Aug 08, 2018

Mission to bridge key infrastructure disciplines

Mission to bridge key infrastructure disciplines

The structures team at the Australian Road Research Board is on a mission to change the way transport infrastructure assets are managed.

Their priority for the next few years will centre on bringing the disciplines of structural engineering and asset management together for a better outcome, according to team leader Tim Heldt.

Mr Heldt is the chief technology leader, future transport infrastructure, at ARRB and believes this is an area where the team can get the most value from its work around bridges.

“We often focus on the design and construction of new structures,” Mr Heldt said.

ARRB chief technology leader, future transport infrastructure Tim Heldt.

“But if you look at the asset portfolio, probably 90 per cent of the money has been spent.

“We have already built a whole bunch of bridges – so the question becomes, now that we’ve spent that money, how do we get the best value out of it? How do we provide the best service with it as opposed to saying let’s just build some more bridges.

“From a community point of view, I think there’s a lot of value to be had in trying to do this more effectively.”

Decision-making under scrutiny

Mr Heldt said making good decisions on the repair and maintenance of bridges was often hampered by a lack of data and the fact that condition assessments were not as reliable as people supposed.

It was possible to gather more data and pursue more intensive monitoring of bridges, including through new technology – but this would cost more money and may not necessarily bring better outcomes, he said.

“Let’s make sure that the simple data we have now is being used more effectively and that will help identify the areas where we really need more data and we can allocate resources to get that targeted,” Mr Heldt said.

It was important to make better decisions with the same imperfect data and a key to this was gaining a better understanding of the decision to be made and not making it in isolation, he said.

A fundamental principle of asset management was to understand that the focus was not so much the asset as the service it provided, Mr Heldt said.

“So if you have a bridge in a poor state, the question is do we need to fix it now? Who uses it and what service is it providing?

“If it’s the only route to local saleyards, you have to do something about it. But if this is a bridge providing access to a number of rural properties and occasionally a truck uses it but there’s an alternate route that means an extra 20km trip, then you might say ‘we can’t get to that for some time’ and you might put a load limit on it.

“You are still providing a service for most users and there’s an alternative with a slightly higher economic cost.

“It’s about taking a step back. There may be a bridge that needs repair, but the real question is who is using it and what are they using it for? The asset is a conduit to provide the service. It’s not the end game. Particularly in the structural space, that is something we need to think more about.”

Asset management was about getting the balance right, Mr Heldt said.

Bridge condition assessments uncertain

One problem was people’s faith in condition ratings based on visual monitoring, he said.

Mr Heldt points to a Federal Highway Administration study in the United States in 2001 that showed that more than 50 per cent of the average bridge condition ratings were not accurate.

“The point is that condition assessment is an input to a decision, but it is very uncertain so don’t place too much emphasis on it,” he said.

“Structural engineers say ‘you give me the info and I can calculate capacity’ – but an Austroads research reports shows you will get a range of answers from different people – so even when we do all our calculations it’s a guide, it’s not precise – it’s an input.

“So you can spend bucketloads of money on this and actually not get a much better answer.”

Another issue to be addressed was the way people viewed risk when it came to bridge condition, he said.

“As engineers we look at likelihood, we look at consequences, bundle it up into numbers and try to make decisions based on that,” he said.

“If we go to court, the courts don’t look at it that way – so there’s a need to change the way we look at and manage risk as part of the whole exercise.

“Effective record keeping is a key issue, including for the legal process, and that’s a big challenge – particularly in a large, complex organisation where people typically retain a lot in their head and so on.”

Mr Heldt believes that while the industry is starting to draw on asset management principles and doing a better job of collecting data, there is a need to focus more on decisions – including the way they are reached and the way they are documented.

“My passion for the next five years is going to be taking the asset management principles – which arguably have only consolidated in recent years into an accepted body of knowledge – along with some of the disruptive technologies emerging around data, putting that together with structural engineering and saying ‘hey we can get a better result by putting all that together’,” he said.

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