Here you have several picture of an anchor cage we assembled a few days ago.
The anchor cage is a system conceived to transfer the loads to the foundation more effectively, anchoring the tower to the foundation.
It is made of two ring-shaped steel plates, an anchor plate and a load distribution plate, secured by anchor bolts.
Bolts are tensioned to a standard value, or sometime to different values depending on the calculation made for every foundation.
This system has been used for many years – I think that one of the first manufacturer to use it was Nordex in 2000.
As you can see we received the bolts and the distance pipes in several wood boxes, together with nuts and washers – all manufactured by Cooper and Turner in the UK.
Other items we received where the template to help the workers in the mounting operations, the foam to protect the top of the bolts during grouting and the legs of the cage.
The assembly operation take several hours: the two halves are assembled separately and than joined together below using a fastener and above using a fishplate (there is a picture with the detail of the operation).
There is a tolerance of a few millimeters, so the operation can be time consuming as several manoeuvres with the crane are necessary. We double checked each time using a laser level.