US3864776A

US3864776A - Prestressed post tension suspension bridge cable anchorage

Info

Publication number: US3864776A
Application number: US416092A
Authority: US
Inventors: Alfred Hedefine; Louis G Silano
Original assignee: Parsons Brinckerhoff Quade and Douglas Inc
Current assignee: Parsons Brinckerhoff Quade and Douglas Inc
Priority date: 1973-11-15
Filing date: 1973-11-15
Publication date: 1975-02-11
Anticipated expiration: 1992-02-11

Abstract

By prestressing a suspension bridge cable anchorage at a bearing plate and tensioning the cable strands at different points on the bearing plate, savings in the mass of concrete or scope of anchor rod in rock is obtained, saving labor and material. The anchorage is adapted to different cable strand configurations and facilitates suspension bridge construction and cable anchorage.

Description

United States Patent 1 1 Hedefine et a1.

1 1 PRESTRESSED POST TENSION SUSPENSION BRIDGE CABLE ANCHORAGE [75] Inventors: Alfred Hedefine, Sparta. N.J.; Louis G. Silano, Seaford. NY.

[73] Assignee: Parson, Brinckerhofi, Quade & Douglas, Inc., New York, NY.

[ 1 Feb. 11, 1975 2.132.269 10/1938 McHugh 14/21 2,914,783 12/1959 Hoyden 14/21 3.475.777 11/1969 Robinson 14/21 1548.432 12/1970 Durkee 14/21 Primary Examim'rNile C. Byers. Jr. Armrney. Agenl, or Firm-Auslander & Thomas [57] ABSTRACT By prestressing a suspension bridge cable anchorage at a bearing plate and tensioning the cable strands at different points on the bearing plate, savings in the mass of concrete or scope of anchor rod in rock is obtained, saving labor and material. The anchorage is adapted to different cable strand configurations and facilitates suspension bridge construction and cable anchorage.

34 Claims, 18 Drawing Figures PATENTEU FEB] sum 1 or a PATENTEDFEBI 1 ma SHEET U 0F 8 mIOE * PATENTEDFEBI 915 SHEET 5 OF 8 r 1 PRESTRESSED POST TENSION SUSPENSION BRIDGE CABLE ANCHORAGE The present invention relates to a prestressed post tension suspension bridge cable anchorage.

In the past, many efforts have been made to reduce the cost of both labor and material in the construction of suspension bridges without sacrificing structural strength.

The main cables of suspension bridges built since the beginning of the industrial era have been of three types: chains, eyebar and wire. Since the late 1920's important suspension bridges have used wire cables, which in turn have been of two types: parallel wire cables and helical wire strand cables.

From the bridge designers point of view, parallel wire cables are superior to cables made of helical wire strands. This is because straight, parallel laid wires deliver the full strength and modulus of elasticity of the steel, whereas strength and modulus are both reduced as a result of the helical placement of wires in conventional strands. Consequently, bridge cables of helical strand construction must have significantly greater cross-sectional area than those of parallel wire construction.

On the other hand, from the bridge erectors standpoint, strand-type cables are superior to the parallel wire type. Strands are readily erected and adjusted, with minimum equipment and manpower. But aerial spinning" of individual wires, the standard erection procedure for parallel wire cables, is a long, tedious and complex operation, requiring expensive and complicated equipment. For this reason, helical strand cables can be used economically on small to medium-size suspension bridges, in spite of the resulting increased quantity of permanent material.

Parallel wires, rather than helical wires, could be shop manufactured and socketed, and properly packaged for shipment, then it would be possible to construct parallel wire bridge cables using the simple erection techniques applicable to strand-type cables. A cable made of shop-built parallel wire strands would combine all of the erection advantages of strand-type cables with the superior in-place characteristics of parallel wire cables.

Whether the cable was spun, parallel or helical, the cable required an anchorage.

The larger the bridge, the heavier the anchorage mass that was required to hold the cable and cable strands securely, and further be able to withstand the stress and strain of the suspension bridge under use and weather conditions.

