Tieback (geotechnical)

An anchor, also called pre-stressed anchor, is a built-in element that transmits a tensile force applied to a viable layer in the subsoil. It consists of a steel tension member, which is installed in a wellbore. The tension member is anchored at one end in the ground by cement mortar pressed, the so-called grout. At the other end there is an anchor head, which is supported by the structure to be anchored biased, i.e., a tensile force in the tension member initiated.

Anchors are used in soil and rock. In civil engineering, they serve for example for rear support of excavation and protection of floor panels against uplift due to groundwater.

History

In prestressed rock anchors were first held in 1935 when dam construction in Algeria its application.

Anchors for loose soils were developed in the late 1950s to the rear anchoring large and deep excavation walls among other things, by Karl Heinz Bauer. For the first time they were used in 1958 in Munich in an excavation for a building of the Bayerischer Rundfunk. Originally the pile wall of the excavation with steel rods in parallel produced this well shafts should be anchored. However, the exporting company had problems to make the fountain. Peasant was then the anchors in concrete directly in the gravel floor. With this in 1958 by Bauer patent pending construction method of the tie rod for anchoring of components in soil pits could be produced without the previously necessary bracing with the help of logs or steel struts. Thus, the disability accounted for in the construction work and it was possible excavation walls, one or more layers of anchors to produce. One of the known examples use constitutes your back anchoring the foundations of the tent roof of the Olympic Park in Munich

Features

A conventional anchor consists of the anchor head, the tension member, usually prestressing steel, and the grout around the Zuggliedende. About a complicated clamping and testing system, the respective force-insertion can be controlled. The procedure is now technically standardized in Germany in 1537 in EN and has a General approval. The power transmission takes place over the mantle of the grout into the ground and is due to the bracing of the grout in the ground.

The construction knows both permanent anchors (or permanent anchors) as well as short-term anchor (or temporary anchor). Permanent anchors are an anchoring with a useful life of at least 100 years. You must, therefore, one of the intended working life have appropriate corrosion protection. In addition, a permanent monitoring of the force in the tension member is often required. Short-term anchors may be usually only a maximum of two years in use.

You can choose from among others Strand and anchor rod.