The Darlington Bridge upgrade project was a $620 million development planned to protect the bridge from corrosion and degradation. The project marked an important stage in the delivery of Adelaide’s North-South corridor and will add on an extra (approximately) 3.3km to the existing Main South Road.
In this Australian and State Government funded project, McElligotts is proud to have been contracted to install protective coating across selected surfaces and structures. In alignment with our values here at McElligotts, the project focused on using Australian approved and manufactured components.
Roads and bridges are constantly exposed to the harsh elements and vibrations from vehicle movements and therefore are threatened by corrosion and degradation. Repairing a bridge from corrosion can be incredibly expensive, up to billions of dollars, so it is important to appropriately protect the structure from the elements. One of the two main ways to protect a bridge from corrosion is to isolate the structure from the environment with a protective coating. For this project, we were responsible for applying the protective corrosion resistant coating to the steel box girders present on three of the eight bridges. Each of the 22 bridge girders, weighing 1300 tonnes in total, were abrasive blasted to Class Sa21/2 which produces an even textured surface, making it easier for the coating to adhere. After this, the girders were primed and had two layers of top coat applied to complete the job.
The Challenge:
Of course, no project is complete without some material and weather challenges. As the bridge was not yet constructed, it made sense to have painting conducted on beams before they were erected. Therefore, each girdle was delivered to our facility to be profiled, primed and coated, which meant that lack of space was a challenge we had to overcome. We also found the large sections of the girdles made it challenging to maintain a ‘wet edge’, which meant we continually had to adjust our materials to extend the drying time of each coating layer. In addition, the length of the project meant that some of the coating work took place during the Tasmanian winter, a less than ideal climate for applying coating. In order to meet deadlines, we had to adjust our work schedule to reduce the amount of heating required to apply the paint.
Overall, the Darlington Bridge Painting project was a challenging, yet rewarding job that tested our skills and gave us the opportunity to problem solve. The project also saw us work with some of the largest components we have ever worked with which was pretty exciting.