NL2022034A

NL2022034A - A metal construction tie

Info

Publication number: NL2022034A
Application number: NL2022034A
Authority: NL
Inventors: De Heus Marinus
Original assignee: Jetmix B V
Priority date: 2018-11-20
Filing date: 2018-11-20
Publication date: 2020-05-26
Also published as: NL2022034B1

Abstract

Metal ties are used widely in construction, building and civil engineering projects because of their high tensile strength and load-bearing properties. They are typically made of a steel, and may have a lifetime of several years or even several decades. For practical reasons, metal ties generally comprise one or more metal members of fixed lengths, for example, 1 meter to 12 meters coupled rigidly together. However, providing adequate corrosion resistance is more complicated with ties comprising members and couplings, as all components of the tie must be protected. A metal construction tie is provided comprising: longitudinal metal members having a first end comprising an outer screw-thread, couplings comprising an inner bore with an inner screw-thread, configured and arranged to rigidly attach to the first end of the members by insertion and rotation, a coupling corrosion barrier, encapsulating at least a portion of the couplings, a member corrosion barrier, encapsulating at least a portion of the members proximate the first end, the coupling and member corrosion barriers being configured and arranged to engage after insertion of the first end such that the ingress of a fluid into the inner bore of the coupling is resisted; wherein both the coupling and member corrosion barriers comprise an elastomeric layer. By providing corrosion barriers comprising an elastomeric layer on at least one longitudinal member and a coupling that engage, the resistance to the ingress of a fluid is greatly improved. This increases the resistance to corrosion of the metal construction tie using relatively expensive materials.

Description

A METAL CONSTRUCTION TIE

FIELD

The present disclosure relates to a metal construction tie. In particular, it relates to a metal construction tie comprising an outer screw thread.

BACKGROUND

Metal ties are used widely in construction, building and civil engineering projects because of their high tensile strength and load-bearing properties. They are typically made of a steel, and may have a lifetime of several years or even several decades. They are often installed into a medium, such as soil, sand, clay, ground, rock or concrete, and may be used to secure or reinforce a retaining structure or wall. In general, they may be used in many applications requiring high tensile strength and/or load bearing, such as basements, parking garages, railway embankment tunnels, and masts. A disadvantage to metal ties is their susceptibility to corrosion, particularly in the hostile environments where they are frequently installed. For example, they may come into contact with water, salt water, groundwater, electrical stray currents and chemicals which may accelerate corrosion, increasing the chance of failure and possibly reducing the lifetime. Metals and alloys with improved corrosion resistance may be used, such as a stainless-steel, plastic or titanium, but they usually increase the cost of the tie and may not provide the desired mechanical properties.

To function for extended periods of time, one or more forms of corrosion protection are required. These include, for example: metal treatments, such as galvanization or applying a coating of a different metal, such as aluminum to the surface of the metal; sheaths and sleeves, fitted tightly over the surface of the tie; grout, introduced into the installation medium, and surrounding the tie; and tubing, having larger diameter than the tie, and being introduced into the installation medium surrounding the tie. Additionally or alternatively, ties thicker than structurally required may be used to compensate for material loss due to corrosion. In practice, combinations of measures are used to optimize the corrosion protection. However, this may significantly increase the cost of each tie and may also require longer to be installed in the medium.

Tie lengths of up to 30 meters are known but are difficult to transport and to install. For practical reasons, metal ties generally comprise one or more metal members of fixed lengths, for example, 1 meter to 12 meters coupled rigidly together. However, providing adequate corrosion resistance is more complicated with ties comprising members and couplings, as all components of the tie must be protected.

It is an object of the invention to provide an improved metal tie comprising one or more metal members and at least one coupling, having a high degree of corrosion protection using relatively inexpensive materials and treatments.

GENERAL STATEMENTS

According to a first aspect of the present disclosure, there is provided a metal construction tie comprising: one or more longitudinal metal members having a first end comprising an outer screw-thread; one or more couplings comprising an inner bore with an inner screw-thread, configured and arranged to rigidly attach to the first end of the one or more members by insertion and rotation of the first end into the inner bore; a coupling corrosion barrier, encapsulating at least a portion of the one or more couplings; a member corrosion barrier, encapsulating at least a portion of the one or more members proximate the first end; the coupling and member corrosion barriers being configured and arranged to engage after insertion of the first end such that the ingress of a fluid into the inner bore of the coupling is resisted; wherein both the coupling and member corrosion barriers comprise an elastomeric layer.

By providing corrosion barriers comprising an elastomeric layer on at least one longitudinal member and a coupling that engage, the resistance to the ingress of a fluid is greatly improved. This increases the resistance to corrosion of the metal construction tie using relatively inexpensive materials.

According to a further aspect of the current disclosure, there is provided a metal construction tie further comprising: a second longitudinal member having a first end comprising an outer screw-thread; a further member corrosion barrier, encapsulating at least a portion of the second member proximate the first end, comprising an elastomeric layer; wherein: the coupling is further configured and arranged to rigidly attach to the first end of the second member by insertion and rotation of the first end into the inner bore; the coupling and further member corrosion barriers being configured and arranged to engage after insertion of the first end of the second member such that the ingress of a fluid into the inner bore of the coupling is further resisted.

Almost any length of construction tie may be provided by using more than one longitudinal member. Between each pair of longitudinal member, a coupling is provided, configured and arranged to rigidly connect the components of the metal construction tie.

According to another aspect of the current disclosure, there is provided a metal construction tie wherein the elastomeric layer comprises polyurea and/or polyurethane.

Polyurea and/or polyurethane are relatively inexpensive and provide a good protection against corrosion when properly configured, and applied correctly to one or more couplings and one or more longitudinal members in the form of engageable corrosion barriers.

According to yet another aspect of the current disclosure, there is provided a metal construction tie, wherein the coupling further comprises a recess at the entrance to the inner bore, extending substantially over the whole circumference of the inner bore, whereby the coupling corrosion barrier forms a sealing feature for engaging with a member corrosion barrier.

By providing one or more additional sealing features, the risk of fluid ingress into the inner bore of a coupling is reduced.

According to another aspect of the current disclosure, there is provided a metal constaiction tie further comprising: a drill or drill head, comprising the one or more couplings.

By providing a drill head, the anchor may be configured to drill a hole for itself - that is, as a self-drilling anchor.

According to a still further aspect of the current disclosure, there is provided a metal construction tie wherein at least one longitudinal member has an inner bore, configured and arranged for the transport of fluids in longitudinal direction; and the inner bore of at least one coupling is further configured and arranged to provide a fluid communication channel between the inner bore of the at least one longitudinal member and a further member.

By providing an inner bore, fluids may be transported through the construction tie to the tip of the tie. Fluids, such as grout, resin or adhesive may be used to help secure the anchor in the ground, or in another medium.

According to another aspect of the current disclosure, there is provided a metal construction tie wherein the one or more couplings are integrated with one or more longitudinal members.

It may be advantageous to rigidly attach the couplings to at least one longitudinal member before installation - this may reduce the risk of fluid ingress as this eliminates one of the actions that needs to be done during installation which may damage the corrosion barrier.

According to still a further aspect of the current disclosure, a construction tie is provided, wherein the inner bore of the one or more coupling comprises an inner stop, configured and arranged to limit the insertion of a longitudinal member.

