Almost 20 years ago the use of Ultra High Pressure Waterjetting (UHP) in shipyards for maintenance and for offshore projects started to be pushed, due to the development of surface and moisture tolerant paint technology becoming available. This was recognized by the likes of US Navy and Petrobras at the time. 

Accelerated corrosion of aging transmission structures in electric power transmission lines is a leading cause of in-service equipment degradation. Each year utility companies spend an increasing amount of their revenue on inspection and refurbishment of corroded structures and maintenance of the large population of aging structures has become a serious engineering and economic problem.As these assets age corrosion at the ground level is becoming a key risk to weathering steel structures as metal thickness loss leads to a reduction in structural strength potential asset failures reduced system reliability and costly repair or replacement. Preventative maintenance for steel structures has quickly become an important topic for engineers to consider both during design and in the field in order to reduce the costs of corrective maintenance many decades later.Accordingly effective and economically feasible corrosion mitigation techniques specifically designed for weathering steel transmission poles are in high demand.In this paper the principal corrosion mechanisms for weathering steel utility pole structures at and below the ground level will be discussed considering specifically; corrosion risk stress calculations FEA analysis corrosion mitigation and repairs.Coating and cathodic protection (CP) are the most effective methods for mitigating corrosion in aging transmission lines rovided that the designer considers the corrosivity of the environment the potential for and mechanisms of cathodic protection shielding characteristics for grounding and soil corrosivity. The potential to which the structure must be polarized also needs to be considered while taking into account the grounding and soil resistivity. This potential determines the degree to which the corrosion rate is reduced below grade.The case history portion of the paper will include actual projects that involved both accelerated corrosion at the ground level coating degradation coating selection and computer aided design for cathodic protection.Key Words: Weathering Steel Transmission Pole Ground-line Corrosion Protective Coatings Ground Sleeves Soil Corrosion Pack-out Corrosion Risk Assessment Cathodic Protection Welding Load Bearing Member FEA Analysis Transmission Structure Repair Protective Maintenance Corrective Maintenance

Thermal spray coatings (TSC) have been successfully used in all major sectors of the marine and industrial corrosion control coatings market.