The Puhoi-to-Warkworth Upgrade of the Northern Motorway (SH1) to a four-lane dual carriageway, runs from the Johnstone’s Hill tunnels to Warkworth, North of Auckland in New Zealand.

The project includes 18.5 kilometres of new highway and 12 bridge structures, including seven major viaducts.

BG&E provided the tender design of three long-span structures for the upgrade project.

The scope of works included concept options for a launched concrete box girder bridge and an innovative launched-haunched steel composite bridge with spans up to 70 metres.

Our team also worked in collaboration with the WSP-AECOM project team during option development. The bridges were designed to the comply with NZ Transport Agency’s Bridge Manual and in accordance with Australian and NZ Standards, and included carefully detailed construction sequencing and methodology.