Multiple terms are used for ground anchors such as rock anchors, tiedown anchors, tieback anchors, soil anchors, earth anchors and foundation anchors. They all do the same thing – transfer load (primarily tension) from a super structure into the ground. The term used perhaps depends upon the context and/or the ground conditions.
Rock anchors are often used for new communication tower construction or tower retrofits situated on a remote mountain top. The tower foundations are founded in bedrock that is at or very near the surface. The tower leg foundations rely on rock anchors for increased stability. Rock anchors can achieve high load capacity and can be drilled and installed with mobile equipment.
Tiedown anchors are often used for subsurface structures build at or below the groundwater table to resist buoyant uplift forces present when groundwater levels are higher.
Tieback anchors generally refer to an anchor that is pre-tensioned to preemptively reduce movement once the load is applied. Any rock anchor or tiedown anchor can also be post-tensioned. The term tieback anchor commonly refers to post-tensioned anchors used in earth retention systems.
Soil anchor is used interchangeably with tiedown anchor or tieback anchor, and as the name implies, usually indicates the anchor is founded in soil.
Earth anchor is used interchangeably with tiedown anchor or tieback anchor, and as the name implies, usually indicates the anchor is founded in soil.
Micropile can also be a term that is interchangeable but usually implies there is a significant compression load from the superstructure.
The drilling means and methods varies and depends upon the ground conditions, i.e. rock, soil, ground with cobbles & boulders, mixed ground conditions, the presence of groundwater, and if the drill hole will stay open or if the drill hole will require casing. A steel bar or tendon is installed in the drill hole and neat cement grout is then pumped into the bottom of the drill hole until the drill hole is filled. Other means and methods of installation include helical systems and mechanical anchor systems.
Design and successful construction ground anchor systems requires knowledge and understanding of the ground conditions and selecting the most appropriate means and methods and also considering site access constraints. Geo Craft Builders has decades of experience and experience on many high profile projects.
If you would like more information about ground anchor systems reach out to us at Geo Craft Builders today. We look forward to working with you.