CA1129689A - Ground anchors - Google Patents
Ground anchorsInfo
- Publication number
- CA1129689A CA1129689A CA330,117A CA330117A CA1129689A CA 1129689 A CA1129689 A CA 1129689A CA 330117 A CA330117 A CA 330117A CA 1129689 A CA1129689 A CA 1129689A
- Authority
- CA
- Canada
- Prior art keywords
- sleeve
- anchor
- cap
- self
- setting composition
- 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
Links
Landscapes
- Piles And Underground Anchors (AREA)
Abstract
Fosroc International Limited CBP 102 ABSTRACT
A method of making on site, a ground anchor comprising an anchor element (9) having a corrosion proof sleeve (1)secured to an end portion of the element, comprises locating a number of lengths of the slee-ve (1) about the end portion of the element (9), applying a cap (11) to the end of the sleeve, and supplying a self-setting composition via the cap into an annular clearance (15) between the sleeve (1) and the element (9). The cap (11) may be left in place to seal the end of the anchor and to protect the anchor during insertion into a borehole. The sleeve (1) preferably com-prises an outer layer of plastics, an intermediate layer of set filler and an inner layer of metal. The invention includes the sleeved anchor element and the sleeve lengths themselves.
A method of making on site, a ground anchor comprising an anchor element (9) having a corrosion proof sleeve (1)secured to an end portion of the element, comprises locating a number of lengths of the slee-ve (1) about the end portion of the element (9), applying a cap (11) to the end of the sleeve, and supplying a self-setting composition via the cap into an annular clearance (15) between the sleeve (1) and the element (9). The cap (11) may be left in place to seal the end of the anchor and to protect the anchor during insertion into a borehole. The sleeve (1) preferably com-prises an outer layer of plastics, an intermediate layer of set filler and an inner layer of metal. The invention includes the sleeved anchor element and the sleeve lengths themselves.
Description
Ground anchors This invention concerns ground anchors for use in the civil engineering, construction and mining industries for example.
There is a requirement for ground anchors to have at least a double corrosion protection about the central anchor element, such ~as that p~ovided by a waterproof sleeve~which is grouted on to t:he element. Such anchors are known, but the sleeves are applied to the anchor element in a factory and each anchor must be purpose-lQ built. This makes it expensive to manufacture and - transport a small number of anchors for a specific application, and there is often a long delay before the anchors can be delivered to the site of use. There is therefore a need for a simple and cheap way of corro-sion proofing an anchor element on site to specificrequirements, and this invention fulfills that need~
` According to one aspect of the invention there is provided a method of at least double corrosion proofing an anchor element on site, comprising (i) locating a plurality of lengths of corrosion proof sleeve in end-to-end relation about an end portion of the anchor element to cover the length of the element to be corro-sion proofed, said sleeve comprising three layers wherein the outer layers are corrosion-proof and at least one is . . .
: ~ "
: ~ :
plastic, and the intermediate layer is of a set filler, (ii) applying a cap to the sleeve at the end o~ the anchor element, the cap having an inlet for self-setting compo-sition, and (iii) supplying a self-setting composition through the inlet, via the cap, into an annular clearance between the element and the sleeve there to set to secure the sleeve to the element.
According to another aspect of the invention there is provided an anchor, comprising an anchor element, a 10 plurality of sleeve lengths being located in end-to-end relation about an end portion of the element, the sleeve lengths being secured to the element by means of a self-setting c~omposition located between the element and the sleeve, the sleeve comprising an outer layer of plastics 15 having external castellations, an intermediate layer of set filler and an inner layer of metal being internally threaded, and a cap being secured to an end of the anchor by means of the self-setting composition.
Preferably the cap is secured to the anchor element by 20 means of the self-setting composition to seal the end of the anchor against ingress of moisture and to protect the leading end of the anchor during insertion into a borehole.
he sleeve lengths will usually be connected together such that the sleeve is sealed against escape of self-25 setting composition during introduction of the compositioninto the sleeve.
