A portion of the Upper Daradgee Road (north of Innisfail) was very close to a bend in the North Johnstone River and a recent flood event had undermined the road. Tourists were also in the habit of stopping at this point in the road to look for crocodiles which posed a safety risk to passing traffic and tour operators. As the road was an important link for surrounding banana and sugar cane farms, further damage to the road would have isolated a large portion of the farming community. The Cassowary Coast Regional Council (CCRC) had successfully applied for funding to address this problem and had resolved to realign this section of the road.
As the realignment required the resumption of productive farmland, CCRC approached GenEng solutions to provide impartial advice in consideration of engineering reports and surveys to inform the geometry of the new alignment.
GenEng provided feedback on these reports and delivered a concept design to inform Council’s land resumption requirements. Council accepted our recommendations and proceeded with the land resumption while we produced the detailed designs for the road, drainage, water main and cane rail crossing.
Challenges
A key problem to solve was integrating a cane rail crossing into the road realignment design as the existing crossing was now to be situated on a super-elevated curve at a sharp angle to the road. This had the potential to create visibility and safety issues, and it was important for us to address this at the design stage. This required close liaison with the local sugar mill to understand their cane cutting practices and safety issues around the cane rail to determine correct positioning of signage and pavement markings to maximise visibility on this section of the Upper Daradgee Road. The design also needed to take into consideration the grading of the new rail crossing to match the elevation of the road. We wrote into our recommendations a process of Road Safety Reviews in ensuing cane cutting seasons to ensure crossing safety outcomes were achieved as intended.
During construction the region experienced over 2 metres of rainfall which resulted in a very frequent inundation of the subgrade of the road. We made our engineers available (both remotely and on site) to provide design advice to Council’s construction team and implement a working platform drainage layer design using a rock base to form the foundation of the road allowing a firm surface to work on.
Outcome
The construction of the Upper Daradgee Road was successfully completed to design specifications and the visibility of the rail crossing is operating satisfactorily.