The Structures That Defy Gravity | The B1M

While most conventional structures are designed
with a clearly defined centre of mass, advancements in engineering, construction materials and
building techniques have allowed some architects and engineers to conceive a range of awe-inspiring
structures that seemingly reject the laws of physics. Despite each of these schemes appearing unsettling
at first, they are in fact as sturdy as any others. From floating museums that reach into other
countries, to breath-taking cantilevered sky gardens and truly terrifying observation platforms,
these structures appear to defy gravity. Sydney’s One Central Park is a twin tower
mixed-use development with a highly unusual exterior. Not only does the surrounding green space
reach up the facade of the two towers – it also extends far into the sky in the form
of the eastern tower’s cantilevered sky garden. Containing a range of residential amenities
– including an outdoor terrace, barbecue facilities and a plunge pool – the most dynamic feature
of this cantilever is a reflective heliostat featuring 320 motorised mirrors that bring
natural light into the space between the two buildings. Built using a steel truss system, the cantilever
and adjoining heliostat extend an incredible 42 metres beyond the footprint of the tower. While reflectors in the heliostat track the
movement of the sun during the day, by night, an array of LEDs turn the feature into a vibrant
light display. Forming part of the iconic Olympic Stadium
for the 1976 summer games, Montreal Tower was set to support the venue’s retractable
roof along with a range of other sporting facilities. However, despite construction works commencing
in 1973, the tower stalled at 92 metres in height due to design complexities, the weather
and strike delays. It remained unfinished during the Olympics. Originally planned to be built entirely with
concrete, when construction recommenced after the games it was revealed that the tower would,
in fact, be too heavy to support itself if concrete was used as the primary building
material. In light of this set-back, steel was used
to construct the remainder of the tower. Rising to an overall height of 175 metres,
the tower reaches a 45 degree angle making it the tallest inclined structure in the world. The building also features an observation deck, Canada’s largest aquatic centre and,
following extensive renovations in 2018, commercial space that will bring over 1,000 people into
the tower each day. Heading south and into the United States,
we come to one of the world’s most adrenaline-inducing structures – the Grand Canyon Skywalk in Arizona. Cantilevering 20 metres out over the edge
of the Grand Canyon, this observation platform places visitors on a glass walkway above the canyon floor. Built in conjunction with the native Hualapai
Nation, this impressive platform required considerable engineering to achieve its structural
stability. The platform consists of an inner and outer
beam that are anchored to four posts on either side of the platform. These are in turn anchored in pairs to four
large concrete footings which are themselves anchored 14 metres into the bedrock using
high strength threaded rock anchors. Additionally, to mitigate any vibration caused
by wind and pedestrian loads, two tuned mass dampers are installed on either end of the
platform, while a third damper is positioned at the platform’s greatest extent from the
canyon wall. Only 120 people are allowed on the platform
at any time, despite the structure being engineered to hold 822 people without overstressing. Built to commemorate the 50th anniversary
of the Timmelsjoch Alpine Road connecting Austria and Italy through the Tyrolean Alps,
this museum cantilevers 16 metres out from the mountain while effortlessly paying homage
to its surroundings. While it appears to be perched precariously
on the edge of a small hill, the mound cleverly hides the building’s foundations which are
buried below ground and act as a counterweight to the protruding structure above. The cement used to construct the museum was
blended with rocks and pigments from the surrounding area, allowing the structure to almost merge
with its context. With the region of Tyrol changing hands between
the two countries throughout the centuries, the museum was built on a symbolic site along
the pass. While it’s foundations and entrance lie
in North Tyrol – part of Austria – the opposing panoramic window at the end of the main structure
in fact lies in the Italian territory of South Tyrol. The striking CMG Headquarters in Beijing features
one of the largest and heaviest cantilevers in the world. Consisting of two inclined towers connected
via a skybridge, the cantilevered element of this structure contains up to 13 storeys
at its deepest point that is suspended 162 metres above the ground. To achieve this remarkable feat of engineering
in an active seismic zone, engineers devised a unique diagrid exoskeleton to carry the
structures extreme loads and transfer them through the superstructure of the building. Demanding more than 40,000 structural elements,
this exoskeleton can be clearly seen on the exterior of the building. The irregular pattern of these elements is
a response to the varying levels of stress acting on the structure, with tighter diagonal
patterns indicating areas of particular intensity. With 17,000 tonnes of force acting on some
of the building’s columns under normal circumstances, it was imperative that the steel used in construction
was of uniform temperature when the two towers were connected, minimising any additional
stresses that could arise from misaligned structural members affected by varying changes
in temperature. To ensure this, workers only connected the
towers during the early hours of the morning, before the sun rose. While each of these structures are in fact
firmly secured to the ground, the engineering and technology that allows them to stand strong
while inspiring wonder is a testament to the capabilities of our incredible industry. If you enjoyed this video and would like to
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Dereck Turner

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