Preferably the sleeved anchor element is upwardly inclined away from the cap for best escape of air whilst the self-setting composition is supplied into the sleeve.
The inlet is preferably located in the side of the cap.
When the anchor is upwardly inclined for introduction of self-setting composition, the inlet is less liable to damage in this location, and the inlet is less likely ~` to become blocked by dirt.
The sleeve preferably has at least two corrosion~proof layers. It is especially preferred for the sleeve to ,, ~ 2a -comprise three layers, the intermediate layer being of set filler such as a resinous or a cementitious grout and at least one of the other two layers being of plastics. Most preferably the sleeve comprises an outer layer of plastics, an intermediate layer of set filler and an inner layer of metal. The metal inner layer serves to strengthen the sleeve for handling purposes.
The anchor element may be a bar such as Macalloy*
or Dividag* bar having either a plain or a ribbed pro-file. Plain bars may be used with threaded nuts andplain washers, the nuts being screw-threaded on to a co-operatively threaded end portion of the bar.
* Trade Mark .d>~
- ~ - GBP 102 Ribbed bars do not require the use of a nut and washer, but rely instead upon the ribs to transfer load from the tendon to the sleeve.
The method is particularly useful for corrosion proof-ing strand tendons. Known factor~J methods require "nodin~" of ~5 each strand to transfer the stress from the strands to the sleeve, This noding involves removal of a polypropylene coating from the length of the tendon to be corrosion proofed, followed by untwlsting of the strands and thorough~cleaning off of any grease from the strands. A node is then applied to each strand whereupon the strands are re-twisted and secured inside the sleeve. rne nodes serve to lock the strands to the sleeve.
When the method of the invention is used to corrosion proof a strand tendon on site, the plastics sheathing is stripped off the tendon and the tendon surface is wiped free OL srease /~5 without untwisting the strands. A metal ferrule is then compressed onto the end of the tendon for best transfer of tendon load to ~he sleeve. me sleeve ls then secured to the end portion of the tendon by the method of the invention~
The sleeve should have longitudinally spaoed apart 0~ external circumlerential ribs and should be internally threaded to respectively provide a good ke~ between the sleeve and the grout used to secure the element in the hole,and between ~he sleeve and the sel~ setting composition which is used to secure the sleeve to -the anchor element.
~5 The invention includes a ground anchor made by the method, ard further includes the sleeve lengths themselves as new items of commerce, The invention is described below by way of example with - reference to the accompanying diagrammatic drawings in which Figure 1 is a side view, partly ln section, of a length of sleeve for use in the method~
Figure 2 is a sectional view showing the sleeve being secured to an anchor element by the method of the invention, ~nd _ h _ CBP 102 Figure ~ is a sectional view of an alternative method of securing together two sleeve lengths.
The sleeve 1 of ~lgure 1 comprises an outer tube 2 of p~astics, the tube hav~ng spaced-apart castellations ~, an inner steel tube 4 having a thread 5, and an intermedia~e layer of set polyester resin 6. Both ends of the sleeve 1J only one end being shown for convenience in Figure 1, have two diametricall~J opposite recesses 7. Towards each end of the sleeve, an 0-ring 8 is located about the tube between the cas~ellations ~. -~O In use, a ribbed steel bar 9, Figure 2, to be corrosion proofed ~or use as a ground anchor, is mounted on a trestleJ not shown, at a construction site. A suitable number o~ sleeve lengths 1 are ~itted over one end o~ the rod 9 in end-to-end relation. For convenience only two sleeve lengths are shotm in Figure 2. A
~5 connecting tube 10 is fitted over the adjacent 0-rings 8 o~ adjacent sleeve lengths. An end cap 11 comprising a mouth oortion 12 and a s~de inlet 13, is fittad over the end of the sleeve. The clearance between the mouth 12 of the end cap 11 and the sleeve 1 is sealed by the adJacent 0-ring 8.
: a ~ A polyester resin grout 14 is then pumped through the inlet 13 of the cap 11 into the annular clearance 15 between the sleeve and the rod. The anchoris upwardly inclined a~y from the end cap for best escape of air during introduction of the grout.
