Last week Mirvac submitted plans for its flagship Melbourne office development at 477 Collins Street designed by Grimshaw Architects. It will be only the second Premium Grade commercial development built in Melbourne in the last 20 years and Mirvac's largest commercial undertaking in Australia.
The building as a whole has been designed to be multi-tenanted, with floor plates ranging between 1500 sqm (NLA) to 1900 sqm (NLA). Among the design features will be five client floors located every 8 levels, featuring expansive lounges alongside outdoor spaces, with open façade systems incorporating doors that open on to spacious terraces and gardens.
The 38-storey development lies within a pocket of the CBD that is in the midst of rapid transformation. Replacing the current office accommodation to the rear, designed by DCM and PVH in the 80's, 477 Collins Street joins a swathe of eight other large scale developments at the west end of the CBD boasting Collins Street addresses.
The projects in question are: CBUS's mixed-use development at 447 Collins, Fragrance Group's 555 Collins, the for sale 464 Collins residential tower, Equiset's major Rialto revamp, the proposed 710 Collins office tower andLend Lease's Batmans Hill. These join the already under construction 567 Collins and 568 Collins projects.
The 3,899sqm site as it exists today comprises of three parts:
Employing a side core configuration for maximum floor plate efficiency, the proposal is in keeping with the campus-style typology that is prevalent amongst commercial buildings of the 21st Century. The tower is expressed as a series of stacked volumes which visually and physically break up the overall massing and responds to the desire for a multi-tenanted building.
The design allows for the potential of further reduction in scale via the provision of tenant driven atria which puncture the floor plate but sit within the glazed envelope. The architects have coined the term Vertical Neighbourhoods to describe the arrangement of commercial programme and tenant driven adaptability and flexibility.
It is an idea that seeks to address the emerging trends in workplace buildings to connect floors vertically, enabling smaller floor-plate buildings to behave with the efficiencies of larger campus style office buildings.Grimshaw Architects
The introduction and articulation of a shadow line running vertically over the full height of the tower responds to the common wall of the heritage buildings. This allows for a different visual language to the eastern core - very rigid and ordered. In addition to services and plant infrastructure the core has provision for 'client spaces' to Collins Street. The evolution of the building's form is best illustrated in the series of diagrams below.
The 158m tower is setback 3.8m from the rear of the heritage buildings for a total setback of 16.8m from Collins Street. The remaining east, west and south setbacks measure 4.5m from the site boundary.
In addition to heritage and setback considerations the proposal has been designed to comply with the planning scheme's requirement for preventing overshadowing of the south bank of the Yarra during the winter solstice between 11am & 2pm.
Another key consideration of the 477 Collins proposal is the sensitive interface between the new and the existing heritage buildings, and how this might inform the public spaces within and around the site. Retail spaces are located to Collins Street with a business lounge and end-of-trip facilities located within the basement levels.
The commercial foyer allows for the physical structural separation of existing from new while visually tying the components together through a single common point.
It is intended that the heritage buildings be occupied by a single retail tenant specialising in the high end food industry that can connect the heritage buildings together at upper levels, whilst still observing and respecting their varying character, boundary walls and social qualities. This proposed strategy is illustrated in the indicative section below.
In a concerted effort to improve the pedestrian experience along the site's Flinders Lane frontage the existing car parking structure is intended to be visually concealed via a screen. This will be achieved via the use of vertical perforated metal blades which also allow for an animation of an otherwise static facade.
At ground level glazed shop front-type facades have been introduced to provide improved permeability and rise to a two storey datum. These are bookended by two glazed staircases which are intended to frame the elevation and provide glimpses of visual activity through the internal vertical circulation of people.
One of the most interesting aspects of this particular design is its inception. The proposal was fostered via global design collaboration - the outcome of a design charette undertaken amongst four international Grimshaw offices where various ideas were submitted and fused together. This process is described further in the passage below, extracted from Grimshaw's planning application document:
As part of the appointment for 477 Collins Street, Grimshaw, as an internationally acclaimed architectural practice with a wider global network, offered to undertake for our client an international design charette at the beginning of the design process in January 2014. The intention of this charette utilised teams in New York, London, Melbourne and Sydney offices of Grimshaw and provided a broad based approach to design which gave diversity and multiplicity to the initial design explorations and ideas.
It was not run as a typical design competition between several architects, nor was it intended to choose an outright winner, however the process bought to the surface many excellent ideas for the development of the site that could be harnessed into a singular dynamic vision.Grimshaw Architects
Factoring in all the initiatives, considerations and design rigour undertaken by Grimshaw and its team to develop the proposal it could be argued that 477 Collins Street presents the first real next-gen commercial tower to be undertaken in Melbourne. If the high-rise residential towers popping up all over town can be loosely termed as "vertical villages" then 477 Collins and future commercial towers could possibly be best described as "vertical campuses".
Pending pre-commitments, construction is anticipated for 2016 with completion expected in 2019.