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.
We have a range of Threadbar systems suitable for use in anchoring applications. This ensures that an economic choice of tendon can be made. The main consideration is available space vs load capacity.
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.
Manufactured in accordance with the German Certificate of Approval (Deutsches Institut für Bautechnik), the system also offers general conformance with BS 4449 : 2005 (Steel for the Reinforcement of Concrete).
The minimum specified characteristic yield strength is 500N/mm2 for bar diameters 16 - 50mm and 555N/mm2 for the 57.5 - 63.5mm diameter bar.
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.
The most common sizes of GEWI® bar used in ground anchoring applications are 28 - 63.5mm. The GEWI® product comes with a full range of accessories including domed nuts, full strength couplers, bearing plates, steel protection caps and spacers.
Modulus of Elasticity
- E = 205,000N/mm2 +/- 5%
- Stock Lengths
- All bar diameters 12.0m. Tolerances +/- 100mm. Special lengths up to 18.0m are available to order.
All bar diameters can be cut to length to suit customer requirements orsupplied bent to BS 8666 : 2000.
DYWIDAG-Systems International has developed the GEWI®Plus systems to meet the challenges set by restrictions in construction space and higher demands on load capacities of steel elements.
GEWI®Plus offers an increase in strength compared to traditional GEWI® Threadbars. GEWI®Plus has a yield strength of 670N/mm2 – an increase of 34% and an ultimate strength of 800N/mm2 – an increase of 45%.
In instances where construction tolerances within a concrete column, precast segment or borehole are tight, the increased strength offered by GEWI®Plus can allow for bar sizes to be reduced subsequently, allowing for concrete cover requirements to be met or borehole sizes to become smaller.
Compared to GEWI®, GEWI®Plus can reduce the cross sectional area of steel required in a ground anchor pile or rock bolt by up to 25% due to the increased strength.
Despite the high strength, GEWI®Plus is not sensitive to stress crack corrosion and hydrogen induced embrittlement.
The robust GEWI®Plus thread is specially designed for rough site conditions. The right-hand thread over the full length offers the possibility to fix and couple the bars at any point.
GEWI®Plus is fully integrated in the ISO 9001 quality assurance system of DYWIDAG-Systems International.
DYWIDAG Prestressing Steel Threadbar is a high tensile alloy steel bar which features a coarse right-hand thread over its full length. The system is proven worldwide and offers versatility in a range of applications.
Manufactured in accordance with the German Certificate of Approval (Deutsches Institut für Bautechnik), the system also offers general conformance with BS 4486 : High Tensile Steel Bars for Prestressing of Concrete.
During the steel making process, the threadbars are hot rolled, quenched and tempered, followed by cold working and further tempering, to achieve the necessary performance.
DYWIDAG Prestressing Steel Threadbars, 15mm - 75mm Ø, are suitable for all static loading applications. Additionally, for posttensioning and dynamic applications, DYWIDAG Prestressing Steel Threadbars 26.5mm - 40mm Ø, offer a fatigue resistance in excess of 2 million load cycles over a tensile range of 630 - 682N/mm2 as specified in the European Technical Approval No. ETA - 05/0123 and ETAG 013. Stress relaxation when loaded to 70% fpu is less than 3.5% over a 1000 hour period in accordance with BS 4486.
The low relaxation characteristics combined with the high strength offered by prestressing steel make it ideal for anchoring applications.