Bar Anchors
Ground Anchors (also known as Grouted Anchors or Tie Back Anchors) are an active system (prestressed and locked off) that transmit applied tensile load into the ground. Due to prestressing, deformations are controlled - either minimized or eliminated. Ground Anchors are used for excavations next to existing structures in urban areas, rock & slope stabilization, dam construction, underground constructions and tiedown structures. Our ground anchor system complies with EN 1537, BS EN 1997-1 and BS 8081.Ground anchor consists of three components; anchor head (anchorage), free stressing (unbonded) length and bond length. Anchor head transmits the prestressing force from the tendon (threaded bar or strands) to the structure that needs to be anchored. Smooth sheathing (bond breaker from the surrounding grout) over free stressing length ensures that the tendon elongates and transfers the resisting force from the bond length to the supporting structure. Bond length transfers the applied tensile load into the soil.
Based on design working life, ground anchors can be classified into temporary (up to 2 years) and permanent (more than 100 years). Tendons used in a ground anchor system are threaded solid bar and strands.
Selection of ground anchors shall be based on several factors such as accessibility, application, length of anchor, etc.
Threaded Bar Anchors:
Temporary Bar Anchor: Threaded solid bar, hot rolled with continuous thread serves as the steel tendon. Anchorage consists of an anchor plate with steel trumpet and an anchor nut. Temporary anchors can be used where design working life is up to 2 years.Permanent Bar Anchors: For permanent applications, Double Corrosion Protection (DCP) system shall be used. Threaded bar placed inside a HDPE or PVC corrugated sheathing and factory grouted serves as the reinforcement bar (tendon). DCP anchor system offers double barrier against corrosion. Permanently sealed anchor head ensures desired durability for permanent application.
Benefits of Bar Anchors:
- Handling of bar anchors are easy from stressing and de-stressing point of view
- Anchor head is simple compared to a strand anchor head
- Steel bars can be cut and coupled without any additional threading at site to connect couplers
- Splicing of bars using coupler is easy
- Hot rolled threads with coarse pitch makes it screw-able in challenging site conditions, thus making it suitable for geotechnical applications
- High relative rib area provides maximum bond stress between steel bar and cement grout
Threaded Solid Bars are available in:
- 500/550: Ø16 - 75 mm
- 550/620: Ø20 - 75 mm
- 670/800: Ø18 - 75 mm
- 950/1050: Ø18 - 75 mm
