Old Noosa Road Bridge Replacement

Linking Gympie to Cooroy via Cooran, Old Noosa Road plays a vital role in the transport network of the Sunshine Coast Hinterland. Thanks to an investment by Noosa Shire Council and the Federal Government the region has benefitted with an upgrade to the timber bridge at Cooran as part of the Bridges Renewal Program.

Madsen Giersing and Casa were awarded a design and construct contract to replace the existing bridge with a new concrete bridge better suited to meeting the needs of users and withstand the environmental challenges of the site.

Our role was to undertake the detailed design of the new bridge and to offer construction support through to practical completion.

To simplify construction and to ensure that we were able to meet the requirements of the client, we focussed on the practical elements of the site and recommended an approach which focussed on constructability.

Senior Design Engineer, Dr Yasintha Bandula Heva, led the project for Madsen Giersing and to enable ease of construction broke the 35m length and 5.1m width of the bridge into three spans of 5.44m, 24.17m and 5.44m which allowed the use of pre-cast and stressed concrete panels to complete the spans. This approach removed works from the waterway which is a habitat for endangered frog species.

Spans 1 & 3 consisted of two 3.1m x 0.4m pre-cast panels and Span 2 comprised nine 25m deck units which provided the most efficient and cost-effective solution, which resulted in the project being delivered on time and to budget.

The newly designed and completed bridge also had to take into account the region’s high rainfall, increased traffic and modern safety requirements. Located close to the site proposed for the Traverston Dam, the area receives significant annual rainfall and like much of Queensland is prone to flooding with the old wooden bridge regularly becoming inundated, preventing use and creating a risk to users.

To overcome such challenges, the new bridge is designed to last for 100 years and to withstand a 1 in 2000 ARI flood event. With a load limit suitable for 44-tonne trucks and a new guard rail to improve protection for road users and pedestrians, the new bridge is an essential piece of modern infrastructure that is of significant benefit to the communities served by Old Noosa Road.