The Ribbon building in the heart of Darling Harbour would be a challenging building for any terrain – but its location between two major expressways and on the water makes it especially difficult.
The breathtaking new development by Grocon & Greaton is set to transform Sydney’s skyline and form an extraordinary new gateway to the western side of the city’s central business district.
The Ribbon’s dramatic 25-storey curvilinear shape was designed by award-winning architects HASSELL. Grocon engaged Willow [formerly Ridley] in 2016 as part of the delivery team in the capacity of BIM Manager and Documenting Architect.
New Hotel and Retail Spaces
Located on the site of the former IMAX theatre, the $750 million redevelopment comprises a new W Hotel with 400+ rooms and 140+ serviced apartments, 170-vehicle car stacker car parking facility, 400+ seat IMAX theatre, ground floor retail spaces and a revitalised public domain.
It will provide public amenities, retail spaces and office space for Place Management NSW, and is expected to be complete by late 2020.
Besides The Ribbon building, the former SHFA Building will be refurbished. It will provide public amenities, retail spaces and office space for Place Management NSW, and is expected to be complete by late 2020.
Darling Harbour Revitalisation
The site is a key part of the overall Darling Harbour revitalisation, with the new Sydney Convention Centre and Darling Quarter precincts in near vicinity.
However, The Ribbon’s prominence also comes with some significant challenges. Both the design and construction had to contend with the constraints of a major freeway on either side of the planned building, with a significant number of services and subsurface structures abutting the site’s own footprint.
Creating a “Virtual Build”
WillowDigitalTM, the professional services arm of Willow, accelerate digital adoption in the built world. They are providing services from the Design Development stage through to Construction Documentation and Site Services. Willow has created a “virtual build” of the project that helps develop the construction methodology, improve safety and enable collaboration between the key project delivery personnel.
Mohammad Khaled, Willow Associate Principal and Co-Lead Architecture, tells Jobsite ANZ the project would have been very difficult without access to digital models and technology.
Willow has created a “virtual build” of the project that helps develop the construction methodology, improve safety and enable collaboration between the key project delivery personnel.
The Willow team brought together all of the documentation for the architecture and interior, as well as federating the models through Navisworks. The company also has team members co-located with Grocon onsite for a substantial part of the project timeframe.
Khaled explains this modelling had multiple functions like clash detection, cost documentation and validating designs.
Coordinated Architectural and Services Design
It ensured the architectural design and services design were coordinated and was used to create the construction documentation for use on-site.
The architects also benefitted from the use of digital tools. Khaled explains that the project surveyors digitised the site survey data, giving a far more accurate suite of information than conventional surveys. They obtained an incredibly precise and exact position for the elements of the built structure, and as the project design and construction proceeded, it facilitated easy cross-checking.
Digital Scans Crucial
HASSELL had access to the preliminary 3D scans of the roads adjacent to the site as well as digital scans of the site itself. This was crucial information not just for the design of the building in 3D. It also helped ensure the roadway remained accessible for inspection and maintenance purposes.
According to Khaled, modelling assisted with developing and managing the logistics of key tasks such as lifts to ensure they would not impose on this clearance zone.
This included a 4D sequencing study on a method for installing the massive screens attached to the main structure of the building.
The 3D design models and documentation formed the basis of the façade and steel shop drawings too, reducing any potential for error.
“We worked with Grocon on testing different methodologies for the construction,” Khaled said.
This included a 4D sequencing study on a method for installing the massive screens attached to the main structure of the building. The BIM modelling and construction documentation also assisted with some of the more logistical details, such as the location of launching and turning bay zones.
“That was all done ahead of time in 4D sequencing and 3D design,” Khaled said.
A specialist consultant Red Arrow also worked on the project’s digital build. It developed overall 4D sequencing, including the methodology for the piling rigs and tower cranes.
Linking Multiple Models in the Cloud
Khaled notes that piling was another of the project’s complexities. That is because a significant proportion of the works, including piling, needed to be undertaken underneath the waterline. It was also crucial it didn’t affect support structures, including piling of the freeways.
The modelling also enabled the project to have the position of the tower cranes interfacing with the structure effectively. This, in turn, “trickles through” to the final as-built appearance of the building’s core and the penetrations in the façade and structure.
Collaboration for Revit (C4R) was implemented to link the architectural model, structural model, and services models in the cloud, Khaled explained. Cloud-hosted shared information source facilitated weekly coordination sessions between key project team parties.
The sessions were live. Since the live model could be adjusted in real-time, all parties were able to see how discussed changes affected each related part of the building or build process.
“It is a massive change in how things get resolved and documented,” Khaled said.
Very Small Margin for Error
The digital process also helped mitigate the extreme complexity of the site geometry and building design, including the distinctive feature of The Ribbon being a sealed building. Khaled points out all of these factors contributed to a “very small margin for error” allowed in terms of delivery.
“Everything relies on the coordination piece being extremely accurate,” he said. “The digital application clearly shows all the requirements the building will need.”
No Surprises with a Virtual Build
In a non-digital old-school approach to something like services coordination, Khaled said, there may have been an allowance of 300mm or so when it comes to combined tolerances from the design, the structure, the penetrations, and the final services installation with each stage being allocated a small margin.
The digital, virtual build makes every stage finite and exact, meaning the final combined tolerances can be as small as 10mm or less.
“You get all the bits and pieces together so you get an extremely accurate picture of what you will get on site,” he said. “You also minimise the risk of things not fitting. Everything has been done in high-level detail, not as a 2D line on a shop drawing, for example. So, there are no surprises.”
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