In transmission line towers, the tower legs are usually set in concrete which generally provides good protection to the steel. However defects and cracks in the concrete can allow water and salts to penetrate with subsequent corrosion and weakening of the leg. When ferrous materials oxidized to ferrous oxide (corrosion) its volume is obviously more than original ferrous material hence the chimney concrete will undergo strain resulting in formation of cracks.
The cracks open, draining the water in to chimney concrete enhancing the corrosion process resulting finally in spalling of chimney concrete. This form of corrosion of stub angle just above the muffing or within the muffing is verycommon insaline areas. If this is not attended at proper time, the tower maycollapse under abnormal climatic conditions. Maintenance and refurbishment of in service electric power transmission lines require accurate knowledge of components condition in order to develop cost effective programs to extend their useful life. Degradation of foundation concrete can be best assessed by excavation. This is the most rigorous method since it allows determination of the extent and type of corrosion attack, including possible involvement of microbial induced corrosion.
In this paper, Physical, Chemical and electro chemical parameters, studied on transmission line tower stubs excavated from inland and coastal areas have been presented. A methodology for rehabilitation of transmission tower stubs has been discussed.
Corrosion, Transmission lines, Galvanizing
