Ground anchors or tie-backs are versatile devices used to hold, restrain and support building and civil engineering structures either temporarily or permanently. The method of installation varies depending upon the ground conditions.
In temporary ground anchoring of basement walls, holes are bored using rotary or percussion techniques with or without casing, and bare wire strand is grouted into the hole. Typically the anchor is then tensioned and locked off against a head plate. Once the basement slabs are completed the temporary anchors are de-stressed, blocks and plates are removed and patched on the wall. Where necessary, they may be completely removed.
Permanent anchoring is more common in civil applications such as water infrastructure and wind farms. The key points of difference are the corrosion protection to provide extended design life and anchor head detailing to enable check and re-stressing.