Abstract
Accelerated corrosion of tens of thousands 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 or near the ground level is becoming a key risk to weathering steel structures (WS) 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/lattice structures will be discussed, considering specifically; corrosion risk at ground level and Pack-out, Finite Element Analysis (FEA) analysis, corrosion mitigation and repairs.
The case history portion of the paper will include actual case histories that involved both accelerated corrosion at the ground level due to coating degradation/delamination, pack-out formation and FEA analysis to determine the integrity of the joint.