Anchorages usually were in concrete anchorage foundations, in or out of the water, or in bed rock. In either case, the amount of concrete required for the anchorage foundation in or out of water was dictated by the load calculated for the suspension bridge or the depth of anchorage foundation in bed rock was dictated by the same consideration.

According to the present invention, an anchorage foundation of concrete or in bed rock is provided, that enables a suspension bridge cable to be anchored using a minimum requirement of concrete or a minimum depth or lesser depth of anchorage in bed rock, size for size and stress for stress, of comparable bridges constructed in the past with a saving of time and labor because of ease of construction.

The present invention is at the same time adapted for use with parallel spun cable strands, or helical cable strands, or prefabricated parallel wire or strands.

As an incident to the present invention, some applications of the present invention enable faster anchorage of the strands and free inspectability of the cable anchorage, the bearing plates and the strands and easy alignment of the strands with a minimum of adjustment or precalculation.

Anchorages of the past have used frames similar to that of the present invention. By so doing, the difficult task of aligning the strand splay to the anchorage was made less difficult and a solid anchorage was made at a rear bearing plate such as shown in U.S. Pat. No. 3,548,432 to Durkee, U.S. Pat. No. 3,475,777 to Robinson even provided anchor rods through the anchor block which wire tensioned the bearing plate and somewhat made alignment of the strands and rods easier.

Now according to the present invention alignment is made even simpler and prestressing by post tensioning of the bearing plates may be used to the point of reducing the amount of concrete necessary to go into the anchorage necessary to support the weight and stress of the suspension bridge and the strands substantially self aligned to the splay in a compact construction which in itself may save concrete.

Although such novel feature or features believed to be characteristic of the invention are pointed out in the claims, the invention and the manner in which it may be carried out may be further understood by reference to the description following and the accompanying drawings.

FIG. I is a typical suspension bridge with cable anchorage in the water.

FIG. 2 is a section of a concrete anchorage in water.

FIG. 3 is a frame of anchor cylinders free of concrete.

FIG. 4 is a partial front elevation of the front bearing plate of FIG. 3.

FIG. 4a is a reduced partial elevation of the rear bearing plate of FIG. 3.

FIG. 5 is a partial sectional plan view of a bearing plate such as exemplified in FIG. 4 including cylinders and structure.

FIG. 6 is a cut-away view of the front and rear bearing plates, an anchor cylinder and a tensioning rod.

FIG. 7 is a cut-away view behind the bearing plate showing a strand shoe and tension rods.

FIG. 7a is a fitting for FIG. 7 for a prefabricated strand anchorage.

FIG. 8 is a partial front elevation of a bearing plate and beams for a prefabricated strand anchorage and tension rods.

FIG. 8a is a partial elevation of the rear bearing plate of FIG. 8.

FIG. 9 is a detail of a bearing plate beam, the rod and strands shimmed.

FIG. 10 is a partial plan section of a beam with details of tension rods and attached strands.

FIG. 11 is an isometric cut-away view of a base, connected strands and bearing plate against the concrete anchorage.

FIG. lla is an exploded section view of a socket anchor of FIG. 11.

FIG. llb is a closure ring for the socket anchor of FIGS. 10 and I1.

FIG. 12 is a perspective view of an alternate strand shoe for prefabricated strands such as may be used with the bearing plate of FIG. 7.

FIG. 13 is a partial section of a bearing plate and rock anchorage of the present invention.

Referring now to the figures in greater detail, where like reference numbers denote like parts in the various figures. v

The suspension bridge as shown in FIG. 1 is suspended by cable 11 anchored in concrete anchorages 12 in the mass of anchor blocks 13.

The strands 46 of the cable 11 are fastened to a hearing plate 15, such as shown in FIG. 4, at one end of an anchor block 13.

A rear bearing plate 16 is shown reduced and cut away in FIG. 4a, which is at the other end of the anchor block '13.

