It’s like the start of a “Dad” joke… what do St Peter’s Basilica, the United States Capitol and City West have in common?
They all feature a Dome as a key part of the structure!
Domes have been used in buildings as a statement of wealth and opulence for hundreds of years. They were an efficient way to enclose vast expanses when other engineering techniques were too prohibitive. These impressive structures were usually reserved for large buildings of note and were relatively cost and material efficient for the large spans that they roofed.
The City West Dome has been in place since the centre first opened on 31st October 1987. At the time it was regaled as an impressive piece of engineering and has become an iconic part of the Perth skyline. But, to most of us, it is more than that.
If you have been a longstanding Perth local, you will have your own memories of driving past the twinkling lights at night as you travelled on the Mitchell Freeway. If you were a child, it was magical, it looked like all the stars had fallen and gathered into one place. Over the years, however, the lights have become a little less bright and a little less twinkly after their 35 years of service.
The structure was tired.
So like a good holiday or a day at the beach can rejuvenate a tired body, or a new top can give a spring to your step, our Dome is getting a new look!
That’s right! We are getting a glow-up!
The Dome we are famous for is getting an impressive upgrade, and when we say glow-up we mean, literally…glow-up!
The new semi-sphere frame has been redesigned and the keen eye will notice that there are many more facets to the spherical shape…the science buffs will know this shape as a geodesic polyhedron, it’s a fancy name for a Dome made up of lots of triangles!
Now, if we get really scientific, it is based on the patents of Buckminster Fuller, the American inventor, and is extrapolated from an icosahedron, which is one of the 5 ‘Platonic Solids’. An icosahedron is a spherical shaped polyhedron made from 20 equilateral triangles.
You will see a pentagon at the top of the dome and five more pentagons equally spaced about halfway down the dome. If you draw a line between the centre points of the pentagons, the resulting large triangle is one of the faces of an icosahedron.
The new City West dome is quite different in geometry to the previous dome which was a “Lamella” geometry and had a 12-sided polygon at the top and concentric circles below.
The structure will be more robust than its predecessor and is a more complex form that is composed of 555 members or ‘struts’ and has 195 nodes or connection points. There are 9 different lengths of struts in the geometry ranging from 1.6 to 2.1 metres in length. The new dome is 20 metres in diameter, and being a hemisphere, is 10 metres high which is the same size and shape that we are all familiar with.
However, the biggest change you may notice is there are so many more lights.
The new structure incorporates almost 2000 LED globes that have the capacity to be programmed with impressive light displays, moving through a multitude of colours and patterns, that can be set with infinite possibilities. It will be far more energy efficient and sustainable even though the number of lights is almost twelve times more than the 157 incandescent globes that adorned the original Dome.
The City West Dome has been delighting kids in the backseat of a car for years as they drive home, tired from a day out with mum and dad. It is a twinkly landmark that even very little ones could spy out of the car window at night.
Hopefully, our new top with all its extra adornments will continue the legacy for many more years and another crop of children will experience the magic of an even more spectacular light show through the rear windows on a sleepy journey home.
…And Dad, when you drive past you can ask “what do St Peter’s Basilica, the United States Capitol and City West have in common?”
Go on, you know you want to!