“The motivation for the research was organisations like Transport and Main Roads, they want to basically know how their bridges are performing, so they tend to go out there and do visual inspections on bridges,” Dr Cowled said. “They have an expert go over it and if they pick up on any issues they can try to order rectification works and things like that to maintain them. “But sometimes a lot of unseen damage can go unnoticed, and what the structural health monitoring … approach to dealing with these things is to monitor a structure over a long period of time. “From the data you’re gathering directly from the structure, you can infer where damage might be located.” He said most research into monitoring bridge health was done on very simple models of bridges, but the eight-metre-long model he created was far more complicated.

The complexity and size of the model meant he could glean more precise information from the tests, concluding that to be completely accurate, the tests would need to be completed on a specific model of each real-world bridge. “What I was able to show was the complexity of the structure does, indeed, affect your ability to detect damage using vibration-based methods,” Dr Cowled said. “So many people had said this was the case, but no one had actually done … the numbers to see if that was true.” Dr Cowled's complicated bridge model. Credit:QUT The findings mean engineers could have a better understanding of each bridge’s safe limits and better identify when a bridge needs maintenance and repairs.

Dr Cowled had faced not just personal injury during his PhD research, but the closure of QUT’s structural monitoring lab the same year he enrolled. He spent a year off being a full-time parent until a new structural monitoring lab at Banyo was built and he could begin working. Then in 2013 he faced a major hurdle: cycling to work, he was hit by a car and suffered a serious hip injury, the bone eventually bolted back into one piece. Slowly recovering, Dr Cowled lived in constant pain for years as his wife Natalie encouraged him not to give up on his research. “It took me about three or four years to physically recover to a point where I’m not in pain all the time,” he said.

“I had a lot of desperate time in there, my grandfather passed away who I was really close to. “My wife, one of the things that I love about her is that even though she doesn’t understand what I do, she said to me, ‘listen, I believe you can do it’ and she insisted that I continue. “There are a number of times along that path where you just think 'wow, it’d be easier to just walk away and go back to designing buildings'.” Alongside his wife’s support, Dr Cowled said he’d been bolstered for years by the close support of his parents and his grandfather. His grandfather Les Ridgeway was an elder of the Maiangal clan of the Worimi nation.

Although Les finished his education at just 12 years old, he instilled in his grandson the importance of learning. "In higher education, broadly speaking, Indigenous people are underrepresented,” Dr Cowled said. “My grandfather … really really strongly believed in an education for Indigenous people. He saw that as the way of making something out of life. “He made sure with my mum and my uncle and my aunt that they all got a tertiary education. “For him it wasn’t even a question. It was ‘you are going to do this’. He saw the value in getting educated and how that can help lift people out of poverty and disadvantage.”

Dr Cowled said continuing his grandfather’s efforts to encourage more Indigeneous people into education, particularly science and engineering, was important. “I really do want to do what I can to encourage more Indigenous people into science and engineering because it’s rewarding,” he said. “The work you do in this space, in the technology area - you see the things that you design and build, people build them and it’s such a rewarding thing.” After his PhD attracted a host of compliments from examiners, Dr Cowled said he was looking forward to to fresh research – a new challenge after already overcoming so many. “The awesome thing about having finished a PhD is that I can focus now on research that I feel really deeply passionate about myself, and that’s going to make the next few years even more fun," he said.