The bearing

plates

15, 16 are usually part of a frame 17 which supports the anchor cylinders 18. As can be seen in FIG. 6 a cylinder 18 is preferably held to the bearing

plates

15, 16 by threading sleeves 19 extending from the bearing

plates

15, 16.

The enormity of dimension of parts may be hard to conceive from the drawings.

It is oftentimes necessary to couple the anchor cylinders 18 in order to achieve sufficient length by a coupling sleeve 20 as shown in FIG. 6.

The frame 17 is provided with, among other things, channel irons 21 and cylinder supports 22 to hold the anchor cylinders 18 in proper position.

Rods 42 are set up in the anchor cylinders 18 and ultimately tightened against the bearing

plates

15, 16 held by nuts 24, usually with washers 25 between the nuts 24 and

bearing plates

15, 16, although on occasion shims may be used.

The front bearing plate 15, as seen in FIG, 4 and 5 includes a series of spaced openings 26 through which the rods 42 may pass as shown in FIG. 6. The rear bearing plate 16 includes a counterpart of the openings 26 in front bearing plate 15.

The front bearing-plate 15 includes a secondary system of openings 27 which have a regular flare tapering to a greater width at the front of the front bearing plate 15.

In FIG. 5, washers 28 having rounded concavities 32 are provided behind the flared openings 27 to receive stud bolts 29 as shown in FIG. 7. In FIG. 7, some concrete 30 is shown, as will be more fully discussed later.

In FIG. 7 the stud bolts 29 are held by rounded nuts 31 which coincide with a concavity 32 in the washers 28. The stud bolts 29 extend through a shoe 33 shown in section in FIG. 7. The stud bolts 29 are held to the shoe 33 by nuts 34. In FIG. 5, covers 28a for the washers 28 and nuts 31 are shown.

The shoe 33 as shown in FIG. 7 is a section ofa double shoe capable of holding one strand 46 of cable 11 wire on each side of the bolts 29. Each strand 46 is made up of several wires.

The shoe 33 is similar to the structure used in the construction of spun strands.

, A cover 28a, as shown in FIG. 7, normally protects the nuts 31 and bolts 29 and round washers 28 from poured concrete 30. The covers 28a may be grouted upon completion of the bridge 10.

In FIG. 7a an alternate construction of strand socket 36 is shown. The construction of the socket 36 is one form of socket useable with prefabricated strands which do not have to be spun. The socket 36 may be used with the bearing plate 15.

As shown in FIG. 8, a bearing plate 40 has a series of openings 41 adapted to receive rods 42 which are shown held to the beams 43 by nuts 44. The other ends of the rods are held to the rear bearing plate 45 in the same manner as shown in FIG. 6. The strands 46 are only shown in section in FIGS. 8 and 9.

In FIG. 9 a detail of a beam 43 is shown. Washer plate 47 closes the U channels 48 and held by the nuts 44.

The strands 46 pass through the U channels 50 and as can be seen in FIGS. 10 and 11, are locked into the beams 43. The rods 42 pass through the beam 43, the washer plate 47 and the bearing plate 40 and are fastened to the front of the beam 43.

The beam 43 as shown in FIGS. 10 and 11 has a heavy forward flange 51, a middle flange 52, a rear flange 53, all of which may be joined by an intermediate webbing 54. The middle supports 52 are heavy to stand great stress and include U channels 56 into which the strands 46 with sockets 57 are held.

The beam 43 also includes two

support walls

58, 59 which brace the middle flange 52 crossing beam 43 with part of its thickness to brace the rear flange 53.'A central support wall 60 also braces the middle flange 52.

Thinner cross walls 61 span the beam 43 from the forward flange 51 to the rear flange 53 and serve as a channel for the rods 42 which pass between the

walls

61 and 58, S9.

The strands 46 may be held by a keeper 62 as shown in FIG. 9.

The rods 42 pass through anchor cylinders 18 which are held to the bearing plate 40 by threaded sleeves 19. While not shown, the anchor cylinders 18 are also held by threaded sleeves 19 at the rear bearing plate 45.

