How are Domes Built?
Inflatable Domes are an example of Air-supported structures. They are used in recreational events like- concerts, parties, wedding ceremonies etc.and are also used for specific purposes like planetarium domes.
They can protect the interior from strong winds, dust, and pollution. Being highly portable, they are used in events occurring at the outskirts of cities or large fields. They are also used in events where a large number of the public is anticipated.
Inflatable Domes were first tested in 1970 by Michael.H.Geiger at EXPO’70 (Osaka, Japan). People who like to travel can use them as make-shift homes and this technology can also solve the problem of homelessness in cities.
What is a ‘Dome’?
Before going into details, we must first understand the root word dome. A dome is any architectural element which is hollow from the inside. The shape is similar to an umbrella without a stick.
Domes have been in use since ancient times. One can find these domes at the top of religious structures like temples and mosques and also among Russian, Ottoman, Chinese and Italian structures important from the perspective of archeology.
Why is the ‘Dome’ an efficient structure?
There are many reasons for dome-like structures to be more stable, efficient and much in use, some of them are:
1) Domes allow evenly distribution of air among the interiors and there is no blockage energy anywhere unless artificially created.
2) Domes are self-sustaining structures as the upper part is automatically supported by the lower part due to the specific design, and hence, a ‘dome’ shape does not need pillars.
3) The surface area of domes is lesser in comparison to structures of other geometric designs and hence requires less construction materials.
What is the structure of an Inflatable Dome?
Inflatable domes, as mentioned above, are air-supported structures, meaning the structural integrity is maintained due to the difference in air-pressure at both sides of the dome-membrane.
For the structure to be stable, the air pressure should be evenly distributed throughout the membranes or else the membranes might collapse or develop wrinkles.
How are Inflatable Domes built?
The components of an ideal inflatable dome include:
1) Air-dome Fabric: The membranes of the dome are made up of this fabric. This is a vinyl-coated polyester fabric. This can be of any colour, and you can even order customised designs to be printed on it. Some events also feature company logos over it for promotions. This membrane can be of two types:
● Single-layer fabric: Single layers provide translucency to the dome. This type is used typically for agricultural purposes (where a variable amount of light is needed for plants to grow) or mobile events, industrial events etc.
● Double-layer fabric: Double layer fabrics provide a high level of insulation. They are practically opaque and lights are installed inside the dome. This also provides non-fluctuation of temperature and keeps the dome cool or optimum..
The fabric provides resistance from UV rays, fungus, strong winds and weather.It also provides tensile strength to the structure and reflectivity to the surface.
2) Cable Harness system: The cable harness system which includes wires and pulleys, helps in artificially redistributing the air pressure inside the dome membrane, especially around the corners.
3) Anchoring systems: As the dome is inflated with air, a force is generated which carries the dome upwards. To stick it to the ground, anchoring systems are installed at the corners of the dome. Anchoring systems also protect the dome from blowing away due to violent winds.
4) Inflation and HVAC: The dome needs consistent filling up of air to maintain pressure and constant inflation. Air blowers are used which routinely moderate the filling up of domes with air. Heaters and Air Conditioners are also used to maintain the temperature of the interiors.
5) Lights and Doors: Lights are installed for the visibility, especially inside opaque domes. The doors installed are air-tight to reduce leakage of air.
To conclude, engineering a dome is a fun and efficient process. It is better that people know about this technology as soon as possible because, in the future, one might see a dome at every corner of a street.