger diameter than the tubular section with a ~ -21 'i 1 .~ ~3(~355 recess 28 extending through the pilaster member and forming an opening through which the tension member 10 passes. Sheathing tube 16 is connected to the anchoring tube 17 adjacent to the anchorage, leaving an intermediate space. In the structure illustrated in Figure 5, the connection between the tubes 16 I and 17 is in the form of a butt joint made up of a sleeve 29, for instance, formed of plastics material, encircling the ends of the sheathing tube 16 and the anchoring tube 17, adjacent to one another, with the sleeve 29 fastened in place by clamps, such as hose connectors 30. ~.
''' Anchoring tube 17 is formed of cast iron and thus is able to carry the change in direction forces generated by the widen--ing of the spaces between the individual tension elements and passes through a opening in the abutment plate 19. In the detail in Figure 7, anchoring tube 17 includes an outwardly bent flange 32 at its end, adjacent the anchorage, and the flange rests agai.nst an annular shoulder 34 in the abutment plate with the interposition of a sealing ring~33 made of an elastic material, for instance, rubber, with the annular shoulder narrowin~ the central opening 31 at the side of the abutment plate facing toward the anchoring pot 20. At its end, within the opening 31 in the abutment plate 19, the anchoring tube 17 is provided with protuberances 35 uniformly spaced in the circumferential direction with the protuberances extendlng radially outwardly, and also in the axial direction beyond the flange 32 toward the anchoring disc 18.
1, ~ -22-~3()~8SS
As displayed best in Fiyure 8, an anchoring pot 20 is inserted into the anchoring tube 17 and has an outside dia-meter at this location somewhat smaller than the inside di-ameter of the anchoring tube 17. Anchoring po-t 20 is centered in the anchoring tube 17 by the radially inner portion of the protruberances 35, and is maintained from the inner surface of the anchorin~ tube so that an ann~lar gap or space 36, note Fi$ure 5, is located between them. The anchoring pot 20 has a ~ottom or base 37 at its end more~ remote from the anchoring disc 1~ and the base has a number of openings 38 so tha-t the :i! !
teDsion e1ements 12, along with ~heir sheat~ing ducts 13 can pass throug~ the openings. A tubular exte~sion 18a on the anchoringi disc 18, extends into the ancho~.ing pot in the re~ion of the abutment plate 1~ and provicles a cen~ering a~tion ~or the anchoring disc~
Anch~ring pot 20 has a flange 39 a~ its end, closer to the anchoring disc 18, note Figure 7, and the flange contacts ' the protuberances 35 on the flange 32 o the anchoring tube, that is the ends of the pro~uberances.facing toward the anchor~
in~ dlsc 18. As a result~:an annular space 40 is provided in the region of the abutment plate 19, limited inwardly by the an~h~.~ri~ ~ot 20, and radially outwardly by the surface of the ~i!' o~in~ 31 in the abutment p~ate 19, and on the opposite sides . are th2 ~lla~ges 32 and 39 of the anchorin~ tube 17 and the : 1` ah~horing p~t 20. Several in¦ection aper~ures 41 extend into ~l the ~nnul~r -space 40 and pass through the ~butment plate 19, .
`- ` 13~
note Figures 5 and 7. Annular space 40 is in flow communi-cation with the inner hollow space within the sheathing tube 16, via the annular gap or space 36, between the anchoring pot 20 and the anchoring tube 17, so that the hollow space can be ; injected with hardenable material, for instance, cement mortar through the injection apertures 41, and a corresponding ~ venting opening provided at the opposite anchorage.
I ~ From Figure 5, it can be noted how the hollow space with-in the anchoring pot 20 is filled with a plastic corrosion-protection mass, such as grease, which assures the corrosion-protection in the region of the anchorage and permits subse-quent detachment of the wedges 23 for retensioning or loosen-ing the tension on the tension member 10 in order to replace it. Shims 25 also serve in reducing the tension. The cor-,1 ~
rosion-protection mass 21 has direct connection in the region ~ of the anchoring pot 20 to the corresponding corrosion-I protection mass within the sheathing ducts 13 enclosing thetension elements 12. The hollow space remaining between the sheathing ducts 13 and the inner surface of the over-all sheathing tube 16 can be injected through the annular space 40 ¦ and the annular gaps 46 with a hardenable corrosion-protection material 22, for instance cement mortar, which passes over the a~choring pot 20, filled with grease.
!l I
i The condition in the region where the space between the tension elements is increased in the anchoring tube 17 is ~ .
~``` 1;~0~)~5~
explained in detail with the aid of Figures g, 10 and 11. At this location, it is necessary to redirect at least the ten-sion elements located in the radially outer part of the bundle in a smooth transition and to guide them so that their metallic surface does not slide on the inner metallic surface of the anchoring tube during the tensioning step which interaction could cause frictional corrosion. Accordingly, as shown in Figure 9, a ring 44 of a plastics material, for instance, polyethylene, is located in the portion of the anchoring tube where the increase in the spacing of the tension elements is commenced, note Figure 9. Ring 44 is inserted into a widened portion in the wall of the anchoring tube forming a seat in the inside surface of the tube so that the ring projects in-wardly from the inside surface and thus assures a smooth guid-ance of the tension elements in this region and a smooth transi-tion of the redirection forces.
' A similar efect can be achieved, as shown in Figure 10, if the radially outer tension elements in the bundle are pro-vided with sleeves 47 of plastics material. Further, Figure . . , ~ 10 shows a connection between the anchoring tube 17 and the li ~ .
sheathing tube 16' in the free region of the tension member ¦ 10, that is, between and spaced from the anchoragesO It is expedient in certain cases to form a solid connection between the~two tubes forming the tubular envelope for the tension member. The connection can be achieved by providing the , .
anchoring tube 17' and the sheathing tube 16' with flanges .1 1 18, 49, respectively, with the flanges connected in a tension-proof manner by screws 500 Ano~her embodiment for ~he connection of the sheathing tube to the anchoring tube in the free region of the tension member is i.llustrated in Figure 11. Similar to the embodiment in Figure 10, the anchoring tube 17'l has a outwardly directed flange 48 at one end, the sheathing tube 16 " is welded at its adjacent end by a welding seam 51, with an intermediate piece 52 of approximately T-shaped cross-section of the same mate-rial as the sheathing tube 16 " ~ At the opposite end of the tubular inner portion of the intermediate piece 52, an axially extending tubular section 54 is secured by a welding seam 53 at the beginning of the trumpet-like expansion of the anchor-ing tube 17 " with its smooth lining affording support for the radially outer individual tension elements 12. In this embodi-ment, the sheathing tube 16'' with the i.ntermediate piece 52 is lengthened for extending into the anchoring tube 17'' af-fording a continuous support for t~e individual tension ele-ments 12 in this critical region. The radially projecting part of the intermediate piece bears against the flange 48 on the adjacent end of the anchoring tube 17 " , and is secured to the flange by a ring 54' and bolts 50.