Tne grout is forced into the clearance between adjacent ends of ~1 S the sleeve lengths there to provide a molsture-proof seal. The recesses 7 facilitate passage of the grout between the sleeve ends and also act as Xeys more firmly to secure the sleeve lengths to-gether ~ means of the grout within the recesses.
Af-ter sufficient time to allow the polyester grout to harden~ the inlet 1~ is sawn off and the anohor located in a hole in a substrate in known manner. The cap 11 serves as a guide for the anchor and protects the leading end of the anchor during inser-tion into a hole. The grout ~ thin the end cap 11 seals the end of '' ' ~
~2~
the anchor against penetration of moisture.
A strand tendon may be used in place of the rod 9.
In this case, the tendon is prepared by removing the protective sheath along the length of the tendon to be corrosion proofed.
The bared tendon is then thoro~hly degreased and a ferrule is compressed on to the end of the tendon. The tendon is then sleeved as described, the ferrule being located within the cap 11.
Figure 3 shoNs an alternative way of joi~lng together adjacent sleeve lengths. The ex~ernal ~lastics layer 2 of one sleeve length la has a female extension 16, and the same layer of the adjacent sleeve length lb has a male extension 17. The extensions 16, 17 are screw-threaded one into the other.
The method o~ the invention allows corrosion-proof anchors to be made quickly and cheaply on site to meet individual requirements. The sleeve is capable of transferring the maximum load of the anchor element to the borehole grout, provided a sufficient length of sleeve is used. The minimum length of sleeve for full load trans~er ranges ~rom 4 m ~or a 110 mm external dia-meter sleeve, to 1.5 m for a 65 mm external diameter slee~e, .
.
There is a requirement for ground anchors to have at least a double corrosion protection about the central anchor element, such ~as that p~ovided by a waterproof sleeve~which is grouted on to t:he element. Such anchors are known, but the sleeves are applied to the anchor element in a factory and each anchor must be purpose-lQ built. This makes it expensive to manufacture and - transport a small number of anchors for a specific application, and there is often a long delay before the anchors can be delivered to the site of use. There is therefore a need for a simple and cheap way of corro-sion proofing an anchor element on site to specificrequirements, and this invention fulfills that need~
` According to one aspect of the invention there is provided a method of at least double corrosion proofing an anchor element on site, comprising (i) locating a plurality of lengths of corrosion proof sleeve in end-to-end relation about an end portion of the anchor element to cover the length of the element to be corro-sion proofed, said sleeve comprising three layers wherein the outer layers are corrosion-proof and at least one is . . .
: ~ "
: ~ :
plastic, and the intermediate layer is of a set filler, (ii) applying a cap to the sleeve at the end o~ the anchor element, the cap having an inlet for self-setting compo-sition, and (iii) supplying a self-setting composition through the inlet, via the cap, into an annular clearance between the element and the sleeve there to set to secure the sleeve to the element.
According to another aspect of the invention there is provided an anchor, comprising an anchor element, a 10 plurality of sleeve lengths being located in end-to-end relation about an end portion of the element, the sleeve lengths being secured to the element by means of a self-setting c~omposition located between the element and the sleeve, the sleeve comprising an outer layer of plastics 15 having external castellations, an intermediate layer of set filler and an inner layer of metal being internally threaded, and a cap being secured to an end of the anchor by means of the self-setting composition.
Preferably the cap is secured to the anchor element by 20 means of the self-setting composition to seal the end of the anchor against ingress of moisture and to protect the leading end of the anchor during insertion into a borehole.
he sleeve lengths will usually be connected together such that the sleeve is sealed against escape of self-25 setting composition during introduction of the compositioninto the sleeve.
Preferably the sleeved anchor element is upwardly inclined away from the cap for best escape of air whilst the self-setting composition is supplied into the sleeve.
The inlet is preferably located in the side of the cap.
When the anchor is upwardly inclined for introduction of self-setting composition, the inlet is less liable to damage in this location, and the inlet is less likely ~` to become blocked by dirt.
