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Project: T183700 #3278
 

The condition of steel members in overhead transmission line (OHTL) towers is critical to the structural integrity of the system. Rust can develop in local areas and spread across the member, compromising its strength and establishing weak points. Failure of members due to rust damage is a serious risk and can lead to the structure failing, causing power outages and significant knock-on costs.

The objective of this report is to provide the methods and rationale that were used to inspect and assess the condition of steel tower members on four OHTLs in Iceland and five in Norway. The assessment methods are based on taking measurements of the galvanized layer on the steel member, thereby providing an indication of the condition of the steel towers and the basis for estimation of their remaining lifespan. Using such an assessment methodology, one can monitor the deterioration process and make effective decisions concerning further investigations and maintenance and repairs, if needed.

Included are directions for the recording of assessment results, the statistical interpretation of said results, and an explanation of how a change in condition over time can be used to maintain the integrity of the steel towers. Further, the report includes advice for tables and diagrams that may be used to evaluate the results of the measurements.

Keywords:

Steel Tower, Condition Assessment, Corrosion, Galvanization Measurements, Transmission Line Towers