Project name: Historic Hāpuawhenua Viaduct Restoration
Project location: Tongariro National Park (North of Ohakune)
Timeframe: Completed 2008
Description of the project, and Frame’s role
The Hāpuawhenua Viaduct was completed in 1908 as part of the North Island main trunk railway and was one of five viaducts built between Ohakune and Erua, that was required to navigate the difficult terrain. Designed by engineer, Peter Seton Hay the 284m long curved steel truss railway viaduct stands approximately 43m above the valley. After many years of use a deviation was opened in 1987 which rendered the Hāpuawhenua Viaduct obsolete. The viaduct was mostly unused apart from a short time when it was used by AJ Hackett and a bungy jumping platform was constructed in 1988.
Frame Group worked alongside the Department of Conservation and Project Tongariro (Tongariro Natural History Society) to retore this piece of history for everyone to enjoy. As the viaduct is a Category 1 classification by Heritage New Zealand, special care and consideration was taken to maintain the heritage of this site.
The restoration included two stages:
Stage 1: Water-blasting the viaduct to remove volcanic ash deposits, lichen, and other vegetation to reduce the rate of future corrosion of the steelwork, and to enable a more thorough inspection of the extent of corrosion.
Stage 2: Installation of new joists, decking and barriers allow pedestrians and cyclists to experience the viaduct for themselves.