The sockets 57 round ends 63 are preferably rounded as shown cut away in FIG. 10.

Engaging a strand in a beam 43 is easily effected by just placing the strand 46 and socket 57 through the

U channels

50, 56. A split washer 64 having

half sections

65, 66 is then placed about the rounded end 63 of the socket 57 and held in position by a keeper ring 67 as shown in FIGS. 11, 11a and 11b. Adjustment of the strands 46 is effected by the use of fills 68 and shims 69. The use of fills 68 and shims 69 is illustrated in FIG. 11.

In FIG. 12 a strand shoe 70 is shown. The strand shoe 70 is particularly adaptable for use with bearing plate 15 of FIG. 4. Stud bolts 29 extend from the bearing plate 15 and hold the strand shoe 7 with the nuts 34.

Prefabricated strands 46 with their sockets 72 are engaged in the U channels 73 and tightened by use of the nuts 34 to take up any slack.

The cable anchorage 80, as shown in FIG. 13, is an anchorage to the mass of bed rock 81. Rods 82 are anchored deep into bed rock 81 mass by means well known in the art. The rods pass through the bearing plate 83 which is grouted with concrete 84 so that the interface between the bearing plate 83 and rock 81 and concrete 84 is smooth.

The rear of the bearing plate 83 is preferably provided with cover 28a to protect the stud bolts 29, washer 28 and round nut 31 so that they can be properly adjusted.

Thus far, the hardware has been described in its physical detail. Much of it is old in the art and might not show any significance.

In suspension bridges the old method of spinning cable is not entirely abandoned even though it is generally slow and the labor is expensive.-

Great savings in labor and money have been made by erecting suspension bridges by unrolling and setting prefabricated cable strands.

The present invention adds a new dimension to suspension bridge building by adapting a new advantage to the construction of the cable anchorage whether in rock or concrete with old-fashioned spun cable or with the newer prefabricated cable.

The frame 17 with its anchor cylinder 18 and

bearing plates

15, 16 is encased in concrete as can be seen in FIG. 1, where the anchor block 13 has hardened to concrete.

After the concrete has fully hardened, the rods 42 are tightened against the bearing

plates

15, 16 with the nuts 24 bearing on the bearing

plates

15, 16 and are prestressed to a stress about a third greater than the tension the cable 11 and strands 46 are expected to have to bear.

The strands 46 then are anchored to the

front bearing plates

15, 40. 83 by various means such as shown in FIGS. 5, 7, 7a, 9,10, 11, 12 and 13.

In the completed suspension bridge 10, usually a smaller amount of concrete block 13 is required to form the cable anchorage 12. The post tensioning of the anchor block 13 is effected by tensioning the bearing

plates

15, 16 by tightening the nuts 24 on the rods 42 against the bearing

plates

15, 16, such as shown in FIGS. 6, 7,10 and 11. When the strands 46 are in place the resultant stress on the anchor block 13 is the differential of the normal tension from the cable 11, strands 46 and the stress of post tensioning, thus relieving the anchor block 13 of most of the post tensioning stresses. With the present invention, the rods 42 and cylinders 18 may be closely set, saving space and concrete. The strands 46 are quickly and easily mounted. The prestressing by post tensioning of the anchor block 13 is made simple, saving labor and time.

In the past, such as shown in U.S. Pat. No. 3,475,777, some ease of construction was achieved by attaching the strands to a post-tensioned rod, post tensioned to the anchor block. Such expedient and the coupling means may have facilitated the building of suspension bridges but it has the complications of bore-sight align ment and it overlooked the importance of pretensioning the concrete block before attaching the strands 46. All the tensions of each strand of the US. Pat. No. 3,475,777 depend directly upon each of the individual,

post-tensioning rods

42, 82.

