Major projects reach major milestones

Monday, 16 September 2024

Significant milestones have been reached on two of the state’s most important transport infrastructure projects, as the Australian and South Australian governments deliver on election commitments south of Adelaide.

In a major benchmark for the $120 million Majors Road Interchange project, 18 South Australian-made girders have now been installed for the widening of the Majors Road bridge.

At the same time, a new interchange and realigned intersection of Aldinga Beach Road and Aldinga Road – a major piece of infrastructure in stage two of the Main South Road duplication from Aldinga to Sellicks Beach – is starting to take shape.

The interchange will see the Aldinga Beach Road and Aldinga Road junctions realigned, and an underpass built at the intersection of Main South Road with the newly realigned roads.

At Majors Road, the girders – ranging in length from 23 to 31 metres and each weighing between 8 and 14 tonnes – were installed over four night shifts using a 300-tonne crane.

They will allow the existing Majors Road bridge to be widened from the current two lanes to six lanes, including two through lanes and a dedicated right turn lane, onto the Southern Expressway, in each direction.

As well as increased bridge capacity, the Majors Road Interchange project will see the construction of new on and off-ramps for the Southern Expressway at Majors Road.

Majors Road is an important arterial road in the southern suburbs, carrying around 13,200 vehicles per day, and is anticipated to reach around 14,700 during peak times by 2036.

The Southern Expressway carries approximately 74,000 vehicles per day between Darlington and the Reynella interchange and supports economic activity in Adelaide’s southern commercial and industrial areas and facilitates tourist travel on the Fleurieu Peninsula.

The girders were constructed by local company Bowhill Engineering, using 100 per cent regional South Australian labour, including 13 apprentices that worked on the project.

Each girder was transported almost 150 kilometres after their fabrication in Bowhill to the Majors Road worksite.

Bowhill also fabricated the original 16 girders used in the initial Majors Road bridge construction.

The Majors Road Interchange project is jointly funded by the Australian and South Australian governments, which each contributed $60 million, and is expected to be completed at the end of 2025. It is supporting approximately 245 full-time-equivalent jobs per year over the construction period.

Meanwhile the Aldinga Interchange begins to take shape, with piling works now underway.

Piling is the construction of columns in the ground that will provide vertical and horizontal support to the underpass and bridge structure, creating a strong and stable foundation.

Above the 53 piles currently under construction, the new underpass will have twelve 40-tonne girders supporting a bridge deck 26 metres long and 27 metres wide. The bridge deck will also feature 62 architectural panels and 86 metres of anti-throw screens.

The first permanent new asphalt section on Main South Road between Hart Road and Old Coach Road on the western side of the underpass is now open to traffic. This section of roadway will later become the permanent northbound on and off ramps.

The underpass will be made up of 39,200 tonnes of asphalt to create 86,000 square metres of road pavement, with more than 15.5 linear kilometres of soil nails supporting the underpass walls.

Stage Two of the Main South Road duplication between Aldinga Beach Road and Sellicks Beach is being delivered as part of the $810.4 million Fleurieu Connections project, with the Australian Government contributing $221.6 million and South Australian Government contributing $588.8 million.

As well as the Aldinga Beach Road interchange, the duplication includes intersection upgrades at Hart and Colville roads, Norman and Rogers roads, Hahn and Cox roads, and Sellicks Beach Road plus installation of wide centre medians and wire rope barriers to improve safety by separating northbound and southbound traffic.

It also includes three U-turns to facilitate local access and a shared use path for pedestrians and cyclists along the western side of Main South Road, from Aldinga to Sellicks Beach.