Elastomeric coatings are very sensitive, requiring correct positioning and avoidance of excessive force. It is therefore advantageous to control to a higher degree of accuracy the degree of insertion of the longitudinal members into the couplings.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of some embodiments of the present invention, and the manner in which the same are accomplished, will become more readily apparent upon consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings, which illustrate preferred and exemplary embodiments and which are not necessarily drawn to scale, wherein:

FIG. 1A and FIG. IB depict a longitudinal cross-section through conventional metal construction ties;

FIG. 2A and FIG. 2B depict longitudinal cross-sections through improved metal construction ties;

FIG. 3 A to 3G depict seven of how the corrosion barriers depicted in FIG. 2A and 2B may be configured to engage with each other;

FIG. 4A and FIG. 4B depict longitudinal cross-sections through the drill head end of two examples of improved drilling anchors;

FIG. 5 illustrates the use of an improved metal construction tie as a grout tie-back; and

FIG. 6 depicts a longitudinal cross-section through a conventional drilling anchor.

DETAILED DESCRIPTION

In the following detailed description, numerous non-limiting specific details are given to assist in understanding this disclosure.

FIG. 1A and FIG. IB depict a longitudinal cross-section through conventional metal construction ties 700, 701, comprising:

- a longitudinal member 720, 721, comprising a metal and/or alloy. The length is typically many times greater than the diameter. The diameter is typically in the range of a few millimeters to a several tens of centimeters. The length is typically in the range of about a meter to several meters. Each longitudinal member 720, 721 has at least one end - a first end 730, 731 - which is suitable for being rigidly attached to a corresponding coupling 740. In practice, the second end (not shown) is typically also suitable for being rigidly attached to a further corresponding coupling (not shown).

- a coupling 740 comprising an inner bore with an inner screw-thread over at least a portion of the inner bore, here depicted as being rigidly attached to each member 720, 721. The first end 730, 731 of the members 720, 721 comprises an outer screwthread, corresponding to the inner screw-thread of the coupling 740 inner bore. Rigid attachment is created by inserting the first end 730, 731 into the inner bore of the coupling 740 and rotating.

- the longitudinal member 720 in FIG. 1A comprises an inner bore 725, is configured and arranged for the transport of grout during installation. Grout is a mixture of a fluid (typically water) with a cement. The mixture optionally comprises a sand and/or a gravel. In this example, the longitudinal member 720 also comprises an outer screw thread corresponding to the inner screw thread of the coupling 740. Optionally, portions may have a relatively smooth surface.

- the longitudinal member 721 in FIG. IB does not comprise an inner bore. In this example, the longitudinal member 721 also comprises ribs on its outer surface to increase the transfer of longitudinal forces to the material (not depicted) into which it is to be secured.

Such construction ties (or anchors) are typically used in hydraulic engineering projects and constructions, such as sheet pile walls, river bank or dyke reinforcements, and quay or harbour walls. They may also used, for example, for building pits, cofferdams and other earth-retaining constructions. They may also be configured as anchor piles, which may be used for concrete structures under groundwater level, such as in basements, underpasses and railway underpasses.

Optionally, the coupling 740 may further comprise one or more inner stops 745 to limit the degree of insertion of the first end 730, 731.

Two methods of tie (anchor) installation are particularly relevant for the invention described in this disclosure:

1. Self-drilling grout injection anchors. Longitudinal members 720 with an inner bore 725 may be installed in this way. Hollow couplings 740 may be used to rigidly attach the members 720 together to form a hollow anchor of any desired length, through which grout is injected. A drill head is attached to the first member 720, and when the required depth for the start of the grout mass (or grout body) is reached, grout is injected through the hollow anchor. Drilling is continued, and when the final depth for the anchor is reached, the grout injection is stopped. The grout mass is allowed to harden, securing the construction tie (anchor). Typically, a length of the construction tie 700 is not encased in the grout mass, so that it may be prestressed. Diameters of the members 720 are typically 30mm to 200mm, with a wall thickness of 3mm to 30mm. By rigidly attaching members 720 to each other using couplings 740, tie lengths of 1 meter to 12 meters, for example, may be installed.

2. Case-drilling grout anchors. Longitudinal members 721 without an inner bore, members 720 with an inner bore or strands (tendons) may be installed in this way. A drill casing having an inner diameter larger than the outer diameter of the construction tie 700, 701 is drilled to create a borehole of the desired depth. The construction tie 700, 701 is inserted into the drill casing, and grout is injected into the drill casing as the drill casing is withdrawn. The construction ties 700, 701 may also be installed using two concentric drill casings. The grout mass is allowed to harden, securing the construction tie (anchor). Typically, a length of the construction tie 700, 701 is not encased in the grout mass, so that it may be prestressed. Diameters of the solid (without an inner bore) members 721 are typically 20mm to 150mm. By rigidly attaching members 721 to each other using couplings 740, tie lengths of 10 meter to 25 meters, for example, may be installed.

The members 720, 721 are made from a suitable material, such as a corrosion resistant steel. In practice, the members 720, 721 also comprise at least one coating or barrier (not shown), to provide protection against corrosion. The coating or barrier may be, for example, a metal layer, such as steel, a tape, such as Denso tape, or a galvanization layer. The coating is typically applied during the manufacturing process. In practice, one or more coatings, of similar or different types, cover at least the portions of the members 720, 721 which are to be subjected to hostile conditions after installation.

In addition, the grout mass provides a corrosion barrier for grout anchors. For case-drilled anchors, a plastic tube, such as PVC, may also be used as an additional or alternative corrosion barrier.

Additionally, metal components of the anchors are usually of a larger diameter than strictly required so that sufficient strength is retained even if some corrosion does occur.

The longitudinal members 720, 721 typically have a round or oval transverse cross-section.

In general, the use of couplings 740 allows construction ties to be assembled at the installation location using pre-fabricated standard lengths, so that potentially any length may be provided. For example, when using grouted ties (or grouted tie-backs), ties of up to 80 meters long may be installed using 4-meter sections.

Rigid attachment of the couplings 740 to the conventional metal members 720, 721 must be performed carefully to avoid damage. The invention is based upon the insight that the installation of the couplings 740 is often the cause of poor corrosion protection of the tie 700, 701 because ingress of fluid, in particular water, into the inner bore can easily occur due to:

- damage to the coupling 740 and member 720, 721 coatings and barriers from the tooling used;

- not inserting the member 720, 721 far enough into the inner bore of the coupling 730, 731 to ensure a good seal;

- inserting the member 720, 721 too far into the inner bore of the coupling 730, 731, thereby reducing the insertion length of another member, or damaging the interface between the first end 730, 731 and the coupling 740; and

- damage to the coupling 740 and member 720, 721 coatings and barriers from insertion.

Hydraulic engineering projects and constructions, such as sheet pile walls, river bank or dyke reinforcements, and quay or harbour walls, are particularly sensitive due to the almost persistent presence of water.

A possible solution is to use a plurality of corrosion barriers and coatings, but this will increase the cost of the ties 700, 701. Another solution is to avoid the use of couplings 740, but that limits the length of construction tie 700, 701 which can be installed. A further solution is to use a plurality of strands (tendons) which may be provided on a drum or reel, but these ties are more complicated to install, a

An additional problem is that corrosion, whatever the cause, is difficult (and in some cases impossible) to monitor after installation of the tie 700, 701, particularly when it is installed into the ground. The norms and standards concerning corrosion protection usually require at least two corrosion barriers protecting the complete metal tie, 700, 701. The corrosion protection may then be monitored by measuring the electrical resistance - when the resistance is relatively high (and remains relatively high), it may be assumed that there is a low (or acceptable) degree of corrosion.

A possible improvement may be achieved by using a cheaper corrosion coating or barrier. PCT application WO 2016/115119 (referenced as WO2016 herein) describes the use of protective coatings for metallic elements to improve corrosion resistance. An elastomeric coating is applied using, for example a spray coating process or submersion as described in paragraphs [0081] to [0089], This coating may be between 025 and 2.54mm - paragraph [0054],

Elastomeric coating, particularly comprising a polyurethane and/or a polyurea are relatively inexpensive and provide a good protection against corrosion, as depicted in FIG. 31 ofWO2016.

