Device for activation of the skin friction of pile-like support members

The present invention relates to a device for activation of the skin friction of pile-like support members which are formed in hard rock. The apparatus comprises a device which is capable of reducing a height of the device when the device is loaded with a pressure force. By the load with the pressing force, a controlled reduction of a pole-like support member can be caused in the ground, which is sufficient for the activation of the skin friction on the pole-like support member. Moreover, the invention pile-like support members and structures comprising such a device and a method for activation of the skin friction of pile-like support members and a method for erecting a building concerned.