Out of the ashes: How a rural council’s project team saved a doomed bridge

By intouch posted 30 May 2018 18:02

  

If the success of a project is measured in terms of cost and time, Horsham’s Anzac Centenary Pedestrian Bridge could be considered a failure.

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But, to do so would ignore the skill and tenacity of the council’s project team, who overcame poor engineering advice, major design challenges, inaccurate cost estimates, wet weather delays and contractor liquidation to bring the project back from the brink and deliver an award-winning result for their community.

Since opening in September 17, the 80 metre-long suspension bridge that spans the Wimmera River has become a popular way for people to access the riverfront.

Jessica Leslie, Horsham Rural City Council’s Design Engineer and Project Officer, says the Wimmera River Improvement Committee had been lobbying for a bridge over the river for a number of years.

“We just have one vehicle and pedestrian bridge combined on the main highway that runs through town. The Anzac Centenary Pedestrian Bridge is the only other footbridge over the river, which is a really popular recreational area. There’s walking tracks and playgrounds, picnic areas and barbecues. The bridge was built to allow the community to utilise the river better,” she says.

“Through that group lobbying, the council came up with a few different concepts and then secured funding and went out to tender for a design and construct contract.”

That’s when the trouble began.

A long road

Anzac_Centenary_Pedestrian_Bridge_04small_.jpgDespite a rigorous tender process, Jessica says the project was plagued by problems almost as soon as the contract was awarded.

“The design and construct contract was awarded to a group from Wangaratta – that's pretty much when the problems started,” she says.

“This company had recently successfully completed a similar suspension bridge over the Cudgegong River in Mudgee.

“The council had GHD acting as a peer review from an engineering perspective, as part of the due diligence and the desire to not have a bridge that vibrated too much underfoot traffic. GHD highlighted some issues with the design and the design engineer that the contractor had employed.”

The project was delayed by 14 months as analysis packages went back and forth, the council’s staff turned over, the contractor's engineer failed to meet the requirements of the design standards and ultimately a new engineering firm, was brought on board to complete the design.

The design documents were then finalised, allowing construction to commence on site some 12 months later than originally planned.

Construction on site commenced at a similar rate to the design review and approval process; slowly, and with many issues.

“The contractor’s inexperienced site managers were provided with little support from their supervisors, leading to many construction processes needing to be repeated. Wet weather, muddy site conditions and flowing groundwater hampered the progress of piling and pile cap construction,” Jessica says.

“We had to re-drill the piles two or three times, because the fast-flowing groundwater kept sucking all the water out of the concrete. We'd drill it back up and the concrete would just look like crushed rock; it would be bone dry. So, we had to get the shaft lined with concrete then redo it.”

Then, as offsite fabrication commented, it became obvious that the contractor was having cash-flow issues.

There were requests for upfront payments to procure the steel required for the bridge, and rumours of late or non-payments to local subcontractors emerged and works onsite ground to a halt as local subcontractors refused to work, for fear of non-payment.

“You'd hear about it all through town and people caught wind of that. It's a small town, so then no other subcontractors wanted to work for them, either,” Jessica explains.

“Everything was grinding to a halt because there were works that we'd already paid them to do, but they weren't getting done.”

The contractors installed the footings, the towers went up, they got the main cables over, and they hung the primary deck beams with the vertical cables.

The next Monday, they went into administration.

Jessica says the council needed to do some fast talking to make sure they didn’t lose materials they’d already paid for.

“They were still kind of part way through fabricating, so there was a risk there that once liquidators came in they just sell everything in the yard, even though we'd already paid for a lot of the steelwork. My directors had to make a lot of phone calls,” she says.

50% complete, 100% challenging

Anzac_Centenary_Pedestrian_Bridge_10.jpgNow, the project team was left with a half-finished bridge – and a multitude of issues.

“Nothing was straightforward,” Jessica says bluntly.

The council took possession of the bridge in June 2016, and staff that had previously been overseeing the bridge became construction managers, organising everything from staff training, OH&S procedures, procurement, drafting steelwork shop drawings inhouse and determining construction methodologies.

“Once the contractor went broke we were naturally the people that stepped in to complete the construction,” Jessica says.

Of greatest concern was a ‘slack’ cable, created by differential tensions in the main suspension cables which caused the desk structure to twist. It was critical to resolve this issue before works could progress much further.

Without any length adjustment mechanisms built into the cables, the team had to develop an innovative solution to adjust the cable, while still supporting 10 tonnes of steelwork 3 metres above the river level.  