The inventors have determined that the processes and coated members described in WO2016 are unsuitable to be used with conventional longitudinal metal members 720, 721 as depicted in FIG. 1A and IB. Corrosion resistance is reduced due to damage which almost always occurs during insertion of the first ends 730, 731 of the members 720, 721 into the couplings 740. as they are rigidly attached to each other.

The coated members as depicted in FIG. 3 WO2016 are flat-shaped with a series of curves (ribs) or zig-zags (Fig. 20 WO2016) to increase friction. No coupling is described in this disclosure or hinted at - couplings are not needed in WO2016 as these members are for a Mechanically Stabilized Earth construction, which is conventionally constructed by placing the wall with the reinforcing members in the desired location, and filling the earth in layers behind the wall, gradually covering the reinforcing members and compacting the soil as it is being filled. For the coated members of WO2016, the total length is available during installation for coating and inspection. As described in WO2016 paragraph [0090] touching up of the coating may even be carried out as required.

FIG. 2A depicts a longitudinal cross-section through an improved metal construction tie 100 comprising one or more improved couplings 300, configured and arranged to be rigidly connected to each other. FIG. 2B depicts a longitudinal crosssection through a further improved metal construction tie 120, comprising one or more further couplings 301, configured and arranged to be rigidly connected to each other. Each tie 100, 120 comprises:

- one or more improved longitudinal metal members 200, 201 having a first end 230, 231 for rigid attachment;

- one or more improved couplings 300 comprising an inner bore, configured and arranged to rigidly attach to the first end 230, 231 of the one or more members 200, 201 by insertion of the first end 230, 231 into the inner bore;

- a coupling corrosion barrier 400, encapsulating at least a portion of the one or more couplings 300;

- a member corrosion barrier 410, encapsulating at least a portion of the one or more members 200, 201 proximate the first end 230, 231;

- the coupling 400 and member 410 corrosion barriers being configured and arranged to engage after insertion of the first end 230, 231 such that the ingress of a fluid into the inner bore of the coupling 300 is resisted;

wherein both the coupling corrosion barrier 400 and member corrosion barrier 410 comprise an elastomeric layer.

Although the construction tie 100 and longitudinal members 200, 201 are described as ‘‘metal”, they do not need to be completely metal. “Metal” is used here to indicate that they comprise sufficient quantities of one or more corrosion-sensitive metals and/or alloys such that corrosion barriers are required to comply with an international standard (or at least recommended).

Examples of types of corrosion include: HIC (Hydrogen Induced Cracking), SCC (Stress Corrosion Cracking), CFG (Corrosion Fatigue Cracking), MIC (Microbiologically Induced Corrosion) and ALWC (Accelerated Low Water Corrosion).

Rigid attachment should be interpreted as being sufficiently rigid to allow installed of the construction tie 100, which depends on parameters such as the type of construction tie 100, the medium into which it is being installed, the expected operating lifetime and the forces that are to be transferred. In general, installation may require axial, transverse, rotational forces and combinations thereof - once these parameters are selected, the skilled person may determine the appropriate measures to ensure rigid attachment.

FIG. 2Aand 2B show the longitudinal members 200, 201 comprising a first end comprising an outer screw-thread, one or more couplings 300, comprising an inner bore with an inner screw-thread, configured and arranged to rigidly attach to the first end 230, 231 of the one or more members 200, 201 by insertion and rotation of the first end 230, 231 into the inner bore. This provides a particularly convenient form of rigid attachment which may be relatively easy to release, and provides a rigid attachment suitable for installation requiring rotational forces to be used.

The coupling 300 may be provided by applying a coupling corrosion barrier 400 according to the invention to a conventional coupling 740 as depicted in FIG. 1A and IB. To improve adhesion, the surface of the conventional coupling 740 may require an additional treatment, such as sandblasting or sanding, and/or the application of a coating, to improve adhesion of the coating. In addition, extra material may need to be added or removed to adapt the shape, particularly in the region where the member 200, 201 is inserted.

Optionally, the coupling 300 may comprise one or more inner stops 345 to limit the degree of insertion of the first end 230, 231 - these stops 345 may be formed as a ring (or plate) within the coupling or as more than one protrusion around the inner circumference of the coupling 300. These one or more inners stops 345 are further configured to limit the degree of insertion to optimize the engagement between member and corrosion barriers. Note that such inner stops 345 may be comprised in any of the embodiments of the invention described in the disclosure - they have been omitted from the figures to improve legibility.

The member 200, 201 may be provided by applying a coupling corrosion barrier 410 according to the invention to a conventional member 720, 721 as depicted in FIG. lAand IB. Similar to the coupling 300, additional treatments and/or coatings may be used, and additional material may need to be added or removed, particularly in the region of the first end 230, 231.

The figures in this disclosure depict embodiments using an outer screwthread on a longitudinal member and an inner screw-thread in a coupling to rigidly attach an improved coupling to an improved longitudinal member. However, the skilled person will realise that the same engagement may be modified to provide the same degree of corrosion protection when using other forms of rigid attachment, such as push-fitting. In that case, the one or more longitudinal metal members comprises a first end without an outer screw-thread, and the one or more coupling comprises an inner bore without a screw-thread, configured and arranged to rigidly attach to the first end of the one or more members by insertion and optionally rotation.

Similarly, other forms of rigid attachment may be used, such as gluing, soldering, welding, flare couplings, flange couplings, crimp couplings, sleeve couplings, compression couplings, outer-screw threading on a coupling with inner screw threading of a longitudinal member, and any combination thereof.

A coupling 300 may be used to rigidly couple two longitudinal members 200, 201 together or it may be used to rigidly couple a longitudinal member 200, 201 to another component or element, such as a drill head (not shown).

The longitudinal member 200 in FIG. 2A comprises an inner bore 225. It may also be described as being substantially hollow, being substantially tubular or having a substantially-annular transverse cross-section. The inner bore 225 is typically configured and arranged for the transport of fluids during installation. Fluid is used here to describe any mixture or composition comprising one or more fluids. Fluids used include a flushing mixture, a grout mixture, a resin, a polymer, an adhesive or some combination thereof. Installation using a fluid, such as a grout mixture, is described below in relation to FIG. 5.

The improved coupling 300 in FIG. 2A also has an inner bore - when used with longitudinal member 200, the inner bore of the coupling may be configured and arranged for two purposes - to provide rigid attachment of the longitudinal member 200 and to provide a fluid communication channel between the inner bore 225 of the longitudinal member 200 and another component or element, such as a drill head or further longitudinal member.

The longitudinal member 200 in FIG. 2A comprises an outer screw-thread over substantially its whole length, and not just at the first end (for rigid attachment to the coupling). The screw-thread over substantially the whole length may be the same as the one used for rigid attachment, or it may be different. The same screw-thread is advantageous in the manufacturing process as any length of longitudinal member may be provided from the same threaded metal rods. In addition, the outer screw-thread is configured and arranged to increase the transfer of longitudinal forces to the material (not depicted) into which it is to be secured. Optionally, portions may have a relatively smooth surface. It may be advantageous to use a different thread for the rigid attachment, allowing a larger pitch or more protruding thread ridges to be used for securing the anchor.

- the member corrosion barrier 410 in FIG. 2A applied to the outer screwthread is depicted as flat on its outer surface, having completely filled the screw-thread ridges. This is only one possibility - in practice, the member corrosion barrier 410 may be of substantially even thickness over the length of the longitudinal member 200, making the outer-surface of the corrosion barrier 410 an approximate representation of the member 200 outer screw-thread.

The longitudinal member 201 in FIG. 2B differs in that it comprises no inner bore 225. It may also be described as being substantially solid or having a substantially disc-like transverse cross-section. These may be advantageous as smaller solid cross-section dimensions may resist greater forces applied during installation and use compared to a similar cross-section which is hollow. It may be manufactured by applying a screw thread to at least a first end 231 of bar, such as a GEWI (Gewinde stab) bar and providing a corrosion barrier 410 according to the invention. Installation using a fluid, such as grout mixture, is still possible, when it is configured for use as a casedrilling anchor.

