Technical Review: Performance, Design, and Deployment of Steel Helical Pile Groups for Transmission Infrastructure

Worldwide transmission-grid expansion requires extensive construction of new tower foundations across diverse geological, environmental, and logistical conditions, while conventional bored piling faces increasing cost, schedule, constructability, and adaptability constraints. Steel helical pile groups have been proposed as an alternative, but a systematic evaluation of their suitability for Australian transmission infrastructure has been lacking. This narrative review synthesizes Australian and international case studies, current design standards, and published installation-productivity models to compare helical and bored piles on installation logistics, quality assurance, structural and lateral load performance, environmental footprint, and the under-examined implications of foundation type on tower earthing and lightning performance. The comparison finds that helical piles offer real-time, torque-based capacity verification, immediate load-bearing capacity, and lower labor intensity under favorable ground conditions. However, shallow competent bedrock, dense gravels or boulder-affected ground, and very high lateral-load structures favor bored piles or hybrid solutions, and helical-pile grounding performance for tower earthing has not yet been independently verified. These findings indicate that helical piles are a resilient, logistically efficient alternative to bored piles for much of Australia’s transmission foundation demand when applied on a site-specific basis, and the review recommends Australian design guidance and further grounding-performance research.