In view of this connection, to avoid excessive tension forces in the sheathing tube 16, caused by temperature differ-ences, an expansion joint 55 can be provided at any point along the tension member 10, note Figure 14. Since the external corrosion-protection system, that is, the tubular ., ~
; -26-, I
:IL30~S~
envelope for sheathing tube 16, is interrupted at the expan-sion joint, a leak-proof connection is provided. This feature is indicated in the illustrated embodiment by an inner tube 56 and an external tube 57, which is fastened at one end by a welding seam 58 and is sealed at its other end against the outside surface of the tubular envelope by sealing rings 59.
When using the tension elements 12 with their sheathing ducts 13, according to the invention, attention must be paid to the fact, in changes of length in the sheathing ducts 13, due to temperature differences to which the tension member 10 is exposed, since i~ is not concreted into the structure, that the she~thing ducts do not slide out of the anchoring pot 20 filled with the corrosion-protection mass 22. In the case of short tendons where only minor changes in length occur, the axial length of the anchoring pot can be such that changes in length of the sheathing ducts 13 occurs within the limits of the actual length of the pot. With longer tension membersr it . .
is necessary to prevent extensive changes in the length of the i sheathing ducts 13. This can be accomplished in a simple manner by fastening the ends of the sheathing ducts 13 within the anchoring pot 20 so that they cannot slide through the '.l opening 38 in the base 37 of the anchoring pot 20. This can ~I be achieved in various ways, some of whlch are illustrated in Figure 10, as well as in Figures 12 and 13. A clampin~ sleeve 60, formed of a plastics material, is placed at the end of the ¦ sheathiny duct 13 on a tension element 12, and the clamping .
''I I
'` ;
~3C~3;,5 sleeve is provided with a axially extending slot 61 and with ribs in its inside surface, that is, with an internal thread affording a friction and/or positive locking connection with the sheathing duct 13. A similar effect can be attained with ~, I
hose clamps, tapered sleeves, or the like.
l, The assembly of the anchoring device described above is as follows: Initially, an abutment plate l9 is enclosed in concrete within a structural member, for instance, the pilaster member 8, shown in Figure 3, in such a way that its axially extending tension tube 26, together with the tubular recess 27, forms an opening 28 for the tension member lO. After placement of the sheathing tube 16, which may be made up of several axially extending sections, if, as shown in Figure l, change in direction points are present, the anchoring tube 17, with the sealing ring 33, is provided at both ends and is connected to the sheathing tube 16. For axial mobility during assembly, the final connection occurs only at the anchoring end.
Next, tension elements 12, provided at both ends with ~ , numbered tags for identification, are slid from a coil into the sheathing tube 16 by a sliding-in device, not shown. When aIl of the tension elements have been inserted, an anchoring pot 20 is pushed on each of the ends of the tension member lO.
Care must be taken that the numbered tension elements 12 reach corresponding openings 38 in the base 37 of the anchoring pots 20 at the opposite ends of the tension elements. The openings 38 are sealed to a degree by the sheathing ducts 13. Next, ~ ~3~3~55 the sheathing ducts 13 on the tension elements 12, in the anchor region, can be removed and the anchoring pot filled with the pasty corrosion-protection mass 21, if it has not already been filled prior to this timeO
A spacer 42 is then slid onto the tension elements 12, whereby the spacer prevents direct contact of the tension elements 12 with the anchoring disc 18, note Figure 5, and maintains the parallel guidance of the tension elements, so that there is no reduction in the vibration strength. Subse-i, quently, the anchoring disc 18 with its tubular extension 18a ~!
and the shims 25 are slipped on the ends of the tension ele-ments and the corrosion-protection mass 21 is further compac-ted. Accordingly, the tubular extension 18a affords a self-centering of the anchoring disc 18, while being slipped into the anchoring tube 17, note Figure 8. Finally, the annular ` wedges 23 are inserted into the conical bores 24 in the anchoring disc 18.
., !
Subsequently, it is helpful to stretch the tension ele-ments 12 individually with a light duty hydraulic press, prior to tens1oning all of the tension elements -together with a ¦ bundle tensioning press or jack. If necessary, the portions of the tension elements extending beyond the anchorage are cut off and a corrosion-protection mass is injected with the help of a grease gun through hores in the anchoring disc 180 For positive corrosion protection of the anchorage, a protective ~1 1 - - \
~3~855 .
covering is placed over the ends of the tension elements pro-jecting outwardly from the anchorage and the cover is filled with a corrosion-protection mass 21, note Figure 5. Where-upon, the posi-tive connection of the casin~ with the anchorage .; and the connection of the sheathing tube 16 with the anchoring tube 17 can be effected and, finally, the hollow volume re-maining within the free reyion of the sheathing tube 16 can be pressure-injected in the described manner through the injec- ;
` tion openings 41 with a hardenable material, such as cement mortar.
. I I
To prevent cracks in the hardened cement mortar as a result of length changes of the tensi.on member 10 due to temperature differences, since the cement mortar does not bond with the tension elements 12 or the sheathing tube 16, the cement mortar should be reinforced. Reinforcement can be j provided by using grout in which glass fibers or the like have been added or into which one or more steel wires as reinforce-ment of the mortar along with the tension elements 12 within the sheathing -tube 16.
il , In Figure 4 and in Figures lS to 21, an anchorage or anchor point acting also as a coupling point is shown. In Figure 4, such a combination is shown partly in axial section I and partly in side view. Basically, the tension member 10 is : designed in the same manner as shown in Figures 3 and 5. In this case, however, the tension member abuts only by means of I
~1 ~, , -30-~ ` 13(~
the anchoring device 15', used only as an intermediate anchor-age, against the pilaster member 8, forming part of a construc-tion member, and is continued in the direction away from the pilaster member from the anchoring device 15' up to the next anchoring device designed as an end anchorage in accordance with Figures 3 and 5. The portion of the over-all tension :1 .
member 10 to the right of the anchoring device 15' in Figure 4 is designated as the "incoming" portion 107, while the portion to the left of the anchoring device 15' in the Figure is desi~-nated as the "outgoing" portion 10''.