The improved coupling 300 in FIG. 2B is functionally the same as that depicted in FIG. 2A. In practice, there may be some small differences due to the need of accommodating a different type of longitudinal member 201. It is in general advantageous to standardize parts used during installation of different types of construction ties. Optionally, a coupling 300 may also be used which does not have a through bore, but one with a blind threaded hole. In this example, the longitudinal members 201 are not hollow, so a fluid communication through the coupling 300 is not required. If blind, threaded holes are used, then the inner stop 345 may not be required.

As depicted, the longitudinal member 201 in FIG. 2B comprises no outer screw-thread over substantially its whole length - it has ribs except for the first end 231, and optionally the second end, which are provided with an outer screw-thread, configured and arranged for rigid attachment. Optionally, a screw thread corresponding to the inner screw thread of the coupling 300 may be used on the outer surface of the longitudinal member 201 - this may be advantageous as using a corresponding thread reduces the need for adapters. Optionally, portions of the longitudinal members 201 may have a relatively smooth surface

The invention is also based on the further insight that a fluid-tight (or having a high degree of resistance to the ingress of a fluid) metal construction tie 100, 120 may be provided by:

making the connection between a longitudinal member 200, 201 and a coupling 300 fluid-tight using a corrosion barrier comprising an elastomeric layer;

- providing an elastomeric layer that is robust enough to be substantially undamaged or retaining a high degree of resistance to the ingress of a fluid) in spite of the actions required during insertion, such as drilling and inserting the member 200, 201 into the coupling 300; and

- providing a highly-effective corrosion barrier between the metal of the tie 100, 120 and any other element or component, such as a drill head, and the environment, such as the ground.

Although an elastomeric layer provides an advantageous and less expensive corrosion protection, it is not inherently suitable for use with couplings 300. The physical contact, and in some cases physical force, used for the insertion, may damage one or more of the corrosion barriers 400, 410. In many cases, fluid may enter the inner bore of the coupling 300 or enter into any spaces between the corrosion barriers 400, 410 and the outer surfaces of the members 200, 201, and/or the outer surfaces of the couplings 300. This results in an increased corrosion risk. This may occur during installation, or some time later. Although the inner bore 225 of a hollow tie 100 is typically filled with grout during installation, small spaces may still be present between the grout and the inner surfaces of the hollow members 200. Such spaces may also appear due to expansion and contraction of the tie 100 during use.

The corrosion protection is improved by using an elastomeric layer as part of the corrosion barrier for the couplings 300, and also for the corrosion barrier for the improved members 200, 201. In addition, the corrosion barriers 400, 410 are configured to engage with each other after insertion of the first end 230, 231 into the coupling 300.

Examples of this engagement of the corrosion barriers 400, 410 are further described below. Note that only embodiments with hollow members as depicted in FIG. 2A are described. However, all the embodiments of the invention may also be configured to function with the solid members depicted in FIG. 2B.

FIG. 3 A schematically depicts a first example of how the corrosion barriers 400, 410 depicted in FIG. 2A and 2B may be configured to engage. The features with the same numbering are the same as depicted in FIG. 2A and 2B.

A longitudinal cross-section is depicted through an improved coupling 302 that is rigidly attached to a longitudinal member 200 with a hollow 225.

The improved coupling 302 further comprises an additional sealing feature 420 comprising an elastomer - the coupling 302 comprises a rectangular recess 420 at the entrance to the inner bore, extending substantially over the whole circumference, such that after applying an elastomeric layer 401 to the coupling 302, a portion of the elastomer 401 is retained as an additional sealing feature 420.

This additional sealing feature 420 is configured and arranged to engage with a member corrosion barrier 410 after insertion of the member 200. In this example, the recess 420 and the degree of engagement between the corrosion barriers 401, 410 may be influenced by the dimensions and positioning of the recess 420.

The degree of engagement between the corrosion barriers 401, 410 may be influenced by the depth that the first end 230 is inserted into the threaded inner-bore of the coupling 302. This applies not only to this example of engagement, but also to the other examples provided in this disclosure. If not inserted enough, fluid may still be able to enter the inner bore of the coupling 302 or between the corrosion barrier and an outer metal surface. If inserted too far, one or both of the corrosion barriers 410, 410 may be damaged, providing a channel for fluid to enter. So the degree of corrosion resistance may be improved by using measures which improve the accuracy and repeatability with which the longitudinal members 200 are inserted into the couplings 302 for rigid connection.

One solution may be to measure the torque applied between the coupling 302 and the longitudinal member 200 - when the torque reaches a predetermined and/or monitored value, further rotation (and therefore further insertion) is stopped.

Additionally or alternatively, a fixed number of revolutions of the member 200 or partial revolutions may be performed during the insertion. When this predetermined and/or monitored number of revolutions has been, performed, further rotation (and therefore further insertion) is stopped.

Additionally or alternatively, further insertion may limited by providing an inner screw thread in the inner bore of the coupling 302 having a limited depth. In other words, the screw-thread of the coupling 302 inner bore does not need to go all the way through the coupling 302.

Additionally or alternatively, the screw-thread of the inner bore of the coupling 302 may comprise an inner stop 345 as depicted in FIG. 2A and 2B.

Alternatively or additionally, the first end 231 may be provided with a marking and/or mechanical stop - this may be used to control (or to check) the insertion depth into the coupling 302 inner bore. Typically, an operator will be present during installation of the tie 100.

Note that an excess of the elastomeric layer 401 comprised in the coupling corrosion protection 401 may be used to form the ring 420.

The longitudinal cross-section dimensions of the recess may be configured as required to provide the required degree of engagement and the degree of corrosion protection.

The recess 420 and the additional sealing feature 420 may typically have a longitudinal dimension (or depth of the recess 420 in the face of the coupling) in the longitudinal cross-section of up to two times the wall thickness of the hollow member 200. So for a wall thickness of 5mm, the longitudinal dimension is typically up to 10mm.

The radial dimension (or the difference between the inner and outer diameter of the ring 420) in the longitudinal cross-section may typically be up to one time the wall thickness of the hollow member 200. So for a wall thickness of 5mm, the radial dimension is typically up to 5mm. It is expected to be dependent on the wall thickness.

The range for the longitudinal dimension may be 1-10 mm and for the radial dimension 1-10 mm, resulting in an elastomer sealing feature 420 with dimensions in the range 1-10 mm by 1-10 mm. Preferred are dimensions of approximately 5 mm by mm.

FIG. 3B depicts a second example in longitudinal cross-section of how the corrosion barriers 400, 410 depicted in FIG. 2A and 2B may be configured to engage. The features with the same numbering are the same as depicted in FIG. 3 A.

The difference with FIG. 3 A is that the coupling 303 comprises a triangular recess 421 at the entrance to the inner bore instead of a rectangular recess. As in FIG. 3 A, it extends substantially over the whole circumference, such that after applying an elastomer 402 to the coupling 303, some of the elastomer 402 is retained as an additional sealing feature 421. In this example, the recess 421 and additional sealing feature 421 are approximately triangular in longitudinal cross-section, and the sealing feature 421 is approximately a ring in transverse cross-section.

An excess of elastomer 402 may used to form the ring 421.

The longitudinal cross-section dimensions of the recess 421 may be configured as required to provide the required degree of engagement and the degree of corrosion protection. They are similar to those discussed for FIG. 3A above. In this case, the recess 421 and the additional sealing feature 421 may typically have the longest longitudinal dimension (or depth of the recess 421 in the face of the coupling proximate the inner screw thread of the coupling 303) in the longitudinal cross-section of up to two times the wall thickness of the hollow member 200. So for a wall thickness of 5mm, the longest longitudinal dimension is typically up to 10mm.

