Pylon Network Upgrade

Client: Transpower

Location: Central Otago

Allied Concrete’s Alexandra plant led the charge on a recent pylon upgrade project for power transmission company Transpower. Taking place over two years, the project involved increasing the concrete foundations under each pylon leg to enable the pylon to carry the extra weight of another cable to carry power north from the Tiwai Point Aluminium Smelter near Invercargill. 

Leasing Ranfurly Transport’s concrete plant (and upgrading it to CNZ certification) and tolling some loads out of Kiwi Concrete in Oamaru, Allied Concrete delivered loads over the Danseys Pass to the Livingston substation in the Waitaki Valley.  

It was a mammoth effort, with 570 pylons upgraded across the 228-kilometre network. A total of 8253.2 m³ 25MPa concrete, with a 10kg dose of steel fibre per m³, was supplied for the project.  

Area Manager Gavin Magrath says the project was both interesting and demanding, especially with challenges accessing some of the pylon sites. The terrain was extremely mountainous in places with weather playing a major part due to altitude over the Danseys Pass. It can snow on the Pass at any time between March and October, and reaches temperatures exceeding the mid-30s in the summer months, he says. 

The expertise of Allied’s drivers was also key to the project’s success. Apart from just seven pylon sites that had concrete helicoptered to site, all other pylons were accessed by our trucks under their own power. An impressive feat given the mountain ranges reach more than 960m above sea level in some areas.  

Across the board there were zero medical treatment injuries (MTIs) and zero lost time injuries (LTIs), as well as no breakdowns with plant or fleet resulting in failure to deliver on any day. A great team effort from across multiple plants meant this project was delivered professionally and efficiently.