With demand for luxury residential apartments in Manhattan increasing and a severe lack
of land available for development, we have seen the rise of super slender skyscrapers
across the city’s skyline.
While this trend originated and first become identifiable in New York – through structures
like 432 Park Avenue and 53W53 – the phenomenon is no longer limited to the city and is beginning
to have global repercussions.
Around the world, developers are now striving to maximise floor areas and value from small
sites by employing the super slender high-rise technique.
But while such an approach does improve return on investment, the limited site access and
additional engineering associated with building these towers make them much more expensive
to develop.
Now, in Australia, contractor Hickory Group have pioneered a construction method that
uses prefabricated modules to improve quality, streamline the building process and reduce
overall construction costs.
While the project’s using this method have so far been modest in comparison to the super-tall
giants of New York City, Hickory are about to take their prefabricated building method
to new heights
in the form of Australia’s most slender skyscraper;
the 60 storey, Collins House in Melbourne.
Collins House is located in the heart of Melbourne on the city’s prestigious Collins Street.
Famed for its historic streetscape and home to some of the countries tallest buildings,
Collins Street, and Melbourne as a whole is in the midst of a high-rise building boom,
the likes of which Australia has never seen.
With soaring demand for high-rise living and commercial vacancies at an all-time low, at
least 20 skyscrapers are currently under construction, including the city’s tallest building the
317 meter Australia 108.
The demand has driven land values to record highs with a modest site just a block from
Collins House recently selling for over AUD $140M.
Now, developers are pushing engineering
to the extreme in order to make the most of the small parcels of land they are able to acquire.
The Collins House site is a mere 12.5m wide.
Fronting the bustling Collins Street and with
occupied commercial buildings on either side, developers Golden Age had no choice but to
build upward in order to maximise floor area.
As part of the development, air rights were purchased from an adjoining building along
the eastern boundary allowing architects Bates Smart to design a 4.5-metre cantilever over
the neighbouring property and increasing the size of each floor by some 35%
from the 14th storey upwards.
With only one access point to the site, manoeuvring plant, materials and other equipment during
construction was always going to be a struggle.
While the first 14 storeys of the tower are constructed from concrete, Hickory’s prefabricated
structural units form the remainder of the skyscraper’s height.
The use of prefabricated techniques has had a remarkable impact on the quality, speed
and level of safety on the Collins House scheme.
With the majority of components assembled off-site and craned into place within an hour
of delivery, the project’s programme has been reduced by 30%.
These prefabricated modules also reduce the need for external safety screens and barriers
as the building is enclosed once the module is in place.
Being assembled offsite – under controlled factory conditions –
allowed the modules to be inspected and any defects rectified prior to delivery, drastically
improving the quality of the finished product and further reducing downtime on site.
Offering 271 luxury apartments, across its 60 floors as well as a host of residential
amenities, Hickory’s modular system provided a more flexible floor plate that can be adapted
from floor to floor depending on the intended use of each space.
Currently rising toward its 190-metre total height, Collins House will become one of the
tallest prefabricated buildings in the world when it completes in 2019.
While Collins House is some way off the 426-metre height of New York’s 432 Park Avenue,
the slenderness ratio of the two structures is almost the same – at 1:16 and 1:15 respectively
– making Collins House a powerful case study for the prefabrication of other super slender
towers around the world.
With developers and contractors constantly searching for new ways to reduce building
costs, keep standards high and speed-up construction, the success of pioneering methods like this
– and on a building like Collins House – could set new benchmarks for the industry in the
years ahead.
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