The strands 46 of the present invention are each directly or indirectly connected to the

front bearing plates

15, 40, 83 or bear upon it in some way as are the

rods

42, 82, thus any stress on strands 46 or

rod

42, 82 bears on the

entire bearing plate

15, 40, 83 rather than on any one particular rod 42. The massiveness of the bearing

plate

15, 40, 83 is better able to distribute a particular stress than a particular rod.

The concrete anchorage 12, as shown in FIG. 2 usually has a manhole 90 and ladder 91 for access to the bearing plate 16. Inspection and maintenance is facilitated by this. If the rods 42 are ungrouted as yet, or ungrouted, repair may be facilitated.

In FIG. 3, parts of the frame 17 are shown with the concrete faces 100, 101, 102, 103, ultimately to form the concrete block 13 flush with the bearing

plates

15, 16. In FIG. 4, the openings 26 in the bearing plate 15 are for the rods 42 to protrude through. As seen in FIG. 6, a rod 42 is shown in the bearing

plates

15, 16 held by washers 25 against the bearing plates 15, I6 and tightened by nuts 24.

Inside the bearing plates l5, 16 are threaded sleeves 19 which are anchor cylinder 18 may be screwed into to join the front and

rear bearing plates

15, 16. A coupling sleeve 20 may join parts of the anchor cylinder 18 when it is in more than one piece.

The openings 27 are flared wider toward the front of the bearing plate 15.

As can be seen in FIG. 7, a washer 28 with a concavity 32 and a nut 31 is inside the bearing plate 15 where stud bolts 29 are held by rounded nuts 31. The inside of the bearing plate 15 of the stud bolt 29 construction is protected by a cover 28a so that when the concrete block 13 is poured, this portion will be free to manipulate.

When the bearing plate 15 is set up; it is preferable to install the studs 29 and nuts 31 in the washers 28 so that the strands 46 may be attached after the concrete has been poured over the frame 17 and the anchor block 13 has been prestressed.

The alignment and adjustment of the sockets 36 or shoes 33, to get proper splay, is easily done from a flat bearing plate 15 by the latitude of movement the studs 29 have in the flared openings 27 in the bearing plate 15 which appose the cable 11 and the splay of the strand 46.

Socket covers 28a, as shown in FIG. 5, may cover the stud 29, washer 28, but 31 construction. The socket covers 28a may be used whether or not the open area of the socket cover 28a is grouted when the strands 46 are fully placed and adjusted.

The bearing plate 40 is relatively thin. The support for prestressing and post tensioning is found primarily in the beams 43.

Rods 42 pass through the bearing plate 40 openings 41 through the channels in the beam 43 passing through a U channel 111 at the bearing plate 40 and U channel 48 at the front of the beam 43.

The prestressing is done by tightening the nuts 44 on the rods 42 in the front of the beam and nuts (not shown) on the bearing plate 45, or otherwise gripping the rods 42 by means known in the art.

Easy adjustment of tension and slack on the rods 42 and beam 43 is taken care of by tightening the nut 44 down on the washer 47 shown in FIG. 9.

Prefabricated strands 46 with sockets 57 are easily placed through the

U channels

50, 56 behind the middle flange 52, which is in an intermediate position in the beam 43, where they can be set so their round bottoms 63 fit into the rounded split washers 64, held in place by the keeper ring 67 and adjusted fills 68 and shims 69.

The stresses of post tensioning of the rods 42 and tensioning of the strands 46 are again divided to the beam 43 and the bearing plate 40.

Adjustment of the strands 46 under construction and in final use is facilitated by the ability of the socket 57 to move in the split washer and orient the strand 46 with room for movement provided by the U channels 50 which easily adjust for splay just as the flaring of the opening 27 permits the same type of adjustment.

In FIG. 12, the strand shoe 70 is another fitting useable with the bearing plate 13 of FIG. 7. The bearing plate is prestressed as heretofore discussed. The shoe 70 is held by studs 29 and nuts 34. The strands 46 are placed in the U channels 73 held in place by keeper plates 62, adjusted for splay and adjusted for length by tightening the nuts 34 and using shims 69, or by using means disclosed or known in the art.

