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Landmark achievements on IPA’s 2016 Project of the Year

Sydney's stunning new waterfront attraction – Barangaroo Reserve – required some innovative thinking to overcome many of the unique engineering challenges during its construction.

Sydney's stunning new waterfront attraction – Barangaroo Reserve – required some innovative thinking to overcome many of the unique engineering challenges during its construction.Infrastructure Partnerships Australia’s (IPA) annual National Infrastructure Awards recognise outstanding individuals and projects making headlines in Australia.

One category in the prestigious awards is Project of the Year. Past winners include Brisbane’s Legacy Way tunnel, Regional Rail Link, the Melbourne Channel Deepening Project and other major rail, transport and construction projects. This year’s, however, bucked the trend.

Barangaroo Reserve, the stunning new parkland on Sydney’s harbourside, was crowned the country’s best infrastructure project at the 2016 IPA awards in April.

The project was recognised as a landmark achievement: an undertaking that combined building, marine, bridge and landscape design to arrive at an impressive, multi-use destination and public reserve.

Kieron Little, Lendlease Engineering Project Director for the construction of Barangaroo Reserve, talks to Roads & Civil Works Magazine about the major challenges and innovations involved in the creation of IPA’s 2016 Project of the Year.

The idea to redevelop the space, located at a prime spot on Sydney Harbour, was a long time coming. The Barangaroo headland was used previously as a car terminal and was once a thriving port consisting of a very flat asphalt deck.

The New South Wales Government wanted to revitalise the area, restore the headland to its natural setting and make it suitable for public use.

The state government established the Barangaroo Delivery Authority (BDA) to manage the overall redevelopment of the area, including the reserve. The BDA contracted Lendlease Engineering to undertake the project. A range of different firms, including Aurecon, WMK, JPW and Warren Smith & Partners were engaged by Lendlease and became integral contributors to the project’s many complex elements.

Logistical challenges

The design brief for Barangaroo Reserve outlined a number of significant challenges, including the construction of a subterranean cultural space, the quarrying and repurposing of 40,000 cubic metres of sandstone and strict environmental restraints. As Mr. Little asserts, the entire fabric of the 7.5-hectare site would have to change exponentially.

“This project had many elements in engineering contexts that are very rare. Many of the engineering components on the entire project were quite bespoke,” he says. Many projects would involve one or two unique engineering hurdles, but Barangaroo Reserve had them in abundance.

All of these challenges had to be contained on a relatively small site and, as Mr. Little explains, everything had to be precise and coordinated within this high-risk environment. “You’d have one tricky element that hadn’t been done before and it interfaced with another tricky element. It all had to come together as one at the end, as no one area could be completed until the other one was done in parallel,” he says. “The logistics of managing construction movement for over two years within the site to schedule and be on time meant there wasn’t much room for error.”

One of the main issues was that many of these different bespoke components had never been done before, let alone on one project. “We would go from meeting to meeting in the early phase and talk about these significant construction innovations. We had to do a lot of work to come up with the best options and to figure out the best people and team for the job. They had to have the right skill set to rise to the challenges,” says Mr. Little.

With few or no other projects to learn from, the team drew on a combination of individual expertise and experience to inform the planning and construction decisions throughout the project.

Big first steps

The first construction activities commenced in 2012, even as the planning process continued.

“We were still designing when we started construction,” states Mr. Little. “The longest task was the sandstone quarrying and excavation. We appreciated that it was going to represent a significant portion of our program so it had to start straight away.”

More than 40,000 cubic metres of sandstone needed to be quarried on site, transformed into 6600 blocks that weighed as much as 15 tonnes each and placed on the new 1.4-kilometre foreshore of the reserve. Once quarrying was complete, part of the site would be transformed into the proposed subterranean cultural space. “That large scale quarrying activity is quite rare – the quarrying, reclaiming the sandstone and the process to reuse it in the foundations is something that I’m not aware of happening anywhere else before,” says Mr. Little.

The excavation process had to be very precise. A notable fault line running through the area had to be identified, requiring exact measurements. Mr. Little says that old excavation techniques were used to identify the fault line and other cracks in the sandstone, and subsequently, finding the cracks and lines in the rock by hand became a crucial part of the process. “We were bringing together the old and the new,” explains Mr. Little. “Using those methods resulted in a fantastic sandstone yield.”

Fifty-tonne, triple-bladed excavators undertook the major legwork, helping to extract the material. As the sandstone was being quarried, the project team was still figuring out how to place the thousands of blocks in the park. “There were a lot of balls in the air at the early phase, but we knew the longer we put into planning and design, the better the outcome,” he says.

Another major logistical challenge for Mr. Little and the project team was placing the sandstone blocks in and on the foreshore. “It was a huge marine activity in one of the busiest traffic channels in Sydney Harbour. We were working next to a cruise ship terminal for the first nine months. We also had to work within the environmental restraints around when and where we could dig in the harbour,” he says.

A large portion of the base blocks had to be fully or partially submerged along the foreshore. “The challenge of putting large pieces of sandstone under water involved working with divers in a tidal environment. It was a high-risk activity, which involved using large marine equipment, designing specific block handling equipment and training our workforce to use it. The result was the successful placement of 6600 large sandstone blocks up to three metres under Sydney Harbour safely and to a tolerance of 20 millimetres,” he says.

Mr. Little says the typical approach would be to use a crane with slings to lower the blocks into the water, which could then be placed manually by divers. The magnitude of the project made this time consuming.

