Replacement of two 320m masts in Sweden

Abstract

ABSTRACTThrough the recent three years Teracom in Sweden have replaced two 320m guyed masts to new masts that are designed by Ramboll. Whilst the old mast in both projects was built in the 1960s and primary served as support for FM/TV broadcasting antennas, the background for the replacement is significant different. One mast was exposed from a fatal sabotage, where it was succeeded to have the new mast in service less than one year from this date. The other mast is placed in an area that experience heavy ice formation on a yearly basis and has been replaced due to a lack of fatigue capacity.The new masts have been designed by a full dynamic model, accounting for the local climatic conditions in respect to wind, ice, guy rupture and including maintenance‐free tuned liquid sloshing dampers at the top. For the guy ropes separate foundations have been designed; either gravity based or anchored into the bed rock where applicable. The design has been optimized with respect to the use of materials and particularly in respect to logistics and site work.As the major roll‐out of this type of masts generally went on some years ago, this paper will present some of the issues when designing and building 300m masts to current standards, including some of the specific challenges on the two projects. Topics from installation will also be described. In both project the existing mast (or what was left of it) was kept in service while building the new at less than 20m distance