Modelling the Future

Sydney's Pyrmont Bridge 3D modellingThe Pyrmont Bridge in Sydney’s Darling Harbour is an ode to the city’s rich history.

Designed by Percy Alan and opened in 1902, the swing panel was – at the time – one of the world’s largest operating spans, opening to allow ships to enter Australian shores. The bridge accommodated some of Australia’s first cars, and was one of the first in the country’s history to be powered by electricity.

Fast-forward over a century, and while the Sydney skyline has changed remarkably, the bridge maintains its original architecture. The bridge’s owner Sydney Harbour Foreshore Authority (SHFA) had a tough task of working with a historic maintenance system, making the annual condition assessment of its over 8500 key structural points painstaking, lengthy, and expensive.

Since the former Darling Harbour Authority, now SHFA, took ownership of the bridge in 1984, Wayne Sahlman, Senior Facilities Supervisor, says a major challenge was a lack of documentation. Drawings were almost all paper-based, and had been lost as they changed hands several times over the past century.

“There was a lot of technical information that was archived, never to be found again,” he says. “There were scanned copies of some plans that were difficult to read. We sourced some documents from state archives, and the NSW department of Roads and Maritime Services had some drawings. In 2002 they undertook a major restoration of the bridge and had a lot of rendering, but we only got scanned copies – there were no AutoCAD drawings. Luckily we have the as-built asset – that’s the bridge itself. So although our documentation is building, as the end-user of these resources, you can imagine it’s quite frustrating.”

SHFA decided to be forward thinking by commissioning a full 3D model of the bridge. Although 3D modelling is quite common in the construction of new buildings, to undertake the task on an old building for maintenance purposes is a rather new approach.

“We had for long considered putting together a 3D model to reduce lifecycle costs. With the record keeping so poor, we needed a single repository of information,” he says. “It’s a complex structure with many elements, and given the size and complexity of the bridge, as we discussed different elements, we realised we needed a 3D model where we could simply say: ‘X marks the spot.’”

SHFA put a fixed price contract on the market, seeking an open-source 3D Building Information Modelling (BIM) of the bridge, exportable in IFC format, meaning it can be read by different software. Engineering firm GHD in Newcastle undertook the work in close consultation with SHFA.

Prior to the 3D model being in place, up until this year engineers had to undertake the annual condition assessment process via a manual, paper-based process. Essentially, the workers would head to the bridge with clipboards and digital cameras, and spend three to four weeks inspecting each of its 8500 parts by hand, writing down notes, and evaluating the parts based on a one to four scale, while also taking photos.

They would then take these notes back to the office, and spend up to three months compiling the information in various spreadsheets, linking through to images downloaded from the digital cameras.

As a last step, they would colour in schematics of the bridge in different colour highlighters to mark the condition of each part, and hand in the full report to SHFA and its engineer to review and evaluate what work needed to be done.

This year, however, those engineers headed out to the bridge with iPad minis in hand instead of clipboards, thanks to the use of a cloud-based 3D BIM software developed by Zuuse.

“What Zuuse has done is to take the 3D model of the bridge and used it to generate the condition assessment requests against the elements that are inspected,” explains Jason Lilienstein, CEO of Zuuse. “The inspectors can automatically input the information, and even compare it against the previous year’s information. They can take photos and then automatically sync all of the data with the 3D model.”

Instead of waiting for the inspectors to file the report, SHFA’s Mr. Sahlman can check in daily on how the inspection is going, and see the conditions reported to date.

Instead of taking months to compile the report, at the end of the inspection period the report can be immediately exported, as the software has been compiling the data throughout the inspection. The report can be searched to see which sections require immediate attention.

“The whole system makes the inspection nice and easy, the information goes straight into the database,” says Mr. Lilienstein. “The advantages for the client is that the information is instant, it saves time, money and labour, and it gives rolling information to help with the day to day facilities management.”

Mr. Lilienstein says that with all of these advantages, 3D BIM software is showing it has a strong role to play in the future of maintenance work.

“Traditionally, 3D BIM has been targeted at the design and construction phases of a project. It makes sense to use a 3D model to assist in the virtual design and build of an asset by allowing more streamlined co-ordination, visualisation and collaboration,” he says. “We can see potential savings of 15 – 25 per cent off various parts of a project resulting from this. There is no reason why similar benefits cannot flow to the asset owner during the operational phase.”

Zuuse is starting to see companies test this theory by using 3D modelling in major projects to help with facilities management, with the Pyrmont bridge a prime example. SHFA’s Mr. Sahlman says that he expects to recover the cost of the 3D model and software investment starting in Year 2 on condition assessment aspects and mechanical maintenance work, and Year 3 and 4 in restoration works.

These advantages have helped SHFA considerably to tackle the challenges that come with the maintenance of a century-old, heritage listed bridge.

“We need a lot of consultation with our heritage department before we can undertake even basic construction and maintenance,” says SHFA’s Mr. Sahlman.

Another challenge is that which comes with working with a wooden structure.

“Typical of any timber bridge, it’s an organic product. It has a life cycle different than a normal bridge,” he says. “It really requires inspection above and beyond a modern bridge.”

SHFA has adopted a Memorandum of Understanding (MOU) with the RMS to use their same policies and procedures in bridge maintenance, including the yearly conditional assessment.

The Pyrmont Bridge is still an operational bridge, as it needs to be opened for passing ships, while also accommodating pedestrians. Considering all these factors alongside the fact that the bridge sits in the middle of the city in the public eye, make it an important and challenging project.

Mr. Sahlman is looking forward to using this technology to roll-out to other aspects of the bridge maintenance. In addition to modelling the structural components, SHFA further obtained a model of the electrical and mechanical components. With the condition assessment considered a successful trial, Mr. Sahlman is now looking to use 3D modelling and the cloud-based software as a tool in preventative maintenance and also in work package development.

“The first step was to understand the condition of the bridge, now we want to use it for restoration works,” he says. “Our use of this software is really in its infancy, and as we look towards a five-year rolling project to restore parts of the bridge, this software will certainly come in handy.”

With the 3D model in place, Mr. Sahlman says they’ll better be able to tender for the works, in having an exact understanding of what work and material will be required.

“We’ll be able to say exactly how much paint and timber will be needed. It will be so much easier to define,” he says. “Contractors will have a much better understanding of the scope of work, and it will lower their risk in taking on any project.”

With the Pyrmont Bridge project such a success, Mr. Sahlman sees a lot of potential for the software in facilities management, and will next be looking to model a building.

“There is real potential with this software to better manage heritage-listed buildings,” he says. “This is the future of facilities management, it’s where it’s all going. We like to think that we’re ahead of the game.”

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