Bridges

The recently completed East Taupo Arterial project is a 16-kilometre section of new highway running along the eastern outskirts of Taupo, North Island, New Zealand. This new road is provided to reduce the number of heavy vehicles travelling through the Taupo CBD and along the lakefront and to reduce traffic congestion during the holiday season and events. This project, first proposed 40 years ago, features two large steel-composite bridge structures including a striking new bridge over the Waikato River. This bridge, with a 100m network arch central span, provides two lanes of traffic, a footpath/cycleway and provision for two large diameter steam pipes to be carried on the bridge deck. Currently this bridge is the largest and second only network arch bridge in New Zealand. This paper discusses the design and innovations in this network arch bridge. This includes the adoption of concrete filled steel box sections for the arch top chord members to cater for a critical design case where hanger bars may be struck by an errant vehicle. This paper also explores the challenges faced with the construction of the bridge over the Waikato River. There were a number of key stakeholders, including the local (Maori) iwi, the Department of Conservation and the various users of the river and its water, which governed the project methodology. A significant amount of temporary works was required to support this light weight and flexible structure as it was assembled over the river. The key factors in the successful completion of this iconic structure are discussed.