WE MAKE INFRASTRUCTURE SAFER, STRONGER, AND SMARTER. ANCHOR SYSTEMS

Contents About us 4 Anchoring Systems 5 Basic Concept 5 DYWIDAG Bar Anchors 6 Basic Concept 6 Threadbar Data 8 Accessories 9 DYWIDAG Strand Anchors

About us DYWIDAG-Systems International are a specialist geotechnical systems supplier with expert technical knowledge and longstanding experience in pre-stressed anchoring systems. Anchors are used throughout infrastructure development to provide restraint for a range of structures from hydro-electric dams to sheet pile walls. The anchoring systems developed by DYWIDAG-Systems International lead the industry in this specialist construction application. Our comprehensive approach allows us to provide our customers with technical advise based on the requirements and characteristics of the whole...

Anchoring Systems Basic Concept Ground anchors are defined as a pre-stressed element which actively contribute to the stability of the structure throughout its design life. Unlike passive elements the performance of the anchor is critical to the stability of the structure. Force is applied to the surface of the wall or slab by pre-stressing the anchor using a stressing jack to elongate the tendon, once the necessary load has been established, the anchor is “locked off” at the head. From this moment onwards the anchor will be applying a compressive load to the structure to arrest movement. To...

DYWIDAG Bar Anchors Basic Concept Bar Anchors are formed from a solid steel threadbar which can be installed in coupled sections to achieve the desired design depth. Bar anchors are the simplest type of anchor with a long history of use. The modular nature of the bar anchor system means that installation, although sometimes challenging due to the length of the individual bars, is straightforward. In an unrestricted working area, individual bar lengths of up to 12m can be installed. In areas of restricted access, bar lengths can be tailored to meet the site specific requirements of the project....

DYWIDAG Bar Anchors GEWI® GEWI® Steel High Yield Threadbar is a high tensile alloy steel bar which features a coarse left-hand thread over its full length. The system is proven worldwide and offers versatility in a range of applications. 16 - 50mm bars can be welded using appropriate industry practices relative to the carbon content of the steel. Welding of the higher grade 63.5mm diameter bar is also acceptable with additional measures. Manufactured in accordance with the German Certificate of Approval (Deutsches Institut für Bautechnik), the system also offers general conformance with BS 4449...

DYWIDAG Bar Anchors Threadbar Data GEWI® Threadbar Nominal Diameter Steel Grade Ultimate Strength Yield Strength CrossSectional Area Diameter Over Threads Thread Pitch GEWI® Plus Threadbar Nominal Diameter Steel Grade Ultimate Strength Yield Strength CrossSectional Area Diameter Over Threads Thread Pitch Prestressing Steel Threadbar Nominal Diameter Steel Grade CrossSectional Area Diameter Over Threads Thread Pitch

DYWIDAG Bar Anchors Accessories GEWI® Accessories Nominal Diameter Static Coupler GEWI® Plus Accessories Nominal Diameter Static Coupler Prestressing Steel Accessories Nominal Diameter Static Coupler

DYWIDAG Strand Anchors Basic Concept Strand anchors are assembled from flexible steel wire strand. These anchors are made to order and are installed in one continuous length. into a borehole; this is particularly useful when working in tunnels or basements. Strand anchors are most commonly used when anchor lengths exceed 20m or when access restrictions prevent solid threadbars from being used. Strand anchors are supplied to site coiled with a grouted bond length. Strand anchors can be unwound directly Strand anchors also provide a solution when anchor capacities exceed the strength of the threadbar...

DYWIDAG Strand Anchors Multi-Stage Strand Anchors Basic Concept The multi-stage strand anchor has been developed from the need to achieve greater anchor loads in poor ground conditions. It offers uniform distribution of load over the full bond length in addition to efficient utilisation of the in-situ ground strength. Conventional ground anchors are limited to a maximum fixed length of 10m (BS 8081); extending the conventional fixed length will not produce a gain in load carrying capacity, because any higher loading would induce progressive de-bonding from the proximal end of the fixed anchor...

Double Corrosion Protection Basic Concept BS8081 defines permanent anchors as installations with lifespans in excess of 2 years. In order to achieve this status, sufficient corrosion protection needs to be provided. To ensure durability throughout the working life of each anchor, double corrosion protection needs to be provided. Double corrosion protection (DCP) is defined in BS8081 and consists of factory pre-grouted encapsulation of the bar within a corrugated plastic sheath. DYWIDAG DCP Anchors are capable of providing consistent performance for 120 years. The specialist coupler and head assembly...

DYWIDAG Removable Strand Anchors Basic Concept DYWIDAG removable strand anchors are based on a multi-stage anchor with a compression unit at the distal end of each stage. The full length of the anchor, other than the compression unit, is de-bonded. When the anchor is stressed, the compression unit reacts against the underside of the grout column, putting it into compression: hence the term “compression unit”. At the base of each compression unit is a rupture point formed from a strand fixing with a known failure load. Stressing the anchor in excess of that failure load causes the strand to break...

GFRP Cuttable Anchors Basic Concept When temporary anchors are installed into ground that has potential for future development, an alternative solution to the removable anchor system is the cuttable anchor. Glass Fiber Reinforced Polymer bar has been used for passive systems such as rock bolts and soil nails for some time; however, as a material which is easily cut, it can provide specific qualities desirable temporary pre-stressed systems too. GFRP can take large tensile forces and so lends itself to ground anchoring however due to the materials reduced shear strength compared to steel, the...