WO2004111363A1 - A coupler - Google Patents
A coupler Download PDFInfo
- Publication number
- WO2004111363A1 WO2004111363A1 PCT/AU2004/000780 AU2004000780W WO2004111363A1 WO 2004111363 A1 WO2004111363 A1 WO 2004111363A1 AU 2004000780 W AU2004000780 W AU 2004000780W WO 2004111363 A1 WO2004111363 A1 WO 2004111363A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- insert
- coupler
- shank
- bar
- reinforcing bar
- Prior art date
Links
- 230000003014 reinforcing effect Effects 0.000 claims abstract description 91
- 230000036316 preload Effects 0.000 claims abstract description 20
- 230000000712 assembly Effects 0.000 claims description 7
- 238000000429 assembly Methods 0.000 claims description 7
- 238000011068 loading method Methods 0.000 claims description 6
- 230000000295 complement effect Effects 0.000 claims description 4
- 230000007704 transition Effects 0.000 claims description 2
- 230000008878 coupling Effects 0.000 claims 1
- 238000010168 coupling process Methods 0.000 claims 1
- 238000005859 coupling reaction Methods 0.000 claims 1
- 239000004567 concrete Substances 0.000 description 18
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C5/00—Reinforcing elements, e.g. for concrete; Auxiliary elements therefor
- E04C5/16—Auxiliary parts for reinforcements, e.g. connectors, spacers, stirrups
- E04C5/162—Connectors or means for connecting parts for reinforcements
- E04C5/163—Connectors or means for connecting parts for reinforcements the reinforcements running in one single direction
- E04C5/165—Coaxial connection by means of sleeves
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/38—Connections for building structures in general
- E04B1/41—Connecting devices specially adapted for embedding in concrete or masonry
- E04B1/4114—Elements with sockets
- E04B1/4121—Elements with sockets with internal threads or non-adjustable captive nuts
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
- E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
- E04B1/38—Connections for building structures in general
- E04B1/41—Connecting devices specially adapted for embedding in concrete or masonry
- E04B2001/4192—Connecting devices specially adapted for embedding in concrete or masonry attached to concrete reinforcing elements, e.g. rods or wires
Definitions
- the present invention relates to a coupler for mechanically splicing together reinforcing bars.
- the present invention also relates to a coupler for mechanically connecting a reinforcing bar to a rigid object, such as an anchored steel plate, to which the coupler is welded or otherwise secured.
- reinforcing bars it is often important to be able to mechanically connect reinforcing bars to rigid objects, such as anchored steel plates, in the field so that the bars can develop a large part or even their full axial capacity in either tension or compression.
- Couplers may have a fine thread or a coarse thread.
- Coarse threaded couplers are used in situations where the ribs or deformations of hot or cold rolled reinforcing bars form the bar thread - invariably, ribs or deformations form coarse threads on bars .
- Longitudinal slip is more pronounced generally and therefore is more of an issue with coarse-threaded couplers than with fine-threaded couplers under service load conditions. Longitudinal slip up to 1 mm or more can occur in coarse threaded couplers . A common limit for fine threaded couplers is 0.1mm.
- US patent 6,328,499 in the name of Reding et al discloses a coupler that includes a coupler body in the form of an internally threaded sleeve that can receive the end sections of 2 externally threaded bars and a cotter or 3 part wedge assembly that can be inserted through openings in the coupler body and apply oppositely directed axial forces to the ends of the bars and pre-load the ends of the bars and thereby limit longitudinal slip between the bars and the coupler.
- the gross section of the coupler body must also be increased as a consequence of providing the openings.
- the bars must always be rotated / which is not always possible, e.g. with bars with cranked ends, i.e. the coupler can be used as a turnbuckle.
- Two openings are provided at 90 degrees to each other to improve access, but this is still not guaranteed on a building site, depending on the situation, e.g. when splicing closely-spaced bars in a column access is restricted to the outside of the column cage.
- An object of the present invention is to provide an alternative coupler to that disclosed in the Reding US patent that limits relative longitudinal slip between reinforcing bars (particularly coarse-threaded bars) and is not subject to at least some of the above-described disadvantages of the Reding coupler.
- a coupler for a reinforcing bar having an external thread including (a) an insert having an externally threaded shank and (b) a body having an internally threaded bore extending through the body, the body being adapted to receive the shank of the insert via one end of the bore and to receive an end section of the reinforcing bar via an opposite end of the bore, whereby in use relative rotation of the insert and the body moves the ends of the shank and the reinforcing bar within the body axially into contact and applies an axial force to the end of the reinforcing bar and thereby preloads the reinforcing bar.