The solution was to use a block handler, designed by the project team, which used an excavator arm with horizontal and vertical sliders that allowed for precise placement of the blocks.

Creating the ‘Cutaway’

The site from which the sandstone was excavated was designed to become a subterranean cultural space with 18-metre walls and two levels of car parking below. The concept plan for the space, dubbed the ‘Cutaway’, included four rows of pillars with 10-metre spans to hold the roof.

However, as Mr. Little explains, the decision to introduce bridge technology for roof construction opened up usable space and provided greater flexibility for end use.

Members of the project team had been involved with a separate bridge project that had used precast Super Ts. While a typical component for bridge construction, it isn’t normally thought of for roof construction.

The precast components were used to span the distance between the columns, strengthening the foundations and increasing the length between them.

“It’s not a well-used system for the roof of a building, but it halved the number of rows of columns from four to two. The space now has half the number of columns with 30-metre clear spans,” says Mr. Little.

Further innovations

The reuse of sandstone on the project and the approach to building the Cutaway are just two of the many innovative solutions employed by the project team.

Another was the removal of the caissons – watertight retaining structures built in the harbour in the 1960s for ship repair activities. There were 33 caissons joined together on the foreshore that needed to be removed for the project.

A specially designed marine wire saw was used to separate the caissons into moveable sections four metres below the surface of the water.

A 600-tonne barge then lifted and transported the caissons, cut into 380-tonne segments, to another section of the site, travelling through a live traffic channel in the harbour 33 times without incident. The concrete structure was then crushed for use on site.

An existing 100-year-old heritage pump station on the site also had to be relocated. This proved to be a logistical conundrum. As the building was fragile brick, it required two cranes to lift it simultaneously onto a trick and drive across the site. Incredibly, the building was successfully relocated and repurposed into a modern day public toilet.

Sustainable outcomes

Environmental outcomes and sustainable practices were outlined in the construction brief for the park and, as Mr. Little explains, some inventive thinking was required.

The reserve’s water reuse system, for instance, became an important element in achieving some of the sustainability targets set out before the project team.

An integrated water reuse system, consisting of two tanks – a 1200-cubic-metre rainwater tank and 180-cubic-metre seepage tank – was set up under the Cutaway car park.

Stormwater is captured, treated, stored and reused for the park irrigation.

Through extensive logistical planning and forethought, the project team also reduced traffic movements and emissions throughout the project.

“The construction site had a really small, confined footprint, and every piece of the site has changed,” he says. “A lot of it has changed in elevation. Some areas were raised by 17 to 20 metres in height. It’s changed from asphalt to trees, timber, grass turf and sandstone.”

A landscaping supply contract was awarded to another company prior to the construction team winning the tender for the reserve. Established trees and plants had to be relocated to suit park’s design. “The challenge was to make sure the park looked as mature as possible,” he adds.

Mr. Little says that moving smaller trees and foliage wasn’t an issue, but relocating larger, rooted trees was a tricky process. More than 20 mature fig trees, some 25 years old, were sourced, transported and replanted at the reserve.

Cultural significance

While trees and foliage helped to give the area an established and natural feel, some interesting finds along the harbour foreshore uncovered some of the site’s rich history.

“When we were excavating the cove we were looking at an overview of the area using original nautical maps and oil painting,” says Mr. Little. Due to that information, the team discovered that where they had intended to build, right at the point of the foreshore, was once the site of the 1830s Munn’s slipway.

Likewise, a seawall, estimated to have been built in the 1850s or 1860s, was discovered along the foreshore. “It was very much intact – it was quite a surprise it hadn’t been destroyed,” says Mr. Little.

The slipway and seawall have been preserved as part of the project and are now integrated into the design of the reserve.

Recognition and project outcomes

Mr. Little says one of the main aims during construction was to keep the public involved every step of the way and make the process as transparent as possible.

“For a long period at the start we had the public coming through the construction site, and we maintained that as long as possible,” he says. “The more informed people are the more prepared they are.”

Over the course of the three-year project, construction progressed smoothly without disrupting Sydney Harbour, local amenities and public visiting the area.

The project team undertook roughly 1.5 million hours on site without injury thanks to the safety procedures and systems. “To build a project like this and finish with an exceptional safety performance is one of the team’s proudest achievements,” he adds.

Barangaroo Reserve was officially opened to the public in August 2015, and it has since received praise and recognition from the public and the infrastructure industry.

Besides winning IPA’s 2016 Infrastructure Project of the Year, Barangaroo Reserve has won a number of other significant industry awards. These include the Australian Institute of Landscape Artchitects’ 2015 NSW President’s Choice in Landscape Award; the World Architecture New Waterfront 2015 Award; and the 2015 Banksia Sustainability in Design, Build Award for Buildings, Landscapes and Infrastructure Projects. It was also a finalist for the 2016 Australian Construction Achievement Award.

The accolades have been a great achievement for the project and Mr. Little says that impact on the project team was a real winner for him.

“The enthusiasm in the team to make it special was infectious. Everyone brought their very best to the project because they were aware of the significance of what they were creating,” he says.

“It was one of those developments we knew was special and for the team it was a once-in-a-career kind of project.”

Mr. Little says that the complex logistical and engineering challenges on the project were tough, but rewarding, especially given the outcome.

“To be involved in this project – an engineering playground that has become an iconic attraction was a tremendous honour and privilege.”

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