Bridges

High Mast Lighting (HML) Columns along Victoria’s Eastern Freeway, constructed in the 1970s, are approaching the end of their design life.

Routine inspections identified cracking at the mortar pad mitres near the baseplate connection, prompting concerns about the fatigue resistance of the steel components – including the column shaft and anchor bolts. This was particularly relevant given the absence of modern fatigue standards at the time of construction and historical fatigue failures of similar structures elsewhere in Victoria.

This paper presents the investigation into the fatigue performance of the steel components of 21 HML columns, including detailed inspection, material testing, structural analysis, and fatigue assessment. Wind-induced cyclic stresses were identified as the critical fatigue mechanism. Based on the results, a targeted remedial strategy and ongoing monitoring approach were developed to manage long-term performance.