Decoding Galvanized Steel Coating Failures in T&D Structures: Corrosion Sensors and GIS-Based Corrosion Forecasting (C2026-00280)

Anil Chikkam, Peyman Taheri, mehrooz zamanzadeh, Farzan Zolfaghari

Coating degradation in galvanized steel transmission and distribution (T&D) structures is a gradual but critical process that impacts the long-term reliability of utility infrastructure. While galvanized steel benefits from sacrificial zinc protection, this defense deteriorates over time through electrochemical and environmental mechanisms. A thorough understanding of these failure modes is essential for accurate condition assessment and proactive asset management.
This presentation outlines the multi-stage degradation of zinc coatings, focusing on corrosion of intermetallic layers (gamma, delta, zeta, eta) and formation of corrosion products such as zinc oxide, hydroxide, and carbonate. Aggressive environments—particularly chloride-rich or low-pH—accelerate layer breakdown, weaken barrier protection, and expose the steel substrate.
A featured case study demonstrates the integration of real-time corrosion monitoring sensors with electrochemical testing and failure morphology analysis to develop predictive coating life models based on zinc depletion. Geographic Information Systems (GIS) are used to correlate corrosion patterns with environmental corrosivity and maintenance history, enabling spatially informed prioritization of repairs.
Field data from utility companies highlight the practical value of this integrated approach in predicting coating failures, extending asset life, and reducing unplanned outages. This work equips corrosion engineers and asset managers with a robust framework for ensuring the continued performance of galvanized infrastructure.