Where solid bed rock is available for a cable anchorage, the advantages of the present invention are also available.

As is well known in the art, cable strands may be anchored to bed rock 81.

When rock is not solid, a concrete anchorage may be carved out of rock and filled with concrete. In such case, the teachings of the present invention may be applied.

Where bed rock 81 is available as shown in FIG. 13, the anchorage is to actual rock as distinguished from concrete. The techniques known in the art provide for drilling suitable holes in the rock 81, then securing rods 82.

According to the present invention, savings in labor and/or material and time may be achieved in the case of rock formations. It saves excavation and allows anchorage of the rods 82 more easily, often with less rods 82 or shorter rods 82, with less grouting in a rock mass capable of supporting the particular bridge being built.

As shown in FIG. 13, a rod 82 is secured by means known in the art. A bearing plate 83 rests flat against the jagged surface spaced by grout 84 between the rock 81 and plate 83.

A rounded washer 28, stud bolt 29 and round nut 31 allow the stud bolt 29 to be attached to a strand fitting. The rod 82 and other rods 82 (not shown) are stressed between the bearing plate 83 and the anchorage of the rod 82; the strands are tensioned as stated before, leaving greater stress on the rods 82.

The stresses are then balanced, with greater stress on the rock anchor and counterbalanced by the cable strand tensioning. Stresses are distributed throughout the bearing plate 83.

The cover 28a is for access. It may be left open or grouted when construction is complete.

Overall, when prestressing and post tensioning in concrete, according to the present invention, there is a good saving of concrete required to anchor the cable and a concommitant material cost and saving of labor because the anchorage 13 is constructable is a very compact space.

According to the present invention, the compactness of the anchorage l2 usually obviates the use of more concrete than is necessary to support the weight of the bridge 10 with a concommitant saving of labor.

By the same token, according to, the present invention,.when anchoring in bed rock 81, the savings comes in the rock excavation and material and labor, because of the simplicity of installation.

Whenever used herein, the phrase U-shaped channel refers to a slot, whether of parallel sides of angulated sides, shaped to receive its selected rod or strand. The bottom portion of said U-shaped channel does not necessarily have to be round.

Unless otherwise specified, specific shapes are not of the essence, where round, square or other shapes serve the same functional purposes.

The terms and expression which are employed are used as terms of description; it is recognized, though, that various modifications are possible.

Having thus described certain forms of the invention in some detail, what is claimed is:

1. In a suspension bridge a cable anchorage construction comprising an anchorage mass, a cable, said cable including at least one cable strand, a bearing plate apposed to said cable, at least one rod opening in said bearing plate, at least one rod, said at least one rod gripped at least at one of its ends remote from said bearing plate, the other end of said at least one rod extending through at least one bearing plate opening, means to fasten said at least one extending rod held bearing upon said bearing plate, means bearing upon said bearing plate to hold said at least one said cable strand, tightening means including said bearing plate and said at least one rod to stress said cable anchor mass, means clear of said at least one rod held bearing upon said bearing plate to retain at least one cable strand, and means to tension said at least one cable strand against said anchorage masss stress.

2. The invention of claim I wherein said anchorage mass is bedrock.

3. The invention of claim 2 wherein said at least one rod is held fastened in said bedrock.

4. The invention of claim 3 wherein said bedrock is stressed by tightening said at least one rod against said bearing plate.

5. The invention of claim 4 wherein said means to hold said cable strand includes means to orient said holding means to the splay of said at least one cable strand.

6. The invention of claim 5 wherein said means to hold said cable strand includes a protective cover.

7. The invention of claim 1 wherein said anchorage mass is substantially concrete.

8. The invention of claim 7 including a frame, a front bearing plate, a rear bearing plate, at least one anchor cylinder and at least one held rod bearing upon said front and rear bearing plate.

