As already specified they are divided into two types:
All the strands of the anchor are simultaneously put under tension in a single block with their clamping wedges and a supporting plate. The range varies from 2 to 12 strands.
The heads used are the same as those used in structure cables and therefore tested in accordance to the current regulations, the steel from the beam bearing plates conform to the EN 10025 standards and are provided with the relative CE mark. It is specially used for dielectric anchors.
In a multiple head one head is used for each strand which produces the anchor. Up to 8 strands are normally used.
The heads have been checked and submitted to laboratory tests as prescribed by the current standards and the steel used conforms to the EN 10025 standards.