Evaluation of the Condition of Tubular Lattice Pylons

The Swissgrid grid comprises around 1,000 tubular lattice pylons. These pylons can be recognised by their uprights, which are made of closed tubes with hydraulic connections. These tubular uprights are filled with concrete and are subject to internal corrosion phenomena. Corrosion causes significant reductions in thickness and then leads to the destruction of the element. Swissgrid is looking for service providers offering a non-destructive corrosion analysis method that can be applied in the field. The proposed analysis method must be able to detect internal (non-visible) corrosion phenomena affecting the pylon. As part of this selective tender, Swissgrid will select a maximum of 3 bidders (Phase 1) to carry out a test on 3 pylons. If the results of the tests are conclusive, these 3 selected companies will be invited to submit a tender to analyse additional pylons divided into 3 lots (Phase 2).