The tubular envelope in the combined anchoring and cou-pling region C and in the adjacent region D of the outgoing portion 10'' of the tension member 10 is formed by a casing 70 designed differently as a function of the lateral spreading of the tension elements 12''. Primarily, the casing 70 is formed of metal, however, it can be made of plastics material, such as polyethylene. In Figure 4, the casing 70 consists of two consecutive axially extending sections with stepped diameters fl affording a transition to the normal or free region E corre-sponding to the normal or free region A, where it is connected : 1,l to a sheathing tube 16 made of plastics material, for instance, polyethylene. The casing serves not only for mechanical and corrosion protection of the coupling point, but also for secur- ' ing a redirection member 71. If it is formed as a metal tube, it can also be used for the reduction of the bending mom~nts.
Tension elements 12, enclosed by sheathing ducts 13, l~ iormed of polyethylene in the axially extending normal regions il i I
13~ tii-3 A and E, as well as in the regions B and C, where the spacing of the elements is varied, and or guided within the anchoring tube 17 through the base 37 of the anchor pot 20 in a sealed manner and on the opposite side of the anchoring de~ice are guided in a sealed manner through a sealing washer 72. The base 37 and the sealing washer 72 form the axial bounds of the ~, .
region I, note Figure ~, of the tension member 10, in which the hollow space within the tubular envelope is ~illed with a plastically deformable corrosion-protection mass 21, for in-stance, grease, and in the remaining regions II on the op-posite sides of the region I, of the tension member 10, the exterior of the anchoring pot 20, is pressure injected with hardenable material, such as cement mortar 22. The tension elements 12 are guided for axial mobillty over the full length of the tension member 10 and are coupled in an overlapping manner in the region I adjacent the anchoring device 15 and filled with a corrosion-protection mass so that the tendon ~j member 10 made up of several axially-extending portions 10', , 10l' can be tensioned from the ends.
i ¦ The outgoing portion lO ":of the tendon is shown at a larger scale in partial axial cross-section in Figure 15 ~ith ¦! the essential parts illustrated in detail in Figure 16, 17 and 18.
l ll As can be determined from Figure 16, the incoming tension ¦
elements 12', note Figure 4, are kept in order in the region f' -32- ~
- ~ ~L3~
of -the abutment member 19 by a spacer 42 and pass through bores 73 in the anchoring disc 18' and are anchored by wedges 23 extending into the frusto-conical ends of the bores. The ends 74 of the tension élements 12' extend for a length beyond the anchoring disc 18' corresponding to the strain, so that it is possible to remove the tension from the entire tension memher or tendon. The anchoring disc 18' abuts against shim 75 and presses an intermediate ring 76 against the abutment plate or member 19.~ Anchoring disc 18' is centered within a central opening in the abutment member 19 by an extension tube 18a'. While the incoming tension elements 12' are anchored in the central region of the anchoring disc 18', the outgoing tension elements 12'' are anchored in the radially outer re~ion of the anchoring disc outwardly from the incoming tension elements 12'. Accordingly, the tension elements can be placed more easily in the required order. Moreover, the outgoing tension elements 12'l are accessible from the outside in the bores 78 so that the wedges 23 can be inserted in place.
To return the tension elements 12''j shown in parallel, from the position in the anchoring disc 187 to the spacing in the normal region E, a double change in direction is required, note Figure 15. The first change in direction of the tension element guided in a parallel member in the anchoring disc towards the inside, takes place in the region of the sealing washer 72 which is arranged so that it can carry the change in d.irection forces oriented inwardly. The second change in ~o~s~
direction of the tension elements 12'' takes place in the region of the redirection member 71 which must be able to carry the outwardly directed change in direction forces as annular tension forces. This, which is possible, the tension elements 12'' extending obliquely outward in the direction of their increased spacing, are anchored in appropriately oriented bores in the anchor ring disc 187, then it is not necessary to provide a change in direction in the region of the sealing washer 72~
Casing 70 forms the tubular enclosure 14 of the tension member 10 in the region C of the coupling and in the region D
where the spacing of the tension elements changes from the enlarged cross-section to the normal cross-section. Casing 70 is made up of two axially extending parts with different di-ameters 70a and 70b, note Figures 16 - 18. The larger diameter section 70a, has an outwardly bent flange 79 fastened by means of bolts 80 to the abutment member 19~ note Figure 16. At its opposite end, the section 70a has an inwardly bent flange 81 connected by means of bolts 83 with the adjacent smaller di-ameter section 70b, overlapping the flange 82, extending out-wardly from the adjacent section 70b. Section 70b, note Figure 18a, has an inwardly extending flange 84 to which a connection is made by bolts 85 between the sheathing tube 16 n the free region of the tension member 10 and the redirec-tion or change in directlon member 710 The two consecutive axlally extending sections 70a, 70b o:f the casing 70, are longitudinally displaceable in a telescopic manner relative to one another and to the adjacent sheathing tube 16, . 34-_~ ~3Q(~SS
as is appropriate during installation and disassembly or dur-ing removal of tension on the individual tension elements of the tension member 10.
, ~ The sealing washer 72 is formed of two plates 72a, 72b, Z note Figure 17, provided with registered bores for the passage of the tension elements 12. Outer plate 72b, more remote from the anchoring disc 18', is somewhat thicker in the embodiment 1l as shown so as to carry the change in direction forces. At the inner side of the washer 72, the bores are provided with stepped diameters, and sealing rings 87 are inserted into the increased diameter parts encircling one-bare tension element 12' or a strand with a sheathing duct 13, whereby the sealing ' rings rest in a leak-proof manner against the tension element I or are deformed so as to form a seal by pressing on the inner plate 72a by one or more bolts 88.
