Otira Viaduct
Otira Viaduct | |
|---|---|
Otira Viaduct looking North, 2001 | |
| Coordinates | 42°53′10″S 171°33′19″E / 42.88611°S 171.55528°E |
| Carries | State Highway 73 (Otira highway) |
| Crosses | Ōtira River |
| Locale | Otira |
| Maintained by | New Zealand Transport Agency |
| Followed by | Wallace Point Bridge |
| Location | |
Interactive map of Otira Viaduct | |
The Otira Viaduct is a large road bridge to the south of Otira, between Otira and the Arthur's Pass summit. Completed in 1999 by McConnell Smith Pty Ltd, the 440 metres (1,440 ft) four-span viaduct carries State Highway 73 over a stretch of unstable land, replacing a narrow, winding, dangerous section of road that was prone to avalanches, slips and closures.[1][2] One person, Tony Western, 25, was killed during construction in July 1998 when a chain failed and a pump fell on him.[3] A plaque was installed in his memory in the base of the westernmost pier.
Description
The Otira Viaduct is a four span cantilever bridge with a length of 440 metres (1,440 ft) and average grade of 12% on its deck. Each pier is about 40 metres (130 ft) high, supported on excavated cylinders which are 4 metres (13 ft) in diameter and 30 metres (98 ft) deep.[4]
History
Old coach road
Construction of the Ōtira Gorge and Arthur's Pass road began in the winter of 1865 and, until completion of the Viaduct, was a dangerous section of highway. From the summit of Arthur's Pass to Otira, the highway descends 495 metres (1,624 ft) in the short distance between them.[5] The pass was constructed in 10 months and the original coach road was opened in March 1866. The construction was completed during a harsh winter for the pass, which receives an annual average rainfall of between 4,000 millimetres (160 in) and 7,000 millimetres (280 in), in addition to regular snow and minimum temperatures well below zero. Throughout the construction, many workers were drowned in flooding rivers. This included six workers drowning in the same week.
The former coach road included 11 bridges with a total length of 406.6 metres (1,334 ft) and five 360 degree bends through a dangerous zig-zag section.[6] Construction was carried out by contractors J. Smith and E.G. Wright using labourers with picks, shovels, wheelbarrows and two-horse drays. The road was constructed and designed under the authority of the Canterbury Provincial Council by engineers Edward Dobson, George Thornton, and Walter & Edwin Blake.
References
- ^ Ewen, Peter (2 November 2019). "Conquering the Otira : 20 years of the viaduct". Greymouth Star. pp. 6–8.
- ^ "Arthur's Pass – Otira Viaduct". arthurspass.com. Retrieved 26 April 2017.
- ^ Harvie, Will (6 November 2019). "Award-winning Otira Viaduct near Arthur's Pass notches up two decades". Stuff. Retrieved 9 January 2026.
- ^ "Otira Viaduct Bridge Construction". Numa Hammers and Bits. Retrieved 26 December 2025.
- ^ "Ōtira Gorge and Arthur's Pass road". Engineering New Zealand. Retrieved 25 December 2025.
- ^ Stace, F.N. (1990). Engineering to 1990 (PDF). Engineering Publications Co Ltd. p. 42. Retrieved 25 December 2025.