July 07 2014 0Comment
Dome Structures

Dome Structures

Introduction to Dome Structures

Domes are and have been a very structural and beautiful means of construction. A dome is an element of architecture that resembles the hollow upper half of a sphere. Many different culture from around the world have used domes when building their structures and have been using this building styles for centuries. Ancient Rome, Russia and the Muslim world applied lofty domes to their religious buildings to create a sense of heavenly transcendence.

There are two different ways to build a dome, the first is geodesic and the second is monolithic. A geodesic dome is a spherical or partial-spherical shell structure or lattice shell based on a network of great circles (geodesics) on the surface of a sphere. A Monolithic dome is a structure cast in a one-piece form. The form may be permanent or temporary and may or may not remain part of the finished structure. This style makes great buildings because of their structural integrity, reduced environmental footprint, and cheaper cost to construct.

Structural Integrity

One of the main reasons why monolithic domed structures are fit for humans to live in is because of their structural integrity. Domes have been known to survive many different types of natural disasters such as earthquakes, tornadoes, and hurricanes. For example, in Missouri in 2003, a tornado ‘sat right on top of the dome and then rolled off into the woods’ with virtually no damage. In addition, a fifteen-hundred year old church in Turkey, which is now a museum, has withstood a significant amount of earthquakes over the years and is still standing with only partial damage. It is still standing because when there is an earthquake, the arches and pendentives distribute the weight equally from the four pillars below. Not only are they known to survive natural disaster, but also man-made disasters such as nuclear blasts and fires.

As well, the structure limits the amount of wind against the dome because of its more aerodynamic shape, which reduces the cost to heat the building compared to a conventionally box-framed house. A great example of a dome’s integrity is St. Peter’s Basilica which was built in 1629. It is the tallest dome in the world. Its internal diameter is 41.47 metres and still hosts thousands of tourists every year to view its structural beauty and painting. Monolithic domes are made out of concrete to provide a strong structure, thought domes have been build with many materials such as wood, ice and even bones. Since the shell of the dome is round, rain will slide down the structure to the ground because of its continuous roof and walls, making no need for an eavestrough.

Environmental Benefits

The environmental benefits are also another reason to build using the dome shaped building method. The utility costs are greatly reduced because of the natural flow of air. Monolithic domed schools save about four times the amount of energy than a traditional shaped school with the same capacity of students. They use about thirty to fifty percent less energy for heating and cooling because they have around thirty percent less surface area than normal buildings. The concrete in monolithic domes are only two and a half to four inches thick, which is about fifty to seventy percent slimmer than conventional concrete structures. Furthermore, since the primal material is concrete, it significantly reduces the amount of lumber used, which provides more trees to take in carbon dioxide from the atmosphere and release oxygen. Given these facts, monolithic domes can easily meet the standards of the LEED (Leadership in Energy and Environmental Design) energy savings criteria.

Cost

Monolithic domes are much cheaper to build and maintain versus the standard structure. They are self-supporting so there is no need for any load bearing partitions, which saves on the lumber and construction costs. For instance, a high school in Texas was built for a total of two million dollars, which cost eighty-five dollars per square foot. They were able to get thirty percent more floor space than the traditional building. Also due to the fact domes are self-supporting and don’t need partitions it allows for larger open areas under the dome then conventional building. A big problem with lumber-framed houses is that there can be problems with termites if the proper air or vapour barriers are not continuous throughout the building. With monolithic structures, the walls, ceilings, and floors are continuous which provides a consistent barrier and is therefore termite proof.

Concrete is a long-lasting material and because of that there is very little maintenance required and the structure can last for hundreds of years. Monolithic domes generally use about fifty to seventy percent less material than a conventional building, which saves on the costs, or you could get a higher quality material because the quantity need is much less. To demonstrate, if you had a cