On the 15th of May 2016 the old 320 m guyed mast in Borås was exposed to sabotage and 200 m of the top of the mast fell down to the ground. Due to the collapse Teracom wanted a new mast designed, manufactured and installed as soon as possible.
Teracom is the main TV and Radio Broadcast provider in Sweden and operates more than 600 guyed masts and self-supporting towers.
The old guyed mast was from the 1960s. The mast was designed using circular tubes for both the legs and bracing members to reduce the wind load on the tower.
Ramboll was selected for the job to design the new mast with new foundations. At the same time as the design was carried out, prices were received from manufacturers of the mast, the guys, the foundation and the erection. Prior to the design Ramboll should together with Teracom prepare site specific design requirements, including an estimation of the wind and ice loads on the site.
In order to make the production and erection as fast and simple as possible, the mast was designed with the same elements all over the height.
Unfortunately the mast needed to be installed in the winter time. This created serious challenges for the erection company due to the weather. The main problem for the installation in the winter time was not only the ice in the mast, but also the low visibility so it was not possible to see from the ground to the top of the mast.
Due to the harsh weather conditions Teracom has a special requirement for all their tall guyed masts that there should be a house in the top of the mast, so riggers working near the top of the mast have a shelter to use when the climate quickly changes. Furthermore there is a hoist installed in all the tall guyed masts in Sweden.
In order to check the design towards the requirements for hoist and house etc. 3D models were made of the top of the mast as well as the bottom of the mast.