The longest radial dimension (or the difference between the inner and outer diameter of the ring 421 proximate the face of the coupling 303) in the longitudinal cross-section may typically be up to one time the wall thickness of the hollow member 200. So for a wall thickness of 5mm, the radial dimension is typically up to 5mm. It is expected to be dependent on the wall thickness.

The range for the longitudinal dimension may be 1-10 mm and for the radial dimension 1-10 mm, resulting in an elastomer sealing feature 420 with dimensions in the range 1-10 mm by 1-10 mm. Preferred are dimensions of approximately 5 mm by mm for the perpendicular sides of the triangle in the longitudinal cross-section.

The skilled person will realise that many different longitudinal crosssections of recess 420, 421 are possible, including concave, circular, oval, polygonal.

FIG. 3C depicts a third example of how the corrosion barriers 400, 410 depicted in FIG. 2A and 2B may be configured to engage. The features with the same numbering are the same as depicted in FIG. 2A and FIG. 3A.

The longitudinal member 202 further comprises an additional sealing feature 422 comprising an elastomer - the member 202 comprises an additional ring 422 at the first end 230, positioned such that it will be at the entrance to the inner bore after correct insertion into the coupling 300. This additional ring 422 extends substantially over the whole circumference of the member 202. Although depicted as a symmetrical, any shape would be sufficient if it provides an excess of elastomer even irregular nonreproducible shapes - for example, just using an excess of elastomer at the first end 230. This additional sealing feature 422 is configured and arranged to engage with a coupling corrosion barrier 400 after insertion of the member 202.

Note that excess of elastomer 411 used for the member corrosion protection 411 may also be used for the ring 422, or a separate ring 422 of an elastomeric material may be added during the manufacturing process of the members. Additionally or alternatively, a separate ring 422 may be added during installation.

As depicted, the longitudinal cross-section of the ring 422 is approximately rectangular, and the transverse cross-section is a ring. The longitudinal cross-section dimensions of the ring 422 may be configured as required to provide the required degree of engagement and the degree of corrosion protection.

The ring 422 may typically have a longitudinal dimension (or depth of the ring 422 against the face of the coupling) in the longitudinal cross-section of up to two times the wall thickness of the hollow member 200. So for a wall thickness of approximately 5mm, the longitudinal dimension is typically up to 10mm.

The radial dimension (or the difference between the inner and outer diameter of the ring 422) in the longitudinal cross-section may typically be up to one time the wall thickness of the hollow member 200. So for a wall thickness of approximately 5mm, the radial dimension is typically up to 5mm. It is expected to be dependent on the wall thickness.

The range for the longitudinal dimension may be in the range 0.5 -10 mm by 1-10 mm.

The skilled person will realise that many different longitudinal crosssections of ring 422 including oval or circular (an O-ring), square, are possible.

FIG. 3D depicts a fourth example of how the corrosion barriers 400, 410 depicted in FIG. 2A and 2B may be configured to engage.

The coupling 305 further comprises an additional sealing feature 424 comprising an elastomer - the coupling 305 comprises an additional elastomeric seal, such as an O-ring 424 within a recess 424 within the inner bore, and extending substantially over the whole circumference of the inner bore. It is configured and arranged to seal around the first end 230 of the member 200 after it has been inserted into the coupling 305. This additional sealing feature 424 is configured and arranged to engage with the member 200 after insertion of the first end 231.

A separate ring 424 is depicted in FIG. 3D - it may be a ring of an elastomeric material, added during the manufacturing process. Alternatively, a separate ring 424 may be added during installation. It may also be a ring 424 made of a plastic, such as nylon or PVC. It may also be made of hemp.

The separate recessed ring 424 depicted in FIG. 3D may be advantageously used in combination with the improved couplings depicted in FIG. 3A, FIG. 3B and FIG. 3C described above.

The longitudinal cross-section dimensions may be configured as required to provide the required degree of engagement and the degree of corrosion protection.

The ring 424 may typically have a longitudinal dimension (or depth of the ring 424 in the face of the coupling) in the longitudinal cross-section of up to two times the wall thickness of the hollow member 200. So for a wall thickness of approximately 5mm, the longitudinal dimension is typically up to 10mm.

The radial dimension (or the difference between the inner and outer diameter of the ring 424) in the longitudinal cross-section may typically be up to one time the wall thickness of the hollow member 200. So for a wall thickness of approximately 5mm, the radial dimension is typically up to 5mm. It is expected to be dependent on the wall thickness.

The range for the longitudinal dimension may be 1-10 mm and for the radial dimension also l-10mm.

Additional sealing may be provided using a tape (such as PVC), a glue, a fibre (such as hemp) or any combination thereof applied onto the outer screw thread of the first end and/or the inner screw thread of the coupling.

The skilled person will realise that any of the improvements to the coupling corrosion barrier depicted in FIG. 3 A, 3B, and 3D, (and those described in the associated description above) may be combined with the improvements to the member protection barrier as depicted in FIG. 3C (and those described in the associated description above). In particular, the following combinations may be advantageous:

-FIG. 3Aand3C

- FIG. 3 A and 3D

-FIG. 3Aand3Cand 3D

- FIG. 3C and 3D

- FIG. 3B and 3C

- FIG. 3B and 3D

- FIG. 3B and 3C and 3D

As depicted in FIG 6 in longitudinal cross-section, a conventional metal drill head 750 may be rigidly attached to a conventional construction tie 700, as depicted in FIG. 1 A, to provide a drilling anchor. If the tie 700 remains installed after drilling, it is referred to as a self-drilling anchor. The conventional tie 700 comprises one or more longitudinal members 720 and one or more couplings 740. Similarly, the conventional tie 700 without a central bore, as depicted in FIG. IB, may also be rigidly attached to a conventional metal drill head 750.

Conventional drill heads 750 are typically made of steel, and are not provided with a corrosion barrier and/or coating. The longitudinal member depicted 720 comprises an inner bore - if that is used for fluid communication during installation, such as for grout, the drill head 750 preferably comprises one or more fluid apertures 760, configured and arranged to allow the fluid being injected into the inner bore of the member 720 to pass into the region around the drill head 750. In addition, during conventional installation of a self-drilling grout anchor, the installation process typically ends by the construction tie 700 (and the rigidly attached conventional drill head 750) being retracted slightly so that the drill head 750 may be covered completely in the grout, making it generally water tight. Unfortunately, this process does not produce a reliable corrosion barrier.

Any coatings and/or corrosion barriers applied to the outer surface of the drill head 750 are unlikely to remain undamaged after drilling into, for example, a soil, to a sufficient depth to install an anchor.

After installation of the conventional drilling anchor, an electrical conductivity may be measured between the longitudinal members 720 and ground. This provides a measurement of the effectiveness of any corrosion barriers - a lower conductivity (or higher resistance) indicating a higher degree of corrosion resistance.

Fig. 4A depicts an improved drilling anchor 130, which differs from the conventional drilling anchor depicted in FIG. 6 by:

- providing an improved coupling 550 made from a non-conducting (or low-conducting) material, such as Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW), also known as High-Modulus PolyEthylene (HMPE) or hakorit (HDPE or High Density Polyethylene). It may also be non-metallic; and

- providing an improved longitudinal member 200, 201, 202, comprising a member corrosion barrier 410, 411 as described above. For example, the member corrosion barrier 410 from FIG. 2 A (applied to an improved longitudinal member 200 having an inner bore 225) is depicted in FIG. 4A.

Using such a non-conducting (or low-conducting) material for the improved coupling 550, no corrosion of the improved coupling 550 is likely during use. In addition, one or more inner stops are provided (not shown) to separate the longitudinal members 720 such that direct electrical contact is reduced or preferably eliminated.