“We collaborated with the engineer and another bridge builder to come up with a customised clamp method which enabled us to pull the load from the taut cable into the slack cable, then release the taut cable to equalise the tensions – we found it was actually a few twists in the cable that were causing all the issues. Once the cable had been untwisted, all the flow on issues resolved themselves which was a huge relief,” Jessica says.  

As the team kept going, they kept finding more problems.

“Probably only 30% of the bolts were actually in, so then we put our staff members and myself through our working in heights training, so we could actually go out there and put all the rest of the bolts in the bridge,” Jessica explains.

“We didn’t have a construction methodology from the contractor either, so we needed to figure out the sequence of works for ourselves too. This can be quite complex with a suspension bridge because all the load needs to be on the main cables before the final calibrations can be complete – but we couldn’t calibrate the bridge with all the steelwork installed due to access issues.

“Some of the steelwork that had been fabricated didn't actually fit, so we had to come up with different types of movement joints for a number of various components. The bridge deck beams were sitting 250mm higher than their connection points at the towers, so we needed to come up with a way to adjust the heights while the beams were still suspended.

“Even things down to the decking material – there was no way of screwing it to the bridge. Even the suppliers didn't have a recommendation for us.”  

Meanwhile, the community was making its impatience known.

“Community angst regarding the slow progress of the bridge construction had elevated significantly, understandably so on a high profile project. We needed to demonstrate that works were continuing, and quickly,” Jessica says.

Despite the laundry list of complications, the council’s project team completed the bridge within four months of taking over. 

Out of the ashes

Anzac_Centenary_Pedestrian_Bridge_05smaller.jpgIn the end, the bridge and ancillary works came in at $1.5 million, $300,000 over budget, and 21 months behind schedule. 

However, Jessica says that through the need to innovate and build skills internally, the council now has a team that is ready to handle whatever is thrown at them.

“We now have staff that can maintain the bridge. It's an asset that we're going to have for the next hundred years, so it makes sense to have our teams skilled up, and give them knowledge of the structure so that they can maintain it and adjust it as needed, rather than having all that knowledge with an external contractor or consultant,” Jessica says.

Once the council took over the bridge construction, they used social media to win over the community by promoting local businesses involved in the project.

“We took a pretty proactive approach. They'd obviously seen works going very slowly with the contractor and once the contractor went broke, there was a lot of community uproar and comments on Facebook like, ‘You should have gone with a local,’ even though there are no local suspension bridge builders in Horsham,” Jessica says.

“But we took that feedback on board and promoted quite heavily the works that were happening at each stage and who we were using locally. We put photos on our Facebook page once or twice a week of what had been happening onsite and who had been doing it, and we got a lot of positive feedback on that.

“Usually on those Facebook posts you get a lot of negative feedback, but there was a lot of, ‘Can't wait. Looking forward to seeing this finished,’ or ‘Good on you for acknowledging these people.’ That was great.”

The Anzac Centenary Pedestrian Bridge was awarded at the IPWEA Vic Engineering Excellence Award 2018, sponsored by Ventia, for Excellence in Public Works Projects under $2 million, cementing its status as a true feat of innovation and endurance.

“It was lovely to get the award and be recognised for all the work that everyone put in. It was fantastic to celebrate with some of our consultants. We had two of our consultants and one of our contractors and the representative from the Wimmera River Improvement Committee that had lobbied for the bridge for years. They were all at the IPWEA dinner and it was a great chance to celebrate with them,” Jessica says.

“From the ashes of failure and negativity, this project shows that engineering innovation, the practical skills of public works staff and a lot of teamwork could rise to meet the challenges of the project. The final complete delivery of this engineering feat is an asset that the whole town of Horsham can be proud of and enjoy.”

What can other councils learn from the project?  

Anzac_Centenary_Pedestrian_Bridge_02smaller.jpgComing from a previous life as a senior structural engineer with a tier one high-rise design firm, Jessica says she was able to bring vital know-how and skills to the team, which made bringing the construction management inhouse feasible.

“Get the people with the right skills in the right positions; it's great to give everyone a go at different areas, but you need to have at least someone who has the correct skills to be overseeing that area,” she explains.  

The project review also revealed that it pays to look at different procurement options.

“When there's a project that we want to have a very close level of detail and control over, then probably design and construct may not be the way to go; we could have got the design where we wanted it and then gone for construct-only contract. But then you always get efficiencies out of design and construct that you don't get out of construct-only,” Jessica explains.

“So, there is a middle ground, but perhaps if we had put a little bit more of a clear definition around what the design process should look like and expectations of the quality of the work and all those kind of things, I think that would have changed the outcomes for this project.”

Finally, Jessica recommends doing a thorough investigation not just of consulting firms, but the engineers they employ, to ensure they have the right skills for the job.
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