The sleeve preferably has at least two corrosion~proof layers. It is especially preferred for the sleeve to ,, ~ 2a -comprise three layers, the intermediate layer being of set filler such as a resinous or a cementitious grout and at least one of the other two layers being of plastics. Most preferably the sleeve comprises an outer layer of plastics, an intermediate layer of set filler and an inner layer of metal. The metal inner layer serves to strengthen the sleeve for handling purposes.
The anchor element may be a bar such as Macalloy*
or Dividag* bar having either a plain or a ribbed pro-file. Plain bars may be used with threaded nuts andplain washers, the nuts being screw-threaded on to a co-operatively threaded end portion of the bar.
* Trade Mark .d>~
- ~ - GBP 102 Ribbed bars do not require the use of a nut and washer, but rely instead upon the ribs to transfer load from the tendon to the sleeve.
The method is particularly useful for corrosion proof-ing strand tendons. Known factor~J methods require "nodin~" of ~5 each strand to transfer the stress from the strands to the sleeve, This noding involves removal of a polypropylene coating from the length of the tendon to be corrosion proofed, followed by untwlsting of the strands and thorough~cleaning off of any grease from the strands. A node is then applied to each strand whereupon the strands are re-twisted and secured inside the sleeve. rne nodes serve to lock the strands to the sleeve.
When the method of the invention is used to corrosion proof a strand tendon on site, the plastics sheathing is stripped off the tendon and the tendon surface is wiped free OL srease /~5 without untwisting the strands. A metal ferrule is then compressed onto the end of the tendon for best transfer of tendon load to ~he sleeve. me sleeve ls then secured to the end portion of the tendon by the method of the invention~
The sleeve should have longitudinally spaoed apart 0~ external circumlerential ribs and should be internally threaded to respectively provide a good ke~ between the sleeve and the grout used to secure the element in the hole,and between ~he sleeve and the sel~ setting composition which is used to secure the sleeve to -the anchor element.
~5 The invention includes a ground anchor made by the method, ard further includes the sleeve lengths themselves as new items of commerce, The invention is described below by way of example with - reference to the accompanying diagrammatic drawings in which Figure 1 is a side view, partly ln section, of a length of sleeve for use in the method~
Figure 2 is a sectional view showing the sleeve being secured to an anchor element by the method of the invention, ~nd _ h _ CBP 102 Figure ~ is a sectional view of an alternative method of securing together two sleeve lengths.
The sleeve 1 of ~lgure 1 comprises an outer tube 2 of p~astics, the tube hav~ng spaced-apart castellations ~, an inner steel tube 4 having a thread 5, and an intermedia~e layer of set polyester resin 6. Both ends of the sleeve 1J only one end being shown for convenience in Figure 1, have two diametricall~J opposite recesses 7. Towards each end of the sleeve, an 0-ring 8 is located about the tube between the cas~ellations ~. -~O In use, a ribbed steel bar 9, Figure 2, to be corrosion proofed ~or use as a ground anchor, is mounted on a trestleJ not shown, at a construction site. A suitable number o~ sleeve lengths 1 are ~itted over one end o~ the rod 9 in end-to-end relation. For convenience only two sleeve lengths are shotm in Figure 2. A
~5 connecting tube 10 is fitted over the adjacent 0-rings 8 o~ adjacent sleeve lengths. An end cap 11 comprising a mouth oortion 12 and a s~de inlet 13, is fittad over the end of the sleeve. The clearance between the mouth 12 of the end cap 11 and the sleeve 1 is sealed by the adJacent 0-ring 8.
: a ~ A polyester resin grout 14 is then pumped through the inlet 13 of the cap 11 into the annular clearance 15 between the sleeve and the rod. The anchoris upwardly inclined a~y from the end cap for best escape of air during introduction of the grout.
Tne grout is forced into the clearance between adjacent ends of ~1 S the sleeve lengths there to provide a molsture-proof seal. The recesses 7 facilitate passage of the grout between the sleeve ends and also act as Xeys more firmly to secure the sleeve lengths to-gether ~ means of the grout within the recesses.