. . .
The redirection member 71 effecting the change in direc-tion of the tension elements 12 " in the outward direction consists in the embodiment of Figure 18a of a tubular section and while forming a contact surface for the tension elements 12' widens in a trumpet-like manner with a defined unwinding radius and has at its outer end an outwardly directed flange 90 drilled in the same manner as the flange 84 for receiving the bolts 85. In the embodiment of Figure 18b, the redirec-I tlon member 71' is formed of a solid annularly-shaped molded member 91 of greater thickness than the redirection member 71.
I
13~ r;~
The redirection member 71' has an appropriately curved radi-ally inner surface 92, and has threaded bores in its end sur-face facing the flange 84 for receiving attachment bolts 93.
To fasten the tension elements 12' in position until they are tensioned, an expansion ring 94 made of a plastics material is inserted inwardly of the redirection member 71 or 71'.
'.
Expansion ring 94 is shown in partial transverse section in Figure 19 and serves at the same time for arranging the tension elements 12'' in an a.nnularly-shaped order. Ac-cordingly, a number of receptacles or open spaces 95 are provided around the outer circumference of the expansion ring 94 with the individual receptacles spaced apart by radially I projecting webs 96. I
;, i In the installation or assembly of a tension member 10 with increased length due to the coupling point, the incoming , tension elements 12' are anchored after tensioning in the anchoring disc 18' as previously described. The anchoring i disc 18' abuts against the abutment member 19 through shims 75 ¦ and the intermediate ring 76 used for diameter equalization.
~ j! :Shims 75 are divided into two or more parts so that they can : ll be~removed later if tension is to be removed from the tension member. Intermediate ring 76 can be fastened by bolting it to i the abutment member 19.
,1 'I The two axially extending sections 7Oa, 7Ob of the casing 70 are fabricated separately and initially are slid over the Il sheathing tube 16 which has been readied for installation, prior to weldlng the flange g7 and part 98 continuing the sheathing tube at its end by means of a butt weld.
.' The redirection member 71 is then slipped onto the part 98, note Figures 18a, 18b. Next, the outgoing tension ele-ments 12' are placed into the sheathing tube 16 in the direc-tion of the anchoring device 15 and the sheathing ducts 13 are ~. ~
stripped from the ends of the tension element for approxi-mating the thickness of the anchoring disc 18'. The tubular part 98 continuing the sheathing tube 16, serves as an inter-mediate layer during the tensioning of the tension elements 12', to prevent metal-to-metal contact between the tension element and the redirec1-ion number 71. The tubular section 98 is deformed to conform with the change in direction of the "
' tension elements 12''.
.
Thereupon, the sealing washer 72 is installed. In this operation, the outer plate 72b is slid on and the sealing rings 87 are threaded on~ note F1gure 17. Next, the inner ,¦ plate 72a is posit~ioned and both plates are aligned relative to one another and are connected to one another by the bolts 88.~ As a result, the sealing rings are compressed and the ~, .
sealing force is activated. In the next operation, the Z
sections 70a, 70b of the casing 70 are displaced in a tele-scoping manner toward the anchoring device 15' and are bolted to the abutment member 19 and to the sealing washer 7~, as i 1 i1 :
' ~ 1i 3~
well as with the redirection member 71. At the same time, the sheathing tube 16 is fastened to the anchoring device 15' by positioning the flange 97 between the flanges on the portion 70b and the redi.rection member 71.
Before or only after tensioning of the tension elements 12', the corrosion-protection mass 21 is pressure injected into the region of the coupling point, and hardenable material 22, such as cement paste, is pressure injected into the .
remaining regions. Accordingly, injection tubes 99 are provided in the casing 70 and injection openings 41 in the abutment member 19, note Figure 16. The projecting ends 74 o the incoming tension elements 12' are protected by poIyethylene tubes inserted on them, note Figure 16.
~ I
"
If tension is to be released from the tension number 10, then the procedure above is reversed, starting with the out-, going tension elements 12 " and following with the incoming.
I tension elements 12' being relieved of tension. If only a partial release of tension is to be effected in the individual sections 10' or 10'' of the tension member 10, then only that section 70a of the casing 70 is displaced until the anchoring disc 18' is accessible, then the section 10 " of the tension member 10 is tensioned to the extent that the intermediate rlng 76 lifts off the abutment member 19 and the shim 75 can be removed. After renewed relaxation of the anchoring disc 18' upon the intermediate ring 76, the elongation is reduced. I
~l I
~ ' ~- -38-lil 3()~5~
by the thickness of the shims and with this also the tension force. A possible displacement of the end of the sheathing tube 16 in carrying out this procedure can be prevented, for instance by providing support against the abutment member.
~' .
i :
Another embodiment of the anchoring disc is displayed in Figures 20 and 21 which affords the possibility for placement of the anchoring disc against the abutment member 19 without the use of an intermediate ring 76.
. ~
The bores 73 for anchoring the tension elements 12' in the anchoring disc 18 " by means of the wedges 23 are arranged in the same manner as in the anchoring disc 18' as previously described. The anchoring disc 18 has an increased thickness in the region of the bores 78 for anchoring the outgoing ten-sion elements 12' by means of the wedges 23 so that a support surface 100 is formed with which the radially outer part of the anchoring disc 18l' abuts against the abutment member 19 , . , with the interposition of the shims 75 pro~ided for the possible release of the tension~
~1 !
In this embodiment, since the anchoring points for the ; outgoing tension elements 127 1 are no longer accessible after 1, the installatlon of the anchoring disc 18'' and the tensioning of the incoming tension elements 12l, it must be possible to i !
subsequently insert the outgoing tension elements 12l and to anchor them securely.- Accordingly~ the bores 78 are extended 1l !
Il from the frusto-conical section, arranged for the insertion of ~
- ~',,1 ~i -39-l~V~)~5~
; the wedges, toward the abutment number 19, by a cylindically-shaped widened section 101 in which a pressure spring 102 is arranged bearing against the surfaces of the wedges. A sleeve 103 bears against the free end of the pressure spring 102 and 1~ !
this sleeve is held in place by a snap ring 104 insertable i into an annular groove 105, note Figure 21. In this manner, the wedges 23 can be fastened in position.
