Bar Anchors

Bar anchors offer the following advantages:

  •  Easy handling of bars (simple stressing and de-stressing process)
  • Anchor length can be easily adjusted on site. (bars can be cut to length or joined at any point using couplers)
  • High shear bond between threaded bars and cement grout
  • Complete flexibility in anchor working loads due to extensive range of available cross-sections and steel grades.

Bar anchors are available in the following design variants:

  • temporary bar anchors
  • permanent bar anchors
  • removable bar anchorsAvailable steel grades:

 

Available steel grades:

BSt 500 / 550 ∅ 16 - 50 & 78 mm
S 555 / 700 ∅ 57,5 & 63,5 mm
S 670 / 800 ∅ 18 - 75 mm
St | 950 / 1050 | ∅ 18 - 47 mm

Temporary Bar Anchors

This type of anchor is generally designed for a lifespan up to two years. For temporary bar anchors constructed of prestressing steel grade ST 950 / 1050 the intended application must, however, be analyzed in more detail. Despite the term "temporary" it may be necessary to apply some form of corrosion protection.

Temporary bar anchors consist of the following components:

Anker head Customized for different applications and site conditions

Bond length Also called "fixed anchor length", this represents the section of  the bar anchor  which transfers the tensile load to the ground.

Free anchor length This represents the elastic section of the bar anchor between bonded length bonded length  and anchor head that does not transfer any load to the surrounding soil.

Permanent Bar Anchors

This type of anchor is designed for permanent application. To ensure the durability of the permanent bar anchors, special attention must be given to the quality of corrosion protection (details can be found in the relevant Approval Certificates under Downloads).

 


 

Removable bar anchors

Typ 1

Removable bar anchors where only the bond length remains in the ground

With this type of removable anchor, the bond length and the free anchor length are made separately from each other and connected by means of a special sleeve joint generally at the production center. At the time of removal, the free anchor length is unscrewed from the special sleeve after the anchor has been destressed. The bond length of the anchor remains in the ground.

Fully removable bar anchors

Type 2

Fully removable bar anchors

Here the principle of a pressure pipe anchor is used. The anchor is confined for 2 meters at the base. This is fitted with 10 small pressure transfer elements, which remain in the soil but do not present an obstruction. The anchor rod is completely unscrewed. It should be noted that the maximum anchor  length si limited for both variants. Theoretically, a rod anchor can be coupled as required, but in practice the overall length should be selected so that only one rod has to be handled when unscrewing. Another aspect in the choice of anchor length is the rod diameter. The smaller the bar diameter, the greater the deflection (depending on the anchor inclination) and the more difficult it is to turn the bar in the installed and filled condition. In extreme cases, the bending deflection becomes so great that it is no longer possible to rotate the rod and therefore, the removal is no longer guaranteed.

It is recommended to use an easy-to-handle anchor length, which should be in the range between 12  and 18 m.

Special care must also be taken when installing this type of anchor.