9. The invention of claim 8 wherein said front and rear bearing plates include at least one sleeve, said at least one anchor cylinder held by said sleeve.

10. The invention of claim 9 wherein said sleeve and at least one anchor cylinder are threaded.

11. The invention of claim 10 wherein said rear bearing plate includes at least one opening for at least one rod, said front bearing plate includes at least one opening for at least one rod and at least another opening for means to hold at least one cable strand.

12. The invention of claim 11 wherein said concrete mass is stressed by tightening said at least one rod against said concrete mass between said front and rear bearing plates.

13. The invention of claim 12 wherein said at least one cable strand is spun on a shoe, said shoe held to said front bearing plate by at least one stud bolt.

14. The invention of claim 13 wherein said at least one stud bolt is held to said front bearing plate by a rounded bottom nut.

15. The invention of claim 14 wherein said nut rests in a rounded washer.

16. The invention of claim wherein said opening in said bearing plate for said cable strand holding means is flared outward to the face of said front bearing plate.

17. The invention of claim 12 wherein said at least one cable is prefabricated and includes a socket.

18. The invention of claim 17 wherein said socket is held by at least one stud bolt.

19. The invention of claim 18 wherein said at least one stud bolt is held to said front bearing plate by a rounded bottom nut.

20. The invention of claim 19 wherein said nut rests in a rounded washer.

21. The invention of claim 20 wherein said opening in said bearing plate for said cable strand holding means is flared outward to the face of said front bearing plate.

22. The invention of claim 17 wherein said socket is T shaped.

23. The invention of claim 17 including a shoe having at least one U-shaped channel wider than said strand and having a socket wider than said U-shaped channel.

24. The invention of claim 8 wherein said bearing plate includes at least one beam adapted to interact with said bearing plate.

25. The invention of claim 24 wherein said beam includes a front flange and a rear flange and support means, at least one U channel in its front and rear flanges adapted to receive at least one rod at said front flange, means to hold said at least one rod on said front flange, at least one intermediate flange having a U channel apposed to a U channel in said front flange, and at least one cable strand narrower than said U channel with a socket wider than said U channel.

26. The invention of claim 25 wherein said means to hold said at least one rod includes at least one fill.

27. The invention of claim 26 further including at least one shim.

28. The invention of claim 27 wherein said at least one shim includes a U channel.

29. The invention of claim 28 wherein said at least one cable strand is prefabricated.

30. The invention of claim 29 wherein said cable strand includes at least one socket having a rounded portion facing the length of said strand.

31. The invention of claim 29 wherein said at least one socket is mounted in a rounded washer.

32. The invention of claim 31 wherein said rounded washer is split into more than one piece and adapted to be held together by a keeper.

33. The invention of claim 23 wherein said socket mounting includes at least one fill.

34. The invention of claim 33 further including at least one shim.

Claims

1. In a suspension bridge a cable anchorage construction comprising an anchorage mass, a cable, said cable including at least one cable strand, a bearing plate apposed to said cable, at least one rod opening in said bearing plate, at least one rod, said at least one rod gripped at least at one of its ends remote from said bearing plate, the other end of said at least one rod extending through at least one bearing plate opening, means to fasten said at least one extending rod held bearing upon said bearing plate, means bearing upon said bearing plate to hold said at least one said cable strand, tightening means including said bearing plate and said at least one rod to stress said cable anchor mass, means clear of said at least one rod held bearing upon said bearing plate to retain at least one cable strand, and means to tension said at least one cable strand against said anchorage mass''s stress.

2. The invention of claim 1 wherein said anchorage mass is bedrock.

15. The invention of claim 14 wherein said nut rests in a rounded washer.

16. The invention of claim 15 wherein said opening in said bearing plate for said cable strand holding means is flared outward to the face of said front bearing plate.

20. The invention of claim 19 wherein said nut rests in a rounded washer.

22. The invention of claim 17 wherein said socket is T shaped.

27. The invention of claim 26 further including at least one shim.

34. The invention of claim 33 further including at least one shim.