When a tension element 12 " is being inserted, the pres-sure spring 102, can be compressed somewhat so that the wedges can be opened permitting the tension elements to pass through them. It is, however, assured by the pressure spring that the inserted strand is securely held by the wedge to prevent any retreating motion. The space formed by the widened section 101 of the bore 78 is filled with the corrosion-protection mass, the corrosion-protection mass 21 can be subsequently injected through a tubular opening 106 accessible on the out-side of the anchoring disc 18'.
'. I
il If, as indicated ln Figure 1, a tension member 10 runs along a path with a number of changes in direction points, then apart from the anchoring regions, the change in direction regions are designed in~ a specific manner so that a smooth ~: i transition of the change in direction forces is effected. One I I ' embodiment for such a change in direction point is illustrated i4 F~igure 22, partly ln axial section and partly in side view.
The tubular envelope for the tension member 10 in the region of the change in direction point is formed by the con-~3~
tlnuously pre-bent steel tube 110, preferably in the shape of a circular arc, which is capable of transferring the change in direction fcrces at the inner side of the curvature to the structural member, in Figure 22, the pilaster member 8. Steel tube 110 is either encased in the concrete of the pilaster member or, if it is to be axiall~ movable, with respect to the pilaster member, it is placed in a ~ormwork tube encased in the concrete.
'.
In the region of the change in direction point, the ten-sion elements must be arranged in an orderly manner, whereby spacers 112 are provided in this region which have openings through which the tension elements 12 extend. For the instal-. 1 .
lation of the spacers 112, there are several possibilities,installation intermediate spacers are allowed to remain at the change in direction points in the tubular envelope or in the sheathing tube 16 in order to stop the tension elements 12 during the pushing-in operation and to be able to thread them into appropriate openings in the spacer, or to install the spacers in another manner for subsequently moving them into the predetermined position at the change of direction point by axial displacement along the tension member or together with :
¦ the tension member.
To provide a smooth transition of the change of direction forces in the region of the change in direction points during tensioning of the tension member~ 10, the region of the curved ~.
^"` ~L3~
sheathiny tube 110 can, before the tensioning, be injected with hardenable material 22, for instance, cement mortar. For this purpose, the sheathing tube is sealed at both of its ends. The sealing action can be effected by insert pieces 114, constructed similar to the anchoring pot 20, note Figure 5. The insert pieces 114 are placed into the sheathing tube from the ends and have a base provided with openings for pass-ing the tension elements through them. The hollow space formed by the insert pieces is to be filled with a hardenable material, such as cement mortar. At one end, an injection hose 115 proiects into the curved sheathing tube and a venting tube or opening is provided at the other end so that any open vo]ume remaining within the sheathing tube 110 and around the sheathing ducts 13 of the strands 12 is filled with the harden-able material, that is, cement mortar. After the material has ;I hardened, the tension elements remain axially movable within their sheathing ducts 13 and can be tensioned. The strands 12 wlth the sheathing ducts 13 can for additional protection also extend through separate guidance tubelets formed of plastics material along the length of the change in direction regionO
In a simiLar manner lt is also possible beforehand to inject the sheathing tube with previously installed spacers and guidance tubelets and to position it in the prefabricated i! state.
, Finally, it is possible to provide a smooth redirection of the tension elements 12 at the chan~e in direction point so , i I
' -42-` ~3~8~
that spacers 112 formed of a plastic material are arranged in a sealed manner next to one another with aligned openings~
The described placement of the spacers assumes segmental injection of the entire cavity within the tubular sheathing.
To be able to fill the entire cavity after tensioning of the tension member, it is also possible to design the spacers in such a way and from such a material that they can carry the change in direction forces developed during the tensioning step and thus transmit the forces to the structural member.
This can be achieved if the spacers are formed of metal, such `I
as cast ironO In addition to passageways for the tension elements, the spacers must also provide passages .for the in-jected hardenable material.
~; i ., .
The connection of the curved sheathing tube 110 with the ~' adjacent parts of the sheathing tube 16 can, while bridgingover the intermediate spacers, take place in the manner described in connection with Figure 5, by sleeves and hose Il connectors, and also by means of the bolt-connected flanges .l described in Figure 11.
~While speclflc embodiments of the inventlon have been .i shown and described in detail to lllustrate the application of the inventive principIes, it will be understood that the invention may be embodied otherwise without departing from li such principles.
lll ~ -43-
Claims (43)
1. Corrosion-protected tension member, such as a tendon for prestressed concrete with post-tensioning, comprising at least one axially extending tension element, such as a steel rod, wire or strand located within a tubular envelope, and with an anchoring device at each end thereof, said tension element has an anchor region where is connected to said anchoring device and a free region extending between the anchor regions, said tubular envelope comprises a sheathing tube in the free region of said tension member connected in the anchor region to said anchoring device, said tubular envelope enclosing an open space around said tension element and said open space filled with a plastically deformable corrosion-protection mass at least in the region directly adjacent to said anchoring device, wherein the improvement comprises that said tension member comprises a plurality of said axially extending tension elements and each said tension element is located within a separate sheathing duct formed of a plastics material with a space located within said sheathing duct around said tension element and with said space within said sheathing duct filled with a plastically deformable corrosion-protection mass, said open space within said sheathing tube exteriorallly of said sheathing ducts and extending between the anchor regions being filled with a hardenable material while said open space in said anchor regions being filled with the plastically deformable corrosion protection mass.
2. Corrosion-protected tension member, as set forth in claim 1, wherein said tubular envelope in the anchor regions comprises an anchoring tube located within an opening in an abutment member and extending from said abutment member toward the free region of the tension member, an anchoring pot located within said anchoring tube and spaced inwardly therefrom and forming therebetween an annular space, said anchoring pot comprises a base at its end more remote from said abutment member having a plurality of openings corresponding to the number of said tension elements, said anchoring pot has a flange extending outwardly at its opposite end from said base and an annular space encircling said anchoring pot at said flange, and said anchoring pot being filled with a plastically deformable corrosion-protection mass.
3. Corrosion-protected tension member, as set forth in claim 2, wherein an anchoring disc bears against said abutment member on the opposite side of said abutment member from the free region and said tension elements extending from said anchoring pot through openings in said anchoring disc, and at least one injection opening and one venting opening connected to said annular space for charging hardenable material therein.
