Reimagining Foundation Design in the Electric Power Transmission Industry-Paper

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The paper argues that rapid expansion and modernization of electric transmission networks require more consistent, efficient foundation design practices. Existing guidance is fragmented across thousands of utilities, contributing to inconsistent methods, compounded safety factors, and potentially overdesigned foundations. At the same time, current practices may not adequately address changing climate loads, environmental hazards, or the need to build lines quickly.

The Deep Foundations Institute’s Electric Power Systems Foundations Committee documented industry practice in its 2024 report, <em>Design and Construction of Deep Foundations to Support Electric System Transmission Lines</em>. The report catalogs foundation types and best practices, and identifies gaps in design models, load combinations, reliability-based methods, performance limits, geotechnical investigations, construction specifications, and quality assurance. It highlights particular concerns involving model use beyond validated limits, outdated rules of thumb for embedded poles, and inadequate consideration of scour, liquefaction, landslides, and other environmental effects.

The committee’s findings have informed an ASCE manual of practice for overhead power line and substation foundations. The draft manual provides guidance on selecting foundation types, developing loads and geotechnical parameters, conducting site investigations, and designing and constructing a wide range of foundation systems. It also addresses reliability-based design and assessment of existing foundations for upgrades. Separate committee efforts are developing guidance on environmental load combinations and pile groups.

The paper concludes that comprehensive, shared guidance—alongside targeted research and testing—is essential to improve reliability and economy, reduce unnecessary conservatism, and support the expansion of transmission infrastructure needed to connect sustainable generation and adapt to changing conditions.

Keywords

electric transmission networks

foundation design

deep foundations

utility standards

reliability-based design

geotechnical investigations

load combinations

environmental hazards

ASCE manual of practice

transmission infrastructure