Building New York’s 21st Century Superscraper | The B1M

With more supertall skyscrapers currently
under construction than were built in the entirety of the previous century, New York City’s skyline is changing like never before. While the iconic Empire State and Chrysler
Buildings have dominated Midtown since the 1930s, one of the largest buildings New York
has ever known is about to join them on the skyline. First conceived as far back as the early 2000s,
the developers of One Vanderbilt began purchasing buildings adjacent to Grand Central Station
with plans to construct a major new office tower on the block bound by Vanderbilt and
Madison Avenues and by 42nd and 43rd Streets. Having been postponed by the onset of the
global financial crisis in 2008, plans for a commercial skyscraper, 1,300 square metres
of redeveloped pedestrian space along Vanderbilt Avenue and substantial improvements to the
Grand Central Terminal transit network were first unveiled in 2014. Designed as a modern take on New York’s
famous tapering skyscrapers, One Vanderbilt carefully responds to its surrounding context while respectfully paying homage to the skyline that it joins. While many of New York City’s historic skyscrapers
tapered through set-backs that allowed natural light to reach street level, One Vanderbilt
streamlines this concept with tapering sheer walls that rise as four uninterrupted forms, these elements culminate in a breath-taking summit. Rising 427 metres above street level, the
tower will stand taller than both the nearby Chrysler Building and the Empire State Building,
and upon its completion will contain one of the city’s highest outdoor observation decks. One Vanderbilt achieves its height by purchasing
air rights from a number of surrounding properties and effectively stacking them onto its site. Despite the building’s height, the tower will
contain just 58 habitable floors – far fewer than other skyscrapers that are comparable in size. This is due to substantially high storey heights
throughout the structure, which range from 4.5 to 6.1 metres – considerably above average. Rising directly alongside one of the city’s
most historic and well-known landmarks, the base of One Vanderbilt has been carefully
designed to improve pedestrian access around Grand Central Station while nodding to the
terminal’s heritage. The new skyscraper’s base is formed from
a series of angled cuts that create a visual procession from the tower to the station’s
grand facade, while a striking sloping ceiling rises 32 metres above street level, opening
sight lines to the terminal. In addition, the glass and terracotta materials
employed across the tower’s facade hark back to those used during the early 1900s
when the station was first constructed. Significantly, New York’s Metropolitan Transit
Authority required developers to undertake major improvements around Grand Central Terminal,
as part of their project. From pedestrianising Vanderbilt Avenue between
42nd and 43rd streets to improving links between the subway and rail networks and allowing
for the construction of the Long Island Rail Road’s East Side Access project, One Vanderbilt’s
construction will ultimately enable a further 65,000 commuters to use the station each day. At a cost of USD $220 million, these improvements
are by far the largest private contribution to New York’s transit system to date. With the demolition of the existing structures
on the site commencing in 2015, works to excavate down by 15 metres and remove some 46,000 cubic
metres of material began in February 2017. Constructing a major new skyscraper on a relatively
small site in the middle of one of the world’s most densely occupied cities, is far from
easy – and the challenges of logistics played a key role in how the tower was built. Conventionally, the multiple concrete pours
needed to construct One Vanderbilt’s foundation mat would have taken place over a number of
days, causing congestion and disruption in the surrounding area over an extended period
of time. To avoid this, the project team coordinated
a single continuous pour using four concrete pumps and 420 concrete trucks over a condensed
and highly intensive 18 hour period – an activity that the building’s developer claims was
the largest concrete pour in New York’s history. With foundations in place, the tower’s steel
frame began to rise, reaching ground level in October 2017 and moving ahead of schedule
reached to reach the ninth storey level by February 2018. Unlike the construction of most skyscrapers,
where the concrete core rises ahead of the building’s perimeter structure, One Vanderbilt’s
steel frame and floor plates in fact progress first – a common building technique in New
York City that has its roots in how different trades used to interact on sites. However, forming the tower’s core after
the steel frame had been erected created further logistical challenges – with the core’s
formwork needing to be small enough to navigate through the steel structure to the core’s
location. After careful planning, and with approvals
in place from city authorities, formwork systems manufacturer PERI delivered One Vanderbilt’s
core forming system under the cover of darkness to avoid disruption. With the initial core walls poured, PERI’s
ACS Core 400 formwork system was maneuverered through One Vanderbilt’s steel frame and
installed. PERI’s system creates a safe environment
for those working on the core and has the ability to self-climb the structure as it
rises, avoiding the need to schedule time with the project’s cranes which are always
in high demand on skyscraper sites. As each storey of the core is completed, PERI’s
innovative climbing sequence transfers the load of the formwork system from the upper
working brackets, shown here in red, to the lower climbing brackets, shown in yellow. Hydraulic jacks – shown in green – then push
the entire system up to the next level. The red working brackets are secured to embedded
anchors in the next pour and the load of the core system is transferred back to the red
brackets. Then, the yellow climbing brackets are released, and the hydraulic jacks bring
the lower deck up to join the rest of the core system. This sequence is repeated to the very top
of the tower. Once completed, the core system is dismantled
and lowered down the structure by cranes, either externally or through empty lift shafts. The cranes themselves are eventually removed by other cranes or self-disassemble. One Vanderbilt’s taper means that several
elevator and service shafts within the core do not extend the full height of the building. PERI’s system is designed to be easily reconfigured as it rises, reflecting this element of the
core design. Mindful of the environmental impact that urban
development can have, developers and engineers have gone to considerable lengths to ensure
that One Vanderbilt is at the forefront of sustainability – both in terms of design and
construction delivery. Despite the scheme requiring an extensive
amount of demolition works prior to construction, the project team sought to recycle 75% of
demolition waste and used an extensive tracking system to identify locally sourced materials,
minimising transport emissions. Additionally, the steel rebar used in the
tower consists of 90% recycled content – a significant step up from the standard 60%
– and the use of industrial by-products such as recycled slag and fly ash in One Vanderbilt’s concrete mix helps to further reduce the structure’s impact. Internally, the tower features a 1.2-megawatt
co-gen system that contributes to heating and cooling requirements, while floor to ceiling
windows and column-free floor plates maximise natural light, reducing the extent of artificial
lighting needed during the day. The development also features a 22,000-litre
rainwater recycling system and ultra-high-efficiency fixtures, reducing the tower’s water consumption
by a remarkable 40%. Together, these systems put the skyscraper
on track to achieve both a LEED Gold and WELL certification when it completes in 2020. At a cost of USD $3 billion – and nearly two
decades after it was first conceived – One Vanderbilt is now beginning to make its mark
on the world’s most famous skyline – a highly impressive scheme that blends heritage with
sustainable design and engineering ingenuity to prove this city’s continuing expertise
in skyscraper construction. If you enjoyed this video and would like to
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