4. Corrosion-protected tension member, as set forth in claim 3, wherein said anchoring tube extends into a central opening through said abutment member and said central opening forms an annular shoulder, said anchoring tube has an outwardly directed flange located within the central opening in said abutment member bearing against the annular shoulder therein.
5. Corrosion-protected tension member, as set forth in claim 4, wherein a sealing ring formed of an elastic material is located between said flange on said anchoring tube and said annular shoulder in the central opening through said abutment member.
6. Corrosion-protected tension member, as set forth in claim 5, wherein said anchoring tube has an end at which said flange is located within the central opening in said abutment member and the end of said anchoring tube having protuberances spaced around its circumference with said protuberances bearing against said flange on said anchoring pot.
7. Corrosion-protected tension member, as set forth in claim 6, wherein said anchoring disc has an axially extending tubular extension extending from a surface of said anchoring disc facing said abutment member said tubular extension being telescopically inserted into said anchoring pot.
8. Corrosion-protected tension member, as set forth in claim 7, wherein said anchoring tube widens in a trumpet-like manner in the direction toward said anchoring disc.
9. Corrosion-protected tension member, as set forth in claim 8, wherein an intermediate layer formed of at least one of an elastically deformable material and a plastically deformable material, located between the inner surface of said anchoring tube and the adjacent tension elements in the region of the trumpet-like shape anchoring tube for affording smooth transition of change in direction forces of said tension elements.
10. Corrosion-protected tension member, as set forth in claim 9, wherein said intermediate layer is a ring bearing against the inner surface of said anchoring tube.
11. Corrosion-protected tension member, as set forth in claim 9, wherein at least said tension elements located adjacent said anchoring tube are enclosed within a covering sleeve formed of a plastics material.
12. Corrosion-protected tension member, as set forth in claim 9, wherein for relatively short said tension elements, the length of said anchoring pot is selected so that with any changes in length of said sheathing ducts due to temperature differences, the ends of said sheathing ducts do no separate outwardly from said anchoring pot.
13. Corrosion-protected tension member, as set forth in claim 9, wherein for comparatively long said tension elements, said plastics material sheathing ducts are secured within said anchoring pot for displacement of said sheathing ducts out of said anchoring pot by enlarging the circumferences of said sheathing ducts.
14. Corrosion-protected tension member, as set forth in claim 13, wherein said anchoring tube is connected with said sheathing tube in the free region of said tension member.
15. Corrosion-protected tension member, as set forth in claim 14, wherein an expansion joint is provided along the axial length of said tension member for compensating for length changes due to temperature differences wherein said sheathing tube has a butt-joint in the free region with an external sleeve enclosing the butt-joint and extending therefrom in both directions and having one end secured to said sheathing tube.
16. Corrosion-protected tension member, as set forth in claim 1, wherein the hardenable material filled into the open space between said sheathing ducts and said sheathing tube includes reinforcement.
17. Corrosion-protection tension member, as set forth in claim 1, wherein at least one of said anchoring devices provides a coupling point for coupling tension elements extending from both sides of said anchoring device, said anchoring device comprises an anchoring disc abutting against said abutment member and having first bores for anchoring incoming tension elements from one side of said anchoring disc and second bores for anchoring outgoing tension elements located on the other side of said anchoring disc and in the axially extending region of said outgoing tension elements spaced from said anchoring disc a sealing washer defines one end of the open space formed by said tubular envelope with openings in said sealing washer for the passage therethrough of at least said outgoing tension elements and the open space between said sealing washer and said anchoring device is filled with a plastically deformable corrosion-protection mass.
18. Corrosion-protected tension member, as set forth in claim 17, wherein said tubular envelope about said outgoing tension elements comprises an axially extending casing in the region adjacent said anchoring device and said casing is detachably connected to said anchoring device and to said sheathing tube in the free region of said tension member spaced from said anchoring device.
19. Corrosion-protected tension member, as set forth in claim 18, wherein said anchoring disc has a radially inner central region and a radially outer region around said central region, said bores for anchoring said incoming tension elements being located in the central region and said bores for anchoring said outgoing tension elements being located in said outer region.
20. Corrosion-protected tension member, as set forth in claim 19, wherein said casing for said outgoing tension elements comprise a first and a second axially extending section with each of said sections having a different diameter.
21. Corrosion-protected tension member, as set forth in claim 20, wherein each of said different diameter sections of said casing is separate from the other.
22. Corrosion-protected tension member, as set forth in claim 21, wherein said separate sections of said casing are detachably connected together.
23. Corrosion-protected tension member, as set forth in claim 22, wherein said sections of said casing are displaceable relative to one another in a telescopic fashion.
24. Corrosion-protected tension member, as set forth in claim 20 wherein a sealing washer is arranged at a point located at the connection between the separate sections of said casing.
25. Corrosion-protected tension member, as set forth in claim 24, wherein said sealing; washer is detachably connected with said casing.
26. Corrosion-protected tension member, as set forth in claim 25, wherein said sealing washer is formed as a spacer for said tension elements passing therethrough and said sealing washer being located at a change in direction point of said tension elements for absorbing change in direction forces resulting from the change in direction of said tension elements.
27. Corrosion-protected tension member, as set forth in claim 17, wherein said sealing washer is formed of two plates pressed against one another with openings through said plates for said tension elements and sealing rings located within the openings for effecting a sealing action around said tension elements.
28. Corrosion-protected tension member, as set forth in claim 18, wherein a redirection member is located at a change in direction point of said tension elements and said redirection member is ring shaped for absorbing change in direction forces oriented radially outwards at the location where the spacing between said tension elements commences to be increased.
29. Corrosion-protection tension member, as set forth in claim 28, wherein said redirection member is located within said casing and is detachably connected thereto.
30. Corrosion-protection tension member, as set forth in claim 29, wherein said sheathing tube enclosing said tension elements in the free region of said tension member extends into and through said redirection member in contact therewith and forms an intermediate layer located between said tension elements and said redirection member.
31. Corrosion-protected tension member, as set forth in claim 28, wherein an expansion ring is arranged for spacing the outgoing tension elements in the region of said redirection member.
