Definition: (1) in prestressed concrete, to lock the stressed tendon in position so that it will retain its stressed condition; (2) in precast-concrete construction, to attach the precast units to the building frame; (3) in slabs-on-grade or walls, to fasten to rock or adjacent structures to prevent movement of the slab or wall with respect to the foundation, adjacent structure, or rock.
An anchor is a steel element either cast into concrete or post-installed into a hardened concrete member and used to transmit loads to the concrete. Cast-in anchors include headed bolds, hooked bolts (J- or L-bolt), and headed studs. Post-installed anchors include expansion anchors, undercut anchors, and adhesive anchors. Steel elements for adhesive anchors include threaded rods, deformed reinforcing bars, or internally threaded steel sleeves with external deformations. Anchor systems are typically used to connect two parts of a structure together or to connect a nonstructural item to the structure.