A Comprehensive Groundline Vulnerability Assessment Tool for Direct Embedded Steel Transmission Poles

Groundline integrity of aging direct embedded steel poles is the subject of this paper. Compromised direct embedded steel structures at the groundline are cause for thorough consideration regarding the potential for catastrophic structural failure and potentially the circuit. Three elements are considered in this assessment approach: 1.) structure design and loading conditions per code; 2.) structure condition-health; and 3.) structure capacity reduction. These elements represent a novel, holistic approach in assessing vulnerability and risk for embedded steel transmission structures, allowing for replacement prioritization, materials sourcing, labor allocation, and budget planning.Traditionally, the groundline assessment of embedded steel poles often relies on non-destructive testing to determine wall thickness degradation, then, percentage wall loss criteria are applied to determine structure replacement. Unfortunately, this specific replacement approach does not consider structural loading conditions, design parameters, environmental events, or conditions, nor the reduction of structure capacity due to wall loss.This paper focuses on the application of a comprehensive risk-based assessment solution for direct embedded transmission structures, addressing resiliency at the groundline. Groundline components are identified, and risk evaluation criteria and a ratings scale are then established. Structure design parameters are identified and evaluated for capacity reduction due to wall loss and loading conditions. Additionally, risk evaluation criteria and ratings scale are established.Output of the risk-based assessment solution yields risk scores for each structure regarding structural integrity at the groundline and is based on condition-health and capacity reduction, and a composite risk score that can be further established.Structures can be risk-ranked by score for consideration and prioritized for possible corrective action. This assessment solution supports economic considerations for utilities to repair or replace structures and/or circuits.