32. Corrosion-protected tension member, as set forth in claim 31, wherein said expansion ring has an outer circumference forming a plurality of openings for securing said tension elements one of individually and in groups.
33. Corrosion-protected tension member, as set forth in claim 32, wherein said openings are separated by radially extending webs formed on said expansion ring.
34. Corrosion-protected tension member, as set forth in claim 33, wherein said expansion ring is formed as a sealing disc.
35. Corrosion-protected tension member, as set forth in claim 34, wherein said expansion ring is formed of a plastics material.
36. Corrosion-protected tension member, as set forth in claim 2, wherein said tension member has at least one change in direction point and said tubular envelope at said change in direction point is formed of a continuously bent tube extending along a circular arc.
37. Corrosion-protected tension member, as set forth in claim 36, wherein said tube extending along a circular arc is arranged to be axially movable relative to a structural member cooperating with said tension member.
38. Corrosion-protected tension member, as set forth in claim 37, wherein spacers are located within said circular arc tube in the region of the change in direction point with the diameter of said spacers being less than the inside diameter of said circular arc tube and having openings therethrough so that one of said tension element can extend through each of said openings.
39. Corrosion-protected tension member, as set forth in claim 1, wherein said corrosion protection mass is grease.
40. Corrosion-protected tension member, as set forth in claim 35, wherein said expansion ring is formed of polyethylene.
41. Corrosion-protected tension member, as set forth in claim 36, wherein said circular arc tube is a steel tube.
42. Method of installing a tension member, such as a tendon for prestressed concrete with post-tensioning where the tension member is located within a tubular envelope and extends between anchoring devices, the tension member has an anchor region in each of said anchoring devices and a free region extending between the anchor regions, comprising the steps of installing the tubular envelope in the anchor region and in any regions of change of direction of the tension member between the anchor regions, installing said tubular envelope as a plastics material sheathing tube in the free region of said tension member and leaving axially extending open spaces in the tubular envelope in the free region adjacent to the anchor regions, placing the tension member made up of a plurality of tension elements between the anchor regions and at least partially prestressing the tension elements, leaving an open volume within the tubular envelope outwardly of the tension elements, closing the axially extending open spaces in the tubular envelope for providing a continuous closed envelope, and injecting a hardenable material into the open volume within the tubular envelope.
43. Method, as set forth in claim 42 wherein providing a change in direction point in the free region between the anchor regions, and at the change in direction point filling the cavity between the tubular envelope and the tension elements with a hardenable material prior to tensioning said tension elements.
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEP3708067.9 | 1987-03-13 | ||
DE3708067 | 1987-03-13 | ||
DEP3734954.6 | 1987-10-15 | ||
DE19873734954 DE3734954A1 (en) | 1987-03-13 | 1987-10-15 | Corrosion-protected tensioning member, in particular stressing member for prestressed concrete without pretensioning, and process for its installation |
DEP3801451.3 | 1988-01-20 | ||
DE19883801451 DE3801451C2 (en) | 1987-10-15 | 1988-01-20 | Corrosion-protected free tension member, primarily tendon for prestressed concrete without bond |
Publications (1)
Publication Number | Publication Date |
---|---|
CA1300855C true CA1300855C (en) | 1992-05-19 |
Family
ID=27195596
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA000561230A Expired - Lifetime CA1300855C (en) | 1987-03-13 | 1988-03-11 | Corrosion protected tension member for use in prestressed concrete and method of installing same |
Country Status (5)
Country | Link |
---|---|
US (1) | US4878327A (en) |
JP (1) | JPH0776473B2 (en) |
CA (1) | CA1300855C (en) |
CH (1) | CH676617A5 (en) |
IT (1) | IT1219102B (en) |
Families Citing this family (33)
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US5231931A (en) * | 1992-01-23 | 1993-08-03 | J. Muller International | Rapid transit viaduct system |
US5386782A (en) * | 1992-01-23 | 1995-02-07 | J. Muller International | Rapid transit viaduct system with central platform station |
JPH07103644B2 (en) * | 1992-04-27 | 1995-11-08 | 鋼弦器材株式会社 | TENSION MATERIAL PROTECTIVE DEVICE AND ITS INSTALLATION METHOD |
US5749185A (en) * | 1996-04-25 | 1998-05-12 | Sorkin; Felix L. | Method and apparatus for an intermediate anchorage of a post-tension system |
DE19634682C2 (en) * | 1996-08-28 | 1999-07-08 | Dyckerhoff & Widmann Ag | Seal for delimiting areas to be filled with a sealing compound on a bundle tension member for prestressed concrete |
NO322852B1 (en) * | 2000-05-31 | 2006-12-11 | Aker Kvaerner Subsea As | Termination of tension body |
US5839235A (en) * | 1997-08-20 | 1998-11-24 | Sorkin; Felix L. | Corrosion protection tube for a post-tension anchor system |
JP2001032211A (en) | 1999-05-17 | 2001-02-06 | Anderson Technology Kk | Box girder structure of bridge having external cable, and building method of box girder |
FR2794484B1 (en) | 1999-06-03 | 2001-08-03 | Freyssinet Int Stup | DEVICE FOR ANCHORING A STRUCTURAL CABLE |