- the pre-load applied to the reinforcing bar is applied via the insert, and the friction interface between the bar and the shank has a low polar second moment of area, with the result that the required tightening torques are moderate and can be applied with standard spanners.
- the present invention is based on the realisation that applying a direct axial force to the end of the reinforcing bar by means of the shank of the insert is an effective way of generating significant levels of pre-load on the bar and coupler threads that are necessary to minimise longitudinal slip of the reinforcing bar relative to the body when the bar is loaded under service conditions in hardened concrete.
- the applicant has shown that it is possible to generate significantly higher levels of preload to a reinforcing bar by applying a direct axial force to an end of a reinforcing bar located in a coupler than can be achieved with known pre-loading methods, such as by rotating a reinforcing bar into a coupler against a reaction surface located in the coupler or by turning a locknut to pull a reinforcing bar from a coupler end.
- the present invention avoids the disadvantage of known pre-loading methods, such as methods involving the use of locknuts, of inducing high torsional stresses in a reinforcing bar and thereby reducing the strength of the bar or causing torsional failure of the bar.
- One known option for avoiding this disadvantage is to put a bar in tension first by using a specifically-designed hydraulic jack to grip the bar on each side of a coupler, thereafter engaging locknuts with the coupler ends, and then releasing the force in the bar.
- this option of inducing large pre-loading is less practical than the present invention.
- the axial force i.e, the pre-loading force is at least equivalent to 200 MPa.
- the axial force is at least equivalent 300 MPa.
- the amounts of 200-300 MPa are a significant proportion of the maximum tensile stresses that the reinforcing bars are likely to experience in normal service conditions.
- the external thread of the shank of the insert may be a thread cut into the shank.
- Such threads are generally regarded as being "fine" threads.
- the fine thread has a pitch of 2 -3mm.
- the external thread of the reinforcing bar may be ribs or deformations on the bar. Such threads are generally regarded as being “coarse” threads. Typically, the coarse thread has a pitch of 10mm.
- the reinforcing bar has a coarse external thread and the shank of the insert has a relatively fine thread.
- the bore of the body has a complementary coarse thread in one section of the bore extending from one end of the body and a complementary relatively fine thread in another section of the bore extending from the other end of the body.
- the transition between the coarse and fine threaded sections forms a stop for axial movement of the reinforcing bar and the shank of the insert in the body.
- the external diameter of the shank of the insert is less than the internal diameter of the coarse-threaded section of the body so that the coarse- threaded section does not interfere with axial movement of the insert shank in situations in which the insert shank extends into this section of the body.
- the shank of the insert includes a formation that includes a series of angled faces that enable the insert to be gripped by a spanner.
- the coupler is suitable for use in two applications in particular. It is noted that these are not the only two applications of the coupler.
- the coupler mechanically connects reinforcing bars to fixed objects, such as anchored steel plates.
- the coupler mechanically splices together two reinforcing bars.
- the coupler includes two separate bodies, with each body having an internally threaded bore extending through the body, and the insert includes a central element and two externally threaded shanks extending in opposite directions from the central element, with each body being adapted to receive one of the shanks of the insert via one end of the bore and to receive an end section of one of the reinforcing bars via an opposite end of the bore, whereby relative rotation of the insert and the bodies moves the ends of each pair of the shanks and the reinforcing bars axially into contact and applies oppositely directed axial forces to the ends of the reinforcing bars and thereby pre-loads the reinforcing bars .
- each body includes a coarse thread in one section of the bore extending from one end of the body and a relatively fine thread in another section of the bore extending from the other end of the body.
- shanks of the insert have the same thread as the fine-threaded section of the bodies.
- the threads on each shank of the insert may be the same hand or opposite hands when the insert is viewed from a side of the insert.
- the insert can function as a turnbuckle.
- the insert With the bodies assembled onto the ends of coaxially aligned reinforcing bars, and the insert positioned so that each shank of the insert is engaged with one of the bar/body assemblies, rotation of the insert about its lengthwise extending axis pulls the bar/body assemblies toward each other without requiring rotation of the bars about their lengthwise extending axes and facilitates applying a required pre-load to each bar.
- the central element of the insert is formed as a nut that has angled faces so that the nut can be gripped by a spanner.
- the reinforcing bars have a diameter of at least 10 mm.
- the yield stress of the reinforcing bars is at least 400 MPa.
- the yield stress of the reinforcing bars is at least 500 MPa.
- Figure 1 is a diagrammatic cross-section of one embodiment of a coupler in accordance with the present invention for mechanically splicing together two reinforcing bars in end-to-end relationship;
- Figure 2 is a free body diagram that illustrates the force transfer on one side of the coupler shown in Figure 1;
- Figures 3 to 5 are diagrammatic cross-sections of other embodiments of the coupler in accordance with the present invention for mechanically connecting a reinforcing bar to a rigid object.