After installation of the improved drilling anchor 130, an electrical conductivity measurement would not be affected by the conductivity of any metal longitudinal members 720 and/or a metal drilling head 750 disposed at the distal end of the improved construction tie 130 beyond the non-conducting coupling 550.

Corrosion may also occur to a greater degree in the presence of stray electrical currents. These currents are frequently present in the proximity of electrified transport systems, such as trains and trams. By using a non-conducting coupling 550, there is less conducting material in the ground for the stray currents to flow through. By using a non-conducting coupling 550 which is watertight connected to the PU layer 410 the tie is isolated from the ground and therefore stray currents are not able to flow through.

Alternatively, an improved coupling may also be provided using nonconducting (or low-conducting) material in forms similar to the conducting couplings 302, 303, 305 described above in relation to FIG. 3A, 3B, 3C and 3D. The associated coupling corrosion barriers and member corrosion barriers may also be similarly provided.

Fig. 4B depicts a further embodiment of an improved drilling anchor 130, which differs from the conventional drilling anchor depicted in FIG. 6 by:

- providing an improved member 520 made from a non-conducting (or low-conducting) material, such as Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW), also known as High-Modulus PolyEthylene (HMPE) or hakorit (HDPE or High Density Polyethylene). It may also be non-metallic;

- providing an improved longitudinal member 200, 201, 202, comprising a member corrosion barrier 410, 411 as described above. For example, the member corrosion barrier 410 from FIG. 2A (applied to an improved longitudinal member 200 having an inner bore 225) is depicted in FIG. 4A; and

- providing an associated improved coupling 300, 302, 303, 305 comprising a coupling corrosion barrier 400, 401, 402, 403, configured and arranged to engage with the member corrosion barrier. For example, the coupling corrosion barrier 400 from FIG. 2A (applied to an improved coupling 300) is depicted in FIG. 4B.

After installation of the further improved drilling anchor 130, an electrical conductivity measurement would not be affected by the conductivity of the metal drilling head 750 disposed at the distal end of the further improved construction tie 130 beyond the non-conducting member 520.

Alternatively, an improved coupling may also be provided using non conducting (or low-conducting) material in forms similar to the conducting couplings 302, 303, 305 described above in relation to FIG. 3A, 3B, 3C and 3D. The associated coupling corrosion barriers and member corrosion barriers may also be similarly provided.

Fig. 4C depicts a still further embodiment of an improved drilling anchor 130, which differs from the conventional drilling anchor depicted in FIG. 6 by:

- providing an improved drilling head 501 made from a non-conducting (or low-conducting) material, such as Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW), also known as high-Modulus PolyEthylene (HMPE) or hakorit (HDPE or High Density Polyethylene). It may also be non-metallic;

- providing two improved longitudinal members 200, 201, 202, comprising a member corrosion barrier 410, 411 as described above. For example, the member corrosion barrier 410 from FIG. 2A (applied to an improved longitudinal member 200 having an inner bore 225) is depicted in FIG. 4A; and

One of the improved longitudinal members 200, 201, 202 provides rigid attachment between the improved coupling 300 and the improved drilling head 701. The member corrosion barrier 410, 411 is configured to engage with the coupling corrosion barrier 400, 401, 402, 403.

No corrosion barrier is required for the improved drilling head 501 - this is advantageous as corrosion barriers are typically damaged during installation. Corrosion barriers comprising an elastomer are particularly sensitive to this damage during installation - by providing a non-conducting (or low-conducting) drilling head 501, corrosion barriers comprising an elastomer are only required on the conducting sections of the improved construction tie.

The low-conductive elements of FIG. 4A, 4B and 4C may also be combined - for example, a low-conductive drill head 501 rigidly connected to a lowconductive member 520; a low-conductive drill head 501 rigidly connected to a lowconductive member 520 rigidly connected to a low-conductive coupling 550; and a lowconductive drill head 501 rigidly connected to a conductive member 720, 200 rigidly connected to a low-conductive coupling 550.

The corrosion barriers 400, 410 are preferably applied with a composition comprising an elastomer such as polyurethane and/or polyurea (PU). Any suitable techniques, such as spraying or immersion in a bath, may be used. The elastomer may also be applied cold, as an elastomeric tape or by melting. Combinations of these techniques may be used for adjacent layers, or to apply the elastomer to different areas of the components. Preferably, the corrosion barriers are added during manufacturing, or as an additional preparation step prior to installation.

After the coating is applied, a corrosion barrier 400, 410, comprising an elastomeric layer is provided with an average thickness of approximately 1-2 mm, a maximum thickness of 8 mm, and a minimum thickness of 0.3mm.

Additionally or alternatively, one or more elastomeric layer may be provided during and/or after installation. For example, after rigidly attaching a coupling to a longitudinal member, an elastomer solution, such as a PU solution, may be directly applied to seal the joint.

Where an elastomeric layer has been provided prior to installation on a coupling on a longitudinal member, the layers may be melted, heated and/or soldered to improve the seal between the member corrosion barrier 410 and the coupling corrosion barrier 400.

FIG. 5 schematically illustrates the use of an improved hollow metal construction tie 130 as a self-drilling grout injected anchor or tie-back, which may be described as a metal construction tie 100 (as described above) further comprising a drill head 500, 501. In this example, the tie-back 130 is being installed into a medium 610, such as soil, after which it may be used to transfer applied tensile load (longitudinal force) into the medium 610. A cross-section though the medium 610 is depicted, and above it a zoomed view of the tip of the construction tie 130 is shown.

The metal construction tie 130 comprises a drill head 750, 501, one or more improved hollow longitudinal members 300 comprising a member corrosion barrier 410, and one or more improved hollow couplings 210 comprising a coupling corrosion barrier 400. Any suitable combination of coupling corrosion barrier 400 and member corrosion barrier 410 described in this disclosure may be used, as well as obvious equivalents. For clarity, the corrosion barriers 400, 410 are not depicted in FIG. 5.

The drill-head 750, 501 is rigidly attached to a first end of a longitudinal member 210 - a section of the first longitudinal member 210 is depicted partially in cross-section. Initially and/or during the insertion, additional longitudinal members will be rigidly attached to the rest of the construction tie 130 using couplings 210. For example, using longitudinal members with lengths of 4 to 7 meters, construction ties 130 up to 60 meters may be constructed.

During installation, an appropriate rotational force 660 is applied, usually to the part of the construction tie 130 that has not yet been inserted into the medium 610. The rigid attachment of the components transfers this rotational force 610 to the drill head 750, 501, allowing it to turn such that a longitudinal cavity 620 will be formed in the medium 610 as the construction tie 130 is being installed.

A tie-back may be inserted into the medium 610 at any angle to the horizontal, although angles of 15 degrees to 60 degrees are preferred for grouted tie-backs 130. After determining the desired position and angle for the grouted tie-back 130, the rotational force 660 is applied to the tie 10, turning the longitudinal members 210, the couplings 300, and the drill head 750, 501. Optionally, a mechanical force 650 may be applied axially to assist with the drilling.

As the construction tie 130 is rotationally 660 inserted into the medium 610, a longitudinal cavity 610 is formed by the drilling. The length of the construction tie 130 may be increased by rigidly attaching additional couplings 300 and additional longitudinal members 210 until the drill head 750, 501 is at the desired depth for the start of the grout 600 insertion. In this example, the longitudinal members 210 and couplings 300 comprise an inner bore 225 - in other words, they are hollow. The inner bore 225 is configured and arranged to provide an appropriate speed of flow for the grout 600 being used, and the one or more couplings 300 and one or more longitudinal members 210 form a continuous channel to allow grout 600 to flow from an injection point 630 to the drill head 750, 501.

