Guyed masts are one of the most complex non-linear structures that one can encounter as a structural engineer. Due to the nature of the non-linearity of the cable elements, the solving of the cable forces is a highly iterative procedure. Appurtenances attached to the mast are generally modelled as applied dead and wind loads in the model, whilst thick feeder cabling can also effect the mast solidity ratio and add significant wind and dead load.
In 2012, the telecoms giant Sentech SOC, embarked on a countrywide network expansion project which included the upgrading of some 180 sites from the existing Analogue transmission to Digital Terrestrial Television (DTT).
The DTT works package are broken down into two main components:
The broadcaster transmitter stations are more often than not located on remote mountain tops or high ridges, in unmanned areas and are only visited on a scheduled maintenance or call-out basis. Some of the 4-leg “Liebherr” type masts that were considered for this project are in excess of 280m in height.
The addition of the new transmitter sites will ensure maximum digital terrestrial coverage in the far lying areas of South Africa.