Anchor bolt  Anchor bolts are used to connect structural and non-structural elements to the concrete. The connection is made by an assembling of different components such as: anchor bolts (also named fasteners), steel plates, stiffeners. Anchor bolts transfer different types of load: tension forces and shear forces. A connection between structural elements can be represented by steel column attached to reinforced concrete foundation. Whereas, a common case of non-structural element attached to a structural one is represented by the connection between a facade system and a reinforced concrete wall. The simplest – and strongest – form of anchor bolt is cast-in-place, with its embedded end consisting of a standard hexagonal head bolt and washer, 90-bend, or some sort of forged or welded flange (see also Stud welding). The last are used in concrete-steel composite structures as shear connectors. Other uses include anchoring machines to poured concrete floors and buildings to their concrete foundations. Various typically disposable aids, mainly of plastic, are produced to secure and align cast-in-place anchors prior to concrete placement. Moreover, their position must also be coordinated with the reinforcement layout. Different types of cast-in-place anchors might be distinguished:   For all the type of the cast-in-place anchors, the load-transfer mechanisms is the mechanical interlock, i.e. the embedded part of the anchors in concrete transfers and the applied load (axial or shear) via bearing pressure at the contact zone. At failure conditions, the level of bearing pressure can be higher than 10 times the concrete compressive strength, if a pure tension force is transferred. Cast-in-place type anchors are also utilized in masonry applications, placed in wet mortar joints during the laying of brick and cast blocks (CMUs). Post-installed anchors can be installed in any position of hardened concrete after a drilling operation. A distinction is made according to their principle of operation. The force-transfer mechanism is based on friction mechanical interlock guaranteed by expansion forces. They can be furtherly divided into two categories:   The force-transfer mechanism is based on mechanical interlock. A special drilling operation allows to create a contact surface between the anchor head and the hole's wall where bearing stresses are exchanged. The force-transfer mechanism is based on bond stresses provided by binding organic materials. Both Ribbed bars and threaded rods can be used and a change of the local bond mechanism can be appreciated experimentally. In ribbed bars the resistance is prevalently due to shear behavior of concrete between the ribs whereas for threaded rods friction prevails.(see also Anchorage in reinforced concrete).