The construction tie 130 further comprises a grout injector 630, usually in the part of the construction tie 130 that has not yet been inserted into the medium 610. The grout injector is in fluidic communication with the inner bore 225. The grout 600 injected preferably comprises a high percentage of water, and is preferably injected at high pressure. For example, 70% water / 30% cement may be used, injected at 10-20 bar. The injection of the grout may be preceded by a flushing step, using a very low percentage cement or even substantially water, to ensure that the flow of grout 600 will be relatively uninterrupted by flushing loose debris from the cavity 620.

Preferably the drill head 750, 501 comprises one or more grout aperture 510 such that the grout 600 is injected at the furthest insertion point of the construction tie 130.

During formation of the grout body, the construction tie 130 is rotated by applying the rotation force 660 to continue drilling. The grout 600 is injected under pressure, flowing through the inner bore 225 and through the one or more grout apertures 760 into the cavity 620. As the construction tie 130 rotates, the pressure of the grout 600 causes the grout 600 to mix with loose particles of the medium 610, and to fill the cavity 620 around the drill head end of the construction tie 130. Once the final depth is achieved, the operator stops the grout injection. If the longitudinal members 210 comprise an outer screw-thread on the outer surface, this screw-thread further improves the transfer of longitudinal forces to the grout mass (or body). Any convenient thread pitch may be used, such as l-20mm .

After the grout injection is stopped, the grout 600 is left to harden. This forms a grout body in the medium 600, which resists longitudinal forces (tensile load) applied to the construction tie 130. Using suitable brackets, additional longitudinal members, additional couplings and/or fixings, such as nuts, the construction tie 130 may be rigidly attached to a structure being secured and/or reinforced, such as a sheet pile wall or concrete constructions.

A self-drilling grout anchor may be used with loose media 610, such as soil, silt, clay and/or sand. The grout body may be formed along substantially the whole length of the construction tie 130, along one or more longitudinal members 210, along a single longitudinal member 210, along a portion of a longitudinal member 210, proximate the drill head 750, 501 or any combination thereof. The grout 600 may also be configured and arranged to provide a corrosion barrier as it isolates the metal construction tie 130 from the medium 610 into which it has been installed.

It may be advantageous to provide other fluids, such as a resin, a polymer, an adhesive or some combination thereof to improve the resistance to tensile forces and/or to improve the corrosion resistance.

Similarly, the improved hollow metal construction tie 130 depicted may be configured and arranged to be used as a grouted ground anchor by aligning the drill head 750, 500 to drill a cavity 620 vertically (or substantially vertically) into the ground.

Similarly, the improved metal construction tie 130 may be substantially solid (non-hollow), comprising GEWI (gewinde stab) longitudinal members. These GEWI members may comprise an outer-screw thread at the first and/or second end of the longitudinal member for rigid coupling. These may be used as grout anchors by first installing a suitably-dimensioned tube into the medium 610 by, for example, drilling. The improved metal construction tie 130 is then inserted into the inner bore of the tube, and grout is injected around the GEWI construction tie 130, filling the inner bore of the tube.

The skilled person will also realise that the construction ties according to the invention may also be configured and installed as case-drilling grout anchors.

Care should also be taken in handling the components coated with elastomer, in particular the longitudinal members and the couplings - they may become damaged during manufacturing, transport and/or installation. In general metal-to-metal contact should be avoided as any scratches may penetrate the elastomeric coating completely. Before any part of the construction tie is gripped, cushioning pads, such as rubber or plastic pads, should first be applied to the grippers.

It is recommended to measure the electrical conductivity of the construction tie after installation to check whether the elastomeric corrosion barriers have been compromised. It may also be advantageous to regularly repeat the measurement during the lifetime of the construction tie.

The descriptions thereof herein should not be understood to prescribe a fixed order of performing the method steps described therein. Rather the method steps may be performed in any order that is practicable. Similarly, the coding examples are used to explain the algorithm, and are not intended to represent the only implementations 5 of these algorithms - the person skilled in the art will be able to conceive many different ways to achieve the same functionality as provided by the embodiments described herein.

Although the present invention has been described in connection with specific exemplary embodiments, it should be understood that various changes, 10 substitutions, and alterations apparent to those skilled in the art can be made to the disclosed embodiments without departing from the spirit and scope of the invention as set forth in the appended claims.

Particularly advantageous embodiments include:

A. A metal construction tie (100, 120, 130) comprising:

- one or more longitudinal metal members (200, 201, 202) having a first end (230, 231) comprising an outer screw-thread;

- one or more couplings (300, 302, 303, 305) comprising an inner bore with an inner screw-thread, configured and arranged to rigidly attach to the first end (230, 231) of the one or more members (200, 201, 202) by insertion and rotation of the first end (230, 231) into the inner bore;

- a coupling corrosion barrier (400, 401, 402, 403), encapsulating at least a portion of the one or more couplings (300, 302, 303, 305);

- a member corrosion barrier (410, 411), encapsulating at least a portion of the one or more members (200, 201, 202) proximate the first end (230, 231);

- the coupling (400, 401, 402, 403) and member (410, 411) corrosion barriers being configured and arranged to engage after insertion of the first end (230, 231) such that the ingress of a fluid into the inner bore of the coupling (300, 302, 303, 305) is resisted;

wherein both the coupling (400, 401, 402, 403) and member (410, 411) corrosion barriers comprise an elastomeric layer.

B. A construction tie according to embodiment A, the tie (100, 120, 130) further comprising:

- a further longitudinal metal member (200, 201, 202) having a first end (230, 231) comprising an outer screw-thread;

- a further member corrosion barrier (410, 411), encapsulating at least a portion of the further member (200, 201, 202) proximate the first end (230), comprising an elastomeric layer;

wherein:

- the coupling (300, 302, 303, 305) is further configured and arranged to rigidly attach to the first end (230) of the second member (200) by insertion and rotation of the first end (230) into the inner bore;

- the coupling (400, 401, 402, 403) and further member (410, 411) corrosion barriers being configured and arranged to engage after insertion of the first end (230, 231) of the further member (200, 201, 202) such that the ingress of a fluid into the inner bore of the coupling (300, 302, 303, 305) is further resisted.

C. A construction tie according to embodiment A or B, wherein:

- the elastomeric layer comprises polyurea and/or polyurethane.

D. A construction tie according to any of the preceding embodiments A to C, wherein the coupling (300, 302, 303, 305) further comprises a recess (420, 421) at the entrance to the inner bore, extending substantially over the whole circumference of the inner bore, whereby the coupling corrosion barrier (400, 401, 402, 403) forms a sealing feature (420, 421) for engaging with a member corrosion barrier (410, 411).

E. A construction tie according to any of the preceding embodiments A to D, the tie (130) further comprising:

- a drill head (750, 501), comprising the one or more couplings (300, 302, 303, 305).

F. A construction tie according to embodiment E, wherein the drill head (750, 501) comprises a low-conductive material.

G. A construction tie according to any of the preceding embodiments A to F, wherein at least one longitudinal member (200, 201, 202) has an inner bore (225), configured and arranged for the transport of a fluid in a longitudinal direction;

and the inner bore of at least one coupling (300, 302, 303, 305) is further configured and arranged to provide a fluid communication channel between the inner bore (225) of the at least one longitudinal member (200, 201, 202) and a further member (200, 201, 202).

H. A construction tie according to any of the preceding embodiments A to G, wherein the first end of a longitudinal member (200, 201, 202) further comprises an additional seal (422, 423), positioned to be outside the entrance to the inner bore after insertion into the coupling (300, 302, 303, 305), and extending substantially over the whole circumference of the member, configured to resist the ingress of a fluid into a cavity between the outer surface of a longitudinal member (200, 201, 202) and an inner surface of a coupling (300, 302, 303, 305), the additional seal comprising an O-ring, an elastomer, a tape, a glue, fibre, or any combination thereof

I. A construction tie according to any of the preceding embodiments A to H, wherein the one or more couplings (300, 302, 303, 305) comprise a low-conductive material.