- the coupler shown in Figure 1 is suitable for mechanically connecting two externally threaded reinforcing bars 17.
- the coupler includes a body in the form of two sleeves 3 having internally-threaded bores 5 and an insert 9 having a central nut 11 and two axially-aligned externally threaded shanks 13.
- Each sleeve 3 of the body has a first threaded section extending from one end of the bore that has the same thread as the thread of the reinforcing bars 17 and a second threaded section extending from the other end of the bore that has the same thread as the thread of the shanks 13 of the insert 9.
- the reinforcing bars 17 have a thread that is relatively coarse compared to that of the shanks 13 of the insert 9.
- the central nut 11 of the insert 9 has a series of angled faces that enable the nut 11 to be gripped by a spanner .
- two reinforcing bars 17 are mechanically spliced together as shown in Figure 1 by firstly rotating each bar 17 into the bore 5 of one of the sleeves 3 to the maximum extent possible until the end of the bar reaches the end of the coarse internal thread of the sleeve 3. Thereafter, one of the shanks 13 of the insert 9 is rotated into one of the bar/sleeve assemblies until the end of the shank contacts the end of the bar 17 in the assembly and is tightened against the end of the bar 17 until the required pre-load is applied.
- the required tightening of the shank 13 against the end of the bar 17 can be achieved without difficulty by means of standard spanners.
- the other shank 13 of the insert is engaged with the other bar/sleeve assembly so that the required pre-load is applied to the bar 17 of that assembly.
- the pre-load of the bars 17 reduces the amount of longitudinal slip between the bars 17 and the open ends of the coupler .
- the amount of longitudinal slip between the bars 17 and the coupler is an inverse relationship with the amount of pre-load applied to the bar 17.
- the stress is applied to a much greater portion of the ends of the reinforcing bars 17, particularly in situations in which the ends of the bars are cut square.
- the bars can be cut in a factory or on site.
- the insert 9 can rotate relative to the end of a bar and achieve the necessary bearing pressure without requiring a complicated mechanism like the cotter of the Reding coupler.
- the fine-threaded insert 7 applies a compressive force to the end of the reinforcing bar 17 to deform the coarse threads of the bar and the coupler.
- An equal and opposite tensile force develops in the coupler body.
- the diameter of the insert shank is less than that of the bar, but nevertheless the average contact stress on the end of the bar needed to overcome the slip problem is much less than that using the cotter of the Reding coupler.
- the objective is to connect a reinforcing bar 17b to a reinforcing bar 17a that is embedded in concrete 25.
- Figure 3 illustrates a pair of parallel reinforcing bars 17a that was embedded in the concrete 25 in a "previous" pour.
- a coupler sleeve 3 of the coupler shown in Figure 1 (identified by the numeral 3a in Figure 3) is engaged with the end of the lower bar 17a and is also embedded in the concrete 25.
- the coupler sleeve 3a is positioned in the concrete 25 so that the bore of the sleeve 3a can be accessed from the exposed face 91 of the concrete 25 at that time .
- one of the shanks 13 of the insert 9 is wound into the bore of the sleeve 3a and the insert is tightened to provide a required pre-load to the bar 17a.
- the action of tightening the insert 9 brings the end of the shank 13 into contact with the end of the bar 17a within the coupler sleeve 3a, and further tightening of the insert thrusts the shank 13 against the end of the bar 17a and has the result of moving the sleeve 3a within the concrete 25 towards the insert 9. Consequently, it is important that the coupler sleeve 3a be formed to minimise interference to the necessary longitudinal movement of the sleeve 3a.
- the insert can act as a turnbuckle and the bar/sleeve assembly that includes the reinforcing bar 17b can be engaged with the insert 9 by rotating the insert 9 rather that the bar/sleeve assembly.
- the objective is to secure a reinforcing bar 17 to a precast panel 29.
- An anchor 31 for the reinforcing bar 17 is embedded in the precast panel 29.
- the anchor 31 has an internally fine threaded bore.
- the insert 9 and one of the coupler sleeves 3 of the coupler shown in Figure 1 connect the reinforcing bar 17 to the anchor 31.
- one shank 13 of the insert 9 is wound into the anchor 31. Thereafter, the coupler sleeve 3 is wound onto the reinforcing bar 17 and the bar/sleeve assembly is wound onto the other shank 13 of the insert 9 and tightened to provide a required pre-load.
- the insert can act as a turnbuckle and the bar/sleeve assembly that includes the reinforcing bar 17 can be engaged with the insert 9 by rotating the insert 9 rather that the bar/sleeve assembly.