Af-ter sufficient time to allow the polyester grout to harden~ the inlet 1~ is sawn off and the anohor located in a hole in a substrate in known manner. The cap 11 serves as a guide for the anchor and protects the leading end of the anchor during inser-tion into a hole. The grout ~ thin the end cap 11 seals the end of '' ' ~
~2~
the anchor against penetration of moisture.
A strand tendon may be used in place of the rod 9.
In this case, the tendon is prepared by removing the protective sheath along the length of the tendon to be corrosion proofed.
The bared tendon is then thoro~hly degreased and a ferrule is compressed on to the end of the tendon. The tendon is then sleeved as described, the ferrule being located within the cap 11.
Figure 3 shoNs an alternative way of joi~lng together adjacent sleeve lengths. The ex~ernal ~lastics layer 2 of one sleeve length la has a female extension 16, and the same layer of the adjacent sleeve length lb has a male extension 17. The extensions 16, 17 are screw-threaded one into the other.
The method o~ the invention allows corrosion-proof anchors to be made quickly and cheaply on site to meet individual requirements. The sleeve is capable of transferring the maximum load of the anchor element to the borehole grout, provided a sufficient length of sleeve is used. The minimum length of sleeve for full load trans~er ranges ~rom 4 m ~or a 110 mm external dia-meter sleeve, to 1.5 m for a 65 mm external diameter slee~e, .
.
Claims (8)
1. A method of at least double corrosion proofing an anchor element on site, comprising (i) locating a plurality of lengths of corrosion proof sleeve in end-to-end relation about an end portion of the anchor element to cover the length of the element to be corrosion proofed, said sleeve comprising three layers wherein the outer layers are corrosion-proof and at least one is plastic, and the intermediate layer is of a set filler, (ii) applying a cap to the sleeve at the end of the anchor element, the cap having an inlet for self-setting composition, and (iii) supplying a self-setting composition through the inlet, via the cap, into an annular clearance between the element and the sleeve there to set to secure the sleeve to the element.
2. A method according to Claim 1, in which the cap is secured to the anchor element by means of the self-setting composition.
3. A method according to Claim 1, in which the sleeved anchor element is upwardly inclined away from the cap whilst the self-setting composition is supplied into the sleeve.
4. A method according to any one of Claims 1 to 3, in which the inlet is located in the side of the cap.
5. A method according to any one of Claims 1 to 3, in which the sleeve comprises an outer layer of plastics, an intermediate layer of set filler and an inner layer of metal.
6. A method according to Claim 1, Claim 2 or Claim 3, in which the anchor element is a bar having a plain or a ribbed profile.
7. A method according to Claim 1, Claim 2 or Claim 3, in which the anchor element is a strand tendon.
8. An anchor, comprising an anchor element, a plurality of sleeve lengths being located in end-to-end relation about an end portion of the element, the sleeve lengths being secured to the element by means of a self-setting composition located between the element and the sleeve, the sleeve comprising an outer layer of plastics having external castellations, an intermediate layer of set filler and an inner layer of metal being internally threaded, and a cap being secured to an end of the anchor by means of the self-setting composition.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA330,117A CA1129689A (en) | 1979-06-19 | 1979-06-19 | Ground anchors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA330,117A CA1129689A (en) | 1979-06-19 | 1979-06-19 | Ground anchors |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1129689A true CA1129689A (en) | 1982-08-17 |
Family
ID=4114490
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA330,117A Expired CA1129689A (en) | 1979-06-19 | 1979-06-19 | Ground anchors |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1129689A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014094134A1 (en) * | 2012-12-21 | 2014-06-26 | Laurentian University Of Sudbury | Mine support assembly |
-
1979
- 1979-06-19 CA CA330,117A patent/CA1129689A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014094134A1 (en) * | 2012-12-21 | 2014-06-26 | Laurentian University Of Sudbury | Mine support assembly |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |