Concrete engineering experts have weighed in on the cracks in Tasmania’s Bridgewater Bridge that were found just before it opened mid-last year but which only became public knowledge recently.
Days before opening to traffic on 1 June 2025, a large crack was detected in one of the piers of the $786 million bridge and was fixed, documents showed, according to ABC News. The 1.28km four-lane concrete box girder bridge, constructed by McConnell Dowell, received the Australian Construction Achievement Award in August 2025.
The crack in the plinth at the top of pier one was described as a “non-minor defect” in the documents obtained by the ABC.
“According to a department report, the shear key of that particular pier was designed to prevent movement in all horizontal directions, but load capacity had been miscalculated during the bridge’s design phase.
“The State Growth Department said “non-minor defect” was a “contractual term” and that it did not pose any risk to road users, and the bridge was safe.”
The plinth connects to the shear key above it which supports the deck of the bridge. This helps to keep any movement of the bridge, such as by thermal expansion, under control.
The structure’s 1082 concrete segments were installed one by one using a balanced cantilever method, extending outward from each pier in a self-supporting sequence. Each segment was placed and bonded directly against the previous one to ensure a precise and continuous fit, according to epoxy specialists Megapoxy.
One expert consulted about the cracking was Professor Rebecca Gravina, a structural engineering professor at the University of Queensland, who explained that as the concrete cracked, the internal reinforcement of the bridge pier and the plinth were doing their work.
When the cracks opened up, the stresses were redistributed to the reinforcing steel, so the reinforcing steel was doing its job, she said, adding that were no concerns from a structural engineering point of view, or a physics point of view, that the structure was going to collapse. Professor Gravina’s comments were echoed by Associate Professor Colin Caprani, head of structural engineering at Monash University.
About the author
Desi Corbett
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Desi is the Editor of Concrete in Australia, at the helm since December 2013, and our weekly news writer since 2016. Focused on concrete and construction for more than 11 years, her expertise in this field forms part of a journalism career spanning three decades. To get in touch please email desi@corbettcomms.com