FR2798410B1 (en) | 1999-09-15 | 2001-11-23 | Freyssinet Int Stup | ANCHORING DEVICE FOR ATTACHING A STRUCTURAL CABLE TO A CONSTRUCTION ELEMENT |
IT1313918B1 (en) * | 1999-10-12 | 2002-09-26 | Sergio Zambelli | DEVICE FOR THE CONNECTION OF A BEAM TO PILLARS, OR SIMILAR SUPPORTING ELEMENTS, FOR THE CONSTRUCTION OF BUILDINGS, |
US6470636B1 (en) * | 2000-08-07 | 2002-10-29 | Dallas R. Rose | Detensioning apparatus for releasing a chuck on a prestressed strand |
AU2002213873A1 (en) * | 2000-09-12 | 2002-03-26 | Max Boegl Bauunternehmung Gmbh & Co. Kg | Travel way support |
DE10062227A1 (en) * | 2000-12-13 | 2002-06-20 | Dyckerhoff & Widmann Ag | Method for installing and tensioning a freely tensioned tension member, in particular a stay cable for a stay cable bridge, and anchoring device for carrying out the method |
PT1227200E (en) * | 2001-01-29 | 2008-09-15 | Vsl Int Ag | Device and method for anchoring one end of a stay to a base |
DE20205149U1 (en) * | 2002-04-03 | 2002-07-04 | Dywidag Systems Int Gmbh | Corrosion-protected tension member, especially stay cable for a stay cable bridge |
CN1296590C (en) * | 2002-07-16 | 2007-01-24 | 同济大学 | Outer prestress system and its construction process |
US7055288B2 (en) | 2003-04-16 | 2006-06-06 | Coogan Donald B | Pre-stressing sheath |
DE20311950U1 (en) * | 2003-08-02 | 2004-12-09 | Dywidag-Systems International Gmbh | Corrosion-protected tension member, in particular tendon for prestressed concrete |
US20080134598A1 (en) * | 2006-12-07 | 2008-06-12 | Anthony Rizzuto | Unbonded Post-Tension Strand Protector |
US8769882B2 (en) * | 2010-06-07 | 2014-07-08 | Hardwire, Llc | Protection system for structural members such as cables |
US11273527B2 (en) * | 2010-09-24 | 2022-03-15 | Bright Technologies, Llc | Method of terminating a stranded synthetic filament cable |
FR2968681B1 (en) * | 2010-12-08 | 2015-05-29 | Soletanche Freyssinet | DEVICE FOR THE DEVIATION OF A STRUCTURED CABLE, SUCH AS A HAUBAN, AND A WORK THUS EQUIPPED |
RU2566541C2 (en) | 2011-04-15 | 2015-10-27 | Солетанш Фрейсине | Protection of multistrand rope ends |
WO2012140463A1 (en) * | 2011-04-15 | 2012-10-18 | Soletanche Freyssinet | Anchoring device for a multi-tendon cable |
JP5960004B2 (en) * | 2012-09-14 | 2016-08-02 | 前田建設工業株式会社 | Prestressed concrete cable tension estimation method |
GB2514621B (en) * | 2013-05-31 | 2020-04-15 | Vsl Int Ag | Cable anchorage |
US10578191B2 (en) * | 2014-04-22 | 2020-03-03 | Bright Technologies, Llc | Advanced stranded cable termination methods and designs |
CN104405135B (en) * | 2014-10-31 | 2016-06-08 | 中国建筑股份有限公司 | The spatial positioning constructional method of dome structure presstressed reinforcing steel |
EP3529423A4 (en) * | 2016-10-20 | 2020-06-24 | SRG IP Pty Ltd | Improved connector for use in forming joints |
IT201800005437A1 (en) * | 2018-05-16 | 2019-11-16 | FIXING DEVICE FOR TIE ROPES | |
AT521553B1 (en) * | 2018-08-03 | 2023-02-15 | Sdo Zt Gmbh | Method and formwork for manufacturing a slab, and slab |
JP7191719B2 (en) * | 2019-02-22 | 2022-12-19 | オリエンタル白石株式会社 | PCaPC floor slab with double-tube structure sheath |
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US3399434A (en) * | 1965-09-27 | 1968-09-03 | William F. Kelly | Anchors for stressed cables |
US3803788A (en) * | 1968-06-19 | 1974-04-16 | P Artmann | Building construction and process for producing structural elements for such construction |
US3935685A (en) * | 1974-06-07 | 1976-02-03 | Howlett Machine Works | Anchor member and method of forming same |
FR2277953A1 (en) * | 1974-07-09 | 1976-02-06 | Stup Procedes Freyssinet | FREE TENSIONS IN THE FORM OF TENSIONED STEEL REINFORCEMENT |
DE2657202C3 (en) * | 1976-12-17 | 1979-05-23 | Dyckerhoff & Widmann Ag, 8000 Muenchen | Coupling point for a post-tensioning bundle tendon for prestressed concrete |
DE2753112C3 (en) * | 1977-11-29 | 1981-01-22 | Dyckerhoff & Widmann Ag, 8000 Muenchen | Anchoring of a tensioned tension member for high loads in a concrete component, e.g. a stay cable of a cable-stayed bridge |
DE8002045U1 (en) * | 1980-01-26 | 1980-04-30 | Dyckerhoff & Widmann Ag, 8000 Muenchen | RECOVERABLE SHUTTERING PART FOR THE ANCHORING AREA OF A TENSION LINK IN A CONCRETE COMPONENT |
JPS5755851U (en) * | 1980-09-17 | 1982-04-01 | ||
DE3138807C2 (en) * | 1981-09-30 | 1986-10-30 | Dyckerhoff & Widmann AG, 8000 München | Free tensioned tension member, especially stay cable for a stay cable bridge |
DE3224702C2 (en) * | 1982-07-02 | 1986-01-16 | Dyckerhoff & Widmann AG, 8000 München | Device for anchoring and coupling a bundle tendon for prestressed concrete |
JPS59141660A (en) * | 1983-02-02 | 1984-08-14 | 株式会社大林組 | Composite unbonded pc steel twisted wire |
DE3437107A1 (en) * | 1984-10-10 | 1986-04-10 | Dyckerhoff & Widmann AG, 8000 München | TIE LINK, ESPECIALLY SLOPED ROPE FOR A SLIDING ROPE BRIDGE |
DE3438865C1 (en) * | 1984-10-24 | 1986-04-03 | Dyckerhoff & Widmann AG, 8000 München | Wedge anchorage for the tensioning side of a single tendon for a prestressed concrete component |
-
1988
- 1988-03-03 CH CH822/88A patent/CH676617A5/de not_active IP Right Cessation
- 1988-03-11 JP JP63056452A patent/JPH0776473B2/en not_active Expired - Fee Related
- 1988-03-11 IT IT67207/88A patent/IT1219102B/en active
- 1988-03-11 CA CA000561230A patent/CA1300855C/en not_active Expired - Lifetime
- 1988-03-14 US US07/167,631 patent/US4878327A/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
IT8867207A0 (en) | 1988-03-11 |
JPS63236849A (en) | 1988-10-03 |
CH676617A5 (en) | 1991-02-15 |
US4878327A (en) | 1989-11-07 |
JPH0776473B2 (en) | 1995-08-16 |
IT1219102B (en) | 1990-05-03 |
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