Infrastructure construction projects in the urban space, such as the Berlin North Vertical Power Link, face particular challenges. In densely populated areas like Berlin, very little room is available for the execution of construction projects. The Berlin North Vertical Power Link was therefore designated with ‘F’ in the Federal Requirements Plan, meaning that the implementation as an AC underground cable is planned as a pilot project. Based on a feasibility study, 50Hertz came to the conclusion that open trenching (for underground cable-laying) is hardly possible in Berlin. The result of the study suggests the tunnelling method over a distance of around 17 kilometres and an overhead line or underground cable for the remaining 3 km.
For the tunnel construction, shafts are needed at regular intervals. These will be used for logistical purposes and as escape ways during the construction phase as well as for ventilation as soon as the line is operational. Contrary to tunnel construction, shaft construction is noticeable aboveground. The space needed for the set-up and operation of construction sites is difficult to find in an urban environment. Furthermore, such planning premisses as cost-efficiency, safeguarding environmental interests, and much more need to be considered.
Following their completion, these shafts are required to access and ventilate the system. Once everything is completed, the shafts are hardly noticeable, as they are covered and discreetly integrated into the cityscape.