Innertkirchen – Mettlen 220 kV Transmission Line, Reinforcement of Foundations of Masts 87 and 91

Masts Nos. 87 and 91 of the 220 kV Innertkirchen – Mettlen overhead transmission line, erected or rebuilt in the early 1950s, are located in a landslide area. The lattice towers stand on four separate and individual foundations. The foundations are not connected. Displacement and shift of the individual foundations has been detected. Differential shifting vectors were measured for the individual foundations. The resulting tension in the lower section of the mast frame caused an impermissible overload of different parts of the mast frame.

As a temporary immediate measure each of the four legs of the two masts was anchored to protect against possible winter loads. The guy was secured by anchors.

Main Data

  • Mast 87 / TR 1490 (support mast)
  • Mast 91 / TR 1490 (guyed mast)


Swissgrid AG


IUB Engineering AG

Construction period


Construction costs

Approx. CHF 70,000

Scope of services

Work stages 32 - 53