Whakawhirinaki: The Silverstream Pipe Bridge
Brian Perry Civil is proud to have been selected to construct the Whakawhirinaki Pipe Bridge for Wellington Water Limited. The project involves replacing the large diameter bulk water pipeline that crosses the Te Awa Kairangi / Hutt River and Wellington Fault in Upper Hutt. The bridge was gifted the name Whakawhirinaki by local iwi at a dawn ceremony earlier this year.
This is one of the region’s most critical water supply pipelines for the bulk water supply network, supplying all the water to Porirua City and North Wellington. In its current alignment it is seismically vulnerable, difficult to maintain, and severely affected by corrosion.
The works include 750m of new 1m diameter steel pipe across the river and through the Manor Park golf course. The new seismically resilient three-span pipe bridge across the river consists of a network arch at the central span and steel trusses at the end spans. It will be 212m long and 6m wide to allow for the bulk main as well as walking and cycleways.
This project demonstrates our innovative, outside-the-box thinking to deliver value for clients. Through our ECI involvement, BPC and our project partners proposed an alternative design that drastically reduced the overall weight of the structure and seismic demand. This delivered a significant cost saving for the client and also reduced the carbon output by 1,914t.
At the karakia and naming ceremony, Taranaki Whanui Chair Kura Moeahu said Whakawhirinaki means ‘to lean against something, trust in something, depend on or rely on’. “Whirinaki is also the original name of the region,” Kura said, “so by naming this bridge Whakawhirinaki we are saying we trust in it and rely on it given the huge responsibility it has to carry our region’s water through Hutt Valley and Waiwhetu to its final destination.”