Because on the other side they were hitting sheer rock after just half a metre. The first step was then to dig out the old foundation and reinforce it to ensure stability during the building works. The 50 m high new mobile phone tower also had to be custom made. “Generally our standard towers consist of three sections that are joined together with flange plates. In this case we produced a tower in four parts, so that it could be transported up the hill in the first place,” recalls Weiss.
Replacing the switch cabinet
Within a week the tower had been erected, the antennae mounted and aligned, the cable laid and the system technology connected in the switch cabinet next to the base of the tower. “That was the next challenge, because there was definitely no room for both the old and new switch cabinets up there,” explains Weiss. So the old switch cabinet was removed there and then by crane to a nearby forest path. The length of the cable allowed the old system to be reconnected to the network until the new one had been prepared.
Approval process and soil report
Swapping a tower requires a certain lead time. District offices or municipalities have to approve the building application, while departments like nature conservation authorities or water management bodies need to approve the tower location – and they sometimes impose additional requirements to be met. “At times we had to do a count of the lizard population, hang up bat boxes or renovate a playground,” Weiss recalls. If there is an airport in the vicinity, air traffic control gets involved. If necessary an aircraft warning light will have to be fitted to the top of the tower, i.e. in the form of a beacon or aircraft warning paint.
Following approval for construction the soil conditions are investigated. An expert soil surveyor will produce the soil profile and suggest a preferred type of foundation. Sometimes it is possible to work with just a driven casing pipe that goes several metres into the ground and has just a slightly larger diameter than the mobile phone tower itself. In other cases the foundation has to be reinforced, e.g. if the soil is sandy or peaty. This also depends on the specified tower height that was calculated for the area, which is generally between 10 and 60 metres. Our own Structural Analysis and Engineering Department calculates the most economic foundation based on the soil report and the structural analysis of the tower.