The Mount Henry Bridge carries the

Kwinana Freeway The Kwinana Freeway is a freeway in and beyond the southern suburbs of Perth, Western Australia, linking central Perth with Mandurah to the south. It is the central section of State Route 2, which continues north as Mitchell Freeway to Cl ...

and

Mandurah railway line The Mandurah line is a commuter railway and service on the Transperth network in Western Australia that runs from Perth south to the state's second largest city Mandurah. The service is operated by Transperth Train Operations, a division of the ...

over the

Canning River The Canning River (Djarlgarra in Nyungar) is a major tributary of the Swan River in the South West Land Division of Western Australia. It is home to much wildlife including dolphins, pelicans, swans and many other bird species. Source a ...

Perth Perth is the capital and largest city of the Australian state of Western Australia. It is the fourth most populous city in Australia and Oceania, with a population of 2.1 million (80% of the state) living in Greater Perth in 2020. Perth is ...

, approximately south of the Perth central business district. At long, it is the longest road bridge in

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

. It spans the river between the

Mount Henry Peninsula Mount Henry Peninsula is a land feature and reserve located south of Perth, Western Australia, on the north bank of the Canning River near the Mount Henry Bridge in Salter Point, Western Australia. It covers , and includes both ''Banksia atte ...

and the suburb of Brentwood.

History

The bridge was constructed as part of the extension of the Kwinana Freeway carried out in the late 1970s and early 1980s. The bridge was opened in 1982. The construction contractor was

Clough Clough ( ; ) is a village and townland in County Down, Northern Ireland. It sits about 3 miles from Dundrum, County Down, Dundrum on the A2 road (Northern Ireland), A2 between Newcastle, County Down, Newcastle and Belfast. The A2 road (Northern ...

, and the project manager for Main Roads WA was Geoff Smith. Between 2004 and 2006, the Mount Henry Bridge was widened and strengthened to accommodate the tracks of the Perth Southern Suburbs Railway. The widening was carried out by adding an independent structure, which overlaps the original bridge.

Structural details

The original bridge is of post-tensioned concrete. It has nine spans with a total length of . The deck width is . In cross section it is a double box-section, with the upper deck (including

cantilever A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a canti ...

s) carrying traffic, and cantilevers at the bottom of the box carrying shared pedestrian and bicycle paths. The bridge was constructed segmentally, using a balanced cantilever construction method. The original bridge carried three lanes of traffic in each direction, with two shared pedestrian and bicycle paths on cantilevers at the lower level.

Widening and strengthening

To accommodate the new Southern Suburbs Railway (now the

), the bridge was widened and strengthened between 2004 and 2006. Under the new arrangement, the original bridge carries three southbound traffic lanes and the two railway tracks. The new structure carries the three northbound traffic lanes. Because of the aesthetic requirements, load limitations and limited site space at the approaches, the new bridge overlaps the original in cross section. The upper east side cantilever sits above the upper west side cantilever of the original structure, giving a total effective deck width of . The foundations of the new bridge are independent of the original, with each pier comprising two columns tapering from bottom to top. The new bridge was constructed by incremental launching. Contractors were Leighton Constructions. The design team comprised Wyche Consultants, GHD and Coffey Geosciences.

References

External links

* {{Australian railway bridges, state=autocollapse Landmarks in Perth, Western Australia Road bridges in Perth, Western Australia Railway bridges in Perth, Western Australia Bridges completed in 1982 1982 establishments in Australia