OVERVIEW: Galvanised Steel Transmission Towers were buried in soil, and the legs were experiencing metal loss and severe corrosion at the highly susceptible natural air/ground interface of the steel members.
The client needed help in strengthening the legs of the affected transmission towers and was looking for a solution that would last 50 years.
INDUSTRY
ENVIRONMENT
Atmospheric –buried low or high pH soil depending on location
SUBSTRATE
Galvanised Steel
CHALLENGE
Metal loss was detected on some legs of the transmission towers while other legs showed signs of severe corrosion at the highly susceptible natural air/ground interface of the steel members.
The client needed help in strengthening the legs of the affected transmission towers and was looking for a solution that would last 50 years. This was highlighted as a necessity for the towers that are in areas exposed to varying pH level soil & prone to poor water drainage and flooding.
SOLUTION
We recommended coating with RB 300, a glass-flake filled vinyl ester, which has excellent resistance to corrosive environments. It provides a tough impermeable barrier suitable for steel and concrete surfaces. This system, once applied, can prevent future corrosion on the steel legs of the transmission towers for the next 50 years.
SCOPE
Excavate and break out foundation, removal of earthing strap if required
Install wire rope sling on transverse face according to wind direction, rope tension – 3
.5kN, min SWL – 23kN
Remove tower bolts and clamp reinforced angle steel inside existing leg, match drilling process
Holes sprayed with Cold Gal & high tensile bolts used
Punched bolts so that nuts don’t come loose
Abrasive blast & apply RB 332 as per specification
K-brace strengthening
Polymer concrete independently tested and rated up to 65 MPa (NATA certification)
Non-shrink to prevent gap between concrete and steel surfaces
PRODUCTS
OUTCOME
The customer was most satisfied with the outcome. Chemcote has been awarded subsequent jobs due to the success of these repairs.
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