J. A construction tie according to any of the preceding embodiments A to I, wherein the one or more members (200, 201, 202) comprise a low-conductive material.

K. A construction tie according to any of the preceding embodiments A to K, wherein the one or more couplings ((300, 302, 303, 305 ) are integrated with one or more longitudinal members (200, 201, 202).

L. A construction tie according to any of the preceding embodiments A to K, wherein the inner bore of the one or more couplings (300, 302, 303, 305) comprises an inner stop (345), configured and arranged to limit the insertion of a longitudinal member (200, 201, 202).

M. A construction tie according any of the preceding embodiments A to L, wherein the tie (100, 120, 130) comprises a low-conductive material of ultra-high-molecularweight polyethylene (UHMWPE, UHMW), High-Modulus PolyEthylene (HMPE) and/or hakorit (HOPE).

N. Use of a construction tie according to any of the preceding embodiments A to M as:

- a ground anchor, a tie-back, a soil nail, a grouted ground anchor, a grouted tieback, a sheet pile tie, a rock bolt, a pile, a micro pile, a mini pile, a lifting bolt, a spandrel wall tie, a reinforcement or any combination thereof.

REFERENCE NUMBERS USED IN DRAWINGS

100	improved metal construction tie (inner bore or hollow)
120	improved metal construction tie (no inner bore or solid)
130	improved metal construction tie (inner bore) comprising drill head 200 longitudinal metal member (inner bore or hollow)
201	longitudinal metal member (no inner bore or solid))
202	longitudinal metal member (inner bore) - elastomer ring
230	first end (inner bore or hollow)
231	first end (no inner bore or solid)
250	longitudinal non-metal member
300	improved coupling (inner bore or hollow and no inner bore or solid)
302	improved coupling - with rectangular recess (or notch)
303	improved coupling - with triangular recess (or notch)
305	improved coupling (screw thread) - with O-ring groove
345	inner stop
400	a coupling corrosion barrier
401	first variant of coupling corrosion barrier (rectangular recess)
402	second variant of coupling corrosion barrier (triangular recess)
403	third variant of coupling corrosion barrier (O-ring)
410	a member corrosion barrier
411	member corrosion barrier with elastomer ring
420	additional sealing feature (rectangular)
421	additional sealing feature (triangular)
422	additional sealing feature (ring)
424	additional sealing feature (O-ring within a recess in coupling)
425	additional sealing feature (tape between inner thread of coupling and outer

thread of first end)

426	additional sealing feature (O-ring within a recess in first end)
427	additional sealing feature (rectangular recess in first end)
501	a non-conducting drill head
520	a non-conducting member
550	a non-conducting coupling

conventional metal construction tie (inner bore or hollow) further conventional metal construction tie (no inner bore or solid) conventional longitudinal metal members (inner bore or hollow) conventional longitudinal metal member (no inner bore or solid) inner bore or hollow first end of conventional member (inner bore or hollow) first end of conventional member (no inner bore or solid) conventional coupling with screw-thread inner stop a metal drill head fluid aperture

Claims

A metal mounting anchor (100, 120, 130) comprising:

- one or more metal elongated elements (200, 201, 202) with a first end (230, 231) provided with an external screw thread;

- one or more couplings (300, 302, 303, 305) with an inner cavity with an internal thread, configured to be securely attached to the first end (230, 231) of one or more elements (200, 201, 202) by inserting and rotating the first end (230, 231) into the inner bore;

- a first corrosion protection (400, 401, 402, 403) enclosing at least part of the one or more couplings (300, 302, 303, 305);

- a second corrosion protection (410, 411) enclosing at least a portion of the first end of one or more elements (200, 201, 202);

- in which the first corrosion protection (400, 401, 402, 403) and the second corrosion protection (410, 411) are configured to interlock after insertion of the first end (230, 231) such that a liquid penetrates into the inner cavity of the coupling (300, 302, 303, 305) is obstructed;

and wherein both the first (400, 401, 402, 402, 403) and the second (410, 411) corrosion protection contain an elastomer layer.

A mounting anchor according to claim 1, the mounting anchor (100, 120, 130) further comprising:

- a further metal elongated element (200, 201, 202) with a first end (230, 231) provided with an external screw thread;

- a third corrosion protection (410, 411), which encloses at least part of the first end of the further element (200, 201, 202), and contains an elastomer layer;

wherein the coupling (300, 302, 303, 305) is further configured to be securely attached to the first end (230, 231) of the further element (200, 201, 202) through the first end (230, 231) to insert and rotate the inner bore;

and wherein the first corrosion protection (400, 401, 402, 403) and second corrosion protection (410, 411) are configured to interlock after insertion of the first end (230, 231) such that a liquid penetrates into the inner cavity of the coupling (300, 302, 303, 305) is further obstructed.

A fastening anchor according to claim 1 or claim 2, wherein:

- the elastomer layer contains polyurea and / or polyurethane.

A mounting anchor according to claim 1, wherein the coupling (300, 302, 303, 305) further includes a recess (420, 421) near the entrance to the inner cavity which extends the entire circumference of the inner cavity, the first corrosion protection (400, 401, 402, 403) forms a seal (420, 421) to engage the second corrosion protection (410, 411).

A mounting anchor according to claim 1, the anchor (130) further comprising:

- a drill bit (750, 501), comprising one or more couplings (300, 302, 303, 305).

A mounting anchor according to claim 5, wherein the drill bit (750, 501) contains a layer of conductive material.

A mounting anchor according to any preceding claim, wherein at least one metal elongated member (200, 201, 202) has an inner cavity (225) configured to carry a longitudinal fluid;

and the inner cavity of at least one coupling (300, 302, 303, 305) is further configured to provide a fluid channel between the inner cavity (225) between at least one metal elongated element (200, 201, 202) and further element (200 , 201, 202).

A mounting anchor according to any preceding claim, wherein the first end (230, 231) of an elongated member (200, 201, 202) further comprises an additional seal (422, 423) positioned such that the seal (422, 423 ) after insertion into the coupling (300, 302, 303, 305) is near the entrance to the inner cavity, and extends over the entire circumference of the elongated member (200, 201, 202) configured to allow the ingress of a fluid in a cavity between the outer surface of the elongated member (200, 201, 202) and an inner surface of a coupling (300, 302, 303, 305), the additional seal comprising an Oring, an elastomer, a tape, an adhesive , fiber or a combination thereof.

A mounting anchor according to any one of the preceding claims, wherein the one or more couplings (300, 302, 303, 305) contain a low-conductivity material.

A mounting anchor according to any one of the preceding claims, wherein the one or more elongated elements (200, 201, 202) contain a low-conductivity material.

A mounting anchor according to any one of the preceding claims, wherein the one or more couplings (300, 302, 303, 305) are integrated with one or more elongated elements (200, 201, 202).

A mounting anchor according to any preceding claim, wherein the inner cavity of the one or more couplings (300, 302, 303, 305) includes an inner stop (345) configured to insert an elongated member (200, 201, 202) to hinder.

A mounting anchor according to any preceding claim, wherein the anchor (100, 120, 130) contains a low conductivity material of ultra high molecular weight polyethylene (UHMWPE, UHMWW), high modulus polyethylene (HMPE) and / or hakorit (HDPE ).

Use of a fixing anchor according to any one of the preceding claims, if:

- a ground anchor, an anchor, a ground nail, a grout anchor, a ground grout anchor, a rock anchor, a sheet pile clamp, a rock bolt, a pole, a pile wall clamp, a micropile, a mini post, a lifting bolt, a spandrel, a reinforcement or a combination thereof .