Wire Strand or Bar Tendons for geotechnical application
Geotechnical systems, Ground Anchors
Anchors are always used in situations in which high tensile forces must be transferred into the ground. Typical applications include, for example, anchoring of excavation sheeting or retaining walls, slope and rock stabilization or anchoring for bridge abutments or wind turbine masts.
A prestressed grouted ground anchor is a structural element installed in soil or rock that is used to transmit an applied tensile load into the ground. Grouted ground anchors, referenced simply as ground anchors, are installed in grout filled drill holes.
Grouted ground anchors are also referred to as “tiebacks”. The basic components of a grouted ground anchor include the:
These and other components of a ground anchor. The anchorage is the combined system of anchor head, bearing plate, and trumpet that can transmit the prestressing force from the prestressing steel (bar or strand) to the ground surface or the supported structure.
Anchorage components for a bar tendon
Anchorage components for a bar tendon for Strand anchors
The unbonded length is that portion of the prestressing steel that is free to elongate elastically and transfer the resisting force from the bond length to the structure. A bond breaker is a smooth plastic sleeve that is placed over the tendon in the unbonded length to prevent the prestressing steel from bonding to the surrounding grout. It enables the prestressing steel in the unbonded length to elongate without obstruction during testing and stressing and leaves the prestressing steel unbonded after lock-off. The tendon bond length is that length of the prestressing steel that is bonded to the grout and can transmit the applied tensile load into the ground. The anchor bond length should be located behind the critical failure surface.
A portion of the complete ground anchor assembly is referred to as the tendon. The tendon includes
the prestressing steel element (strands or bars), corrosion protection, sheaths (also referred to as sheathings), centralizers, and spacers, but specifically excludes the grout. The definition of a tendon, as described in PTI (1996), also includes the anchorage; however, it is assumed herein that the tendon does not include the anchorage. The sheath is a smooth or corrugated pipe or tube that protects the prestressing steel in the unbonded length from corrosion. Centralizers position the
tendon in the drill hole such that the specified minimum grout cover is achieved around the tendon. For multiple element tendons, spacers are used to separate the strands or bars of the tendons so that each element is adequately bonded to the anchor grout. The grout is a Portland cement-based mixture that provides load transfer from the tendon to the ground and provides corrosion protection for the tendon.
Typical appplication
Corrosion protection of soil- and rock nails:
Esolution construction and Engineering provides two solution for the ground anchors, Self-drilling hollow bars or Solid Bar tendons available for both Permenant and Temporary application with service life ranges of 2 years, 7 Years and 100 years, the difference is the necessary corossion protection of the bars to remain in service life targeted, for any inquiries please contact us on info@esolution-pt.com