- the objective is to anchor a series of reinforcing bars 17b that form part of vertical column starters 51 to a reinforced concrete base 53.
- Figure 5 illustrates three parallel vertically extending reinforcing bars 17a embedded in the concrete base 53.
- the coupler sleeves 3a are positioned in the concrete base 53 so that the bores of the sleeves 3 can be accessed from the exposed top face 55 of the concrete base 53.
- the reinforcing bars 17b are connected to the bars 17a by means of the coupler shown in Figure 1 - and as illustrated on the left hand side of Figure 5.
- the inserts can act as turnbuckle and the bar/sleeve assemblies that include the reinforcing bars 17b can be engaged with the inserts 9 by rotating the inserts 9 rather that the bar/sleeve assemblies.
- the present invention is not limited to couplers that receive one or two reinforcing bars as shown in the Figures and also extends to couplers that can receive in excess of two bars. In such couplers the bars need not be in the same plane.
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Reinforcement Elements For Buildings (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NZ544610A NZ544610A (en) | 2003-06-13 | 2004-06-11 | A turnbuckle coupling for joining and pre-stressing reinforcing rods |
AU2004247749A AU2004247749B2 (en) | 2003-06-13 | 2004-06-11 | A coupler |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2003902986 | 2003-06-13 | ||
AU2003902986A AU2003902986A0 (en) | 2003-06-13 | 2003-06-13 | A coupler |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2004111363A1 true WO2004111363A1 (en) | 2004-12-23 |
Family
ID=31954027
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/AU2004/000780 WO2004111363A1 (en) | 2003-06-13 | 2004-06-11 | A coupler |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU2003902986A0 (en) |
NZ (1) | NZ544610A (en) |
WO (1) | WO2004111363A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2503228A (en) * | 2012-06-19 | 2013-12-25 | Laing O Rourke Plc | Pre-cast column assembly with reinforcement and connection parts |
CN106545168A (en) * | 2015-09-17 | 2017-03-29 | 中国二十冶集团有限公司 | Infilled wall tie bar connection construction method |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN117905108B (en) * | 2024-03-19 | 2024-05-28 | 福建一建集团有限公司 | Construction method for building engineering reverse construction method of civil air defense in heavy-layer water-bearing sand layer |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2427169A1 (en) * | 1973-07-05 | 1975-01-23 | Theodor Dipl Ing Dr Tech Titze | Reinforced concrete joint element connection - comprising common connecting organ with spacer member transmitting pressure between interfacing surfaces |
GB1534886A (en) * | 1975-10-15 | 1978-12-06 | Ccl Systems Ltd | Joining bodies of concrete |
JPH08284320A (en) * | 1995-04-11 | 1996-10-29 | D B S:Kk | Device and method for connecting bar |
DE20111793U1 (en) * | 2001-07-19 | 2001-09-20 | Schoeck Entwicklungsgmbh | Socket connection for concrete bars |
US6328499B1 (en) * | 1999-03-17 | 2001-12-11 | Ares S.A. | Screwed connection for threaded rods |
-
2003
- 2003-06-13 AU AU2003902986A patent/AU2003902986A0/en not_active Abandoned
-
2004
- 2004-06-11 WO PCT/AU2004/000780 patent/WO2004111363A1/en active Application Filing
- 2004-06-11 NZ NZ544610A patent/NZ544610A/en unknown
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2427169A1 (en) * | 1973-07-05 | 1975-01-23 | Theodor Dipl Ing Dr Tech Titze | Reinforced concrete joint element connection - comprising common connecting organ with spacer member transmitting pressure between interfacing surfaces |
GB1534886A (en) * | 1975-10-15 | 1978-12-06 | Ccl Systems Ltd | Joining bodies of concrete |
JPH08284320A (en) * | 1995-04-11 | 1996-10-29 | D B S:Kk | Device and method for connecting bar |
US6328499B1 (en) * | 1999-03-17 | 2001-12-11 | Ares S.A. | Screwed connection for threaded rods |
DE20111793U1 (en) * | 2001-07-19 | 2001-09-20 | Schoeck Entwicklungsgmbh | Socket connection for concrete bars |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2503228A (en) * | 2012-06-19 | 2013-12-25 | Laing O Rourke Plc | Pre-cast column assembly with reinforcement and connection parts |
CN106545168A (en) * | 2015-09-17 | 2017-03-29 | 中国二十冶集团有限公司 | Infilled wall tie bar connection construction method |
Also Published As
Publication number | Publication date |
---|---|
AU2003902986A0 (en) | 2003-06-26 |
NZ544610A (en) | 2007-11-30 |
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