Engineering Work (eg road, bridge, sawmill, dam)
Often referred to as the new Hapuawhenua Viaduct, this bridge epitomises the three aims of engineering: function, economy and (above all) grace.
Completed in 1987, this 414 metre long viaduct is the major structure on the 10 kilometre Ohakune to Horopito deviation. The Hapuawhenua Viaduct was designed by Beca Carter Hollings & Ferner Limited and constructed by Fletcher Construction Company.
The Hapuawhenua Viaduct was built not only to improve alignment but also to eliminate concern over the remaining fatigue life of the existing original North Island Main Trunk (NIMT) curved viaduct. Constructed from a combination of reinforced and prestressed concrete, this slender structure is a ‘state of the art’ design, which takes advantage of the development of engineering knowledge of the behaviour of structures under extreme conditions, and especially those of a major earthquake.
The viaduct formed part of the long deferred NIMT line electrification scheme, which enabled a 50 per cent increase in train load and cut the transit time by 1.5 hours. The NIMT track upgrading and 25 kilovolt alternating current electrification of the mountainous central section between Palmerston North and Te Rapa (north of Hamilton) is by far the most significant and far reaching improvement to New Zealand’s railway network since the completion of the NIMT in 1908.
This place is part of a Heritage New Zealand Historic Area (List no. 7793):
North Island Main Trunk (NIMT) Historic Area: New Zealand Heritage List/Rarangi Korero information (www.heritage.org.nz).
IPENZ “Engineering to 1990” project
This item of New Zealand’s engineering heritage was recognised as part of the IPENZ “Engineering to 1990” project which the Institution organised to help celebrate the country’s sesquicentenary in 1990. A plaque was unveiled to mark the significance of this railway viaduct as part of the development of the nation.
2 kilometres north of Ohakune on the North Island Main Trunk railway
King Country / Central Volcanic Plateau
This structure is not directly accessible because it is part of an operational railway. However, the viaduct can be viewed at close range from the surrounding Department of Conservation walking tracks: Ohakune Old Coach Road (www.doc.govt.nz)
Nature of Engineering
Rail Transportation, Building and Construction
Lat: -39.384998457436296 Long: 175.39960384368896