Located at 447 Collins Street, Collins Arch is a $1 billion development by Cbus Property and ISPT that pushes the idea of ‘mixed-use’ to an entirely new level.
Spanning a 6,000 square metre (m2) city block, Collins Arch will boast luxury apartments, a five-star hotel, WELL-rated offices, ground-floor retail and 1,900m2 of public open space including a tiered amphitheatre.
Designed by Woods Bagot and New York-based practice, SHoP Architects, the development’s two 164-metre, 47 level towers boast an arch-shaped form that is linked by a spectacular Skybridge.
A total of 184 residential apartments will occupy parts of both towers, including the 14.5-metre Skybridge. Residential amenities are located at level 34 with an additional sky garden located at level 39.
Moreover, the W Hotel will take up residence in the East Tower, with 294 guest rooms across 15 levels (and hosting other fantastic amenities such as an indoor pool, gym, lounge area, dining facilities etc.), while the West tower will contain the bulk of the 49,000 m2 PCA premium grade office accommodation.
A development unlike anything else in its surroundings
Starting from the open crown at the apex, the exterior uniquely cascades down as a series of stepped terraces are strategically placed to allow for most of the building to be habitable by people or green roofs.
Woods Bagot describes that the integration of spandrel bands and soffit materials over the reinforced concrete bones adds texture and depth to the façade articulation, permitting a human scale across the surface. The unified design avoids casting a shadow over the Yarra River and also draws sunlight into the interiors.
Through vertical stacking, each floor plate has been created to dedicate half of the site back to the city as public spaces.
The city block will also contain Melbourne’s first public park in almost 40 years.
A landmark in urban sustainability
In an Australian-first, the Clean Energy Finance Corporation (CEFC) and Cbus Property are targeting industry-leading energy efficiency standards for Collins Arch.
Drawing on CEFC’s $100 million contribution to the project, Collins Arch will feature a range of industry-leading clean energy technologies including high-efficiency air conditioning, energy-efficient façade fabric insulation, built-in real-time energy monitoring and the capacity for residential electric vehicle charging.
The integrated approach is expected to deliver a minimum 20-25 per cent improvement on the development’s carbon footprint.
In February 2019, CEFC CEO, Ian Learmonth, said Collins Arch is a landmark development that will shape the character of Melbourne’s city skyline for decades to come.
“For the CEFC, this investment is about creating new environmentally sustainable standards in our cities, locking in a low carbon approach to building design and management that can deliver positive benefits over the long term.”
Cbus Property CEO, Adrian Pozzo, added: “The industry-leading sustainability features incorporated throughout Collins Arch will help us deliver on our global commitment to achieve ‘net zero’ carbon emissions across our portfolio by 2030.”
The project is targeting a 5 Star Green Star Office, 4 Star Green Star Hotel, 4 Star Green Star for Residential. (v1.1); a 5.5 Star NABERS energy rating for its commercial office space; a 7.0 NatHERS rating and a Platinum WELL Building Rating.
A large task ahead for the construction team
Multiplex was appointed builder for the project and construction officially commenced in October 2016.
Works involved the construction of a complex irregular shaped structure including multiple transfer slabs within each tower; the connection of the two towers by way of the Skybridge at level 34; a unique faceting façade made up of many components including horizontal spandrel projections at each level; multiple building services to accommodate various building uses within different areas of the project; large-format, feature precast panels and columns across ground plane area; a 5-level deep basement structure and the 1,900 square metre urban park.
To give a little insight into this massive endeavour: the project required four tower cranes, six alimaks, three jumpforms and manpower peaking at approximately 850 persons on-site each day.
One of the most challenging yet impressive aspects of the entire construction process would have to be the Skybridge which required building works to be conducted 120 metres above ground level.
Multiplex detailed that significant planning of strategy, logistics and safety was involved in the design and construction process.
Through numerous workshops, planning sessions and external reviews their team developed detailed methods to facilitate the safe installation of elements such as a modular working deck which also acted as a protection deck, enabling other works below to continue during bridge construction.
Multiplex said the ease of installation achieved by their team during the construction and dismantling of the temporary work/protection deck at level 32 was a highlight.
The company noted that despite these works being carried out so high up in the air, due to the modular nature of the deck and the pre-planning conducted leading up to these activities, all works were carried out without injury or risk to the public and construction team involved.
All throughout construction, the team also worked to implement the green star principles and targets for the project including the ongoing monitoring of recycling of site waste.
Looking forward, the structure is expected to shortly ‘top out’, after which the interior fit-out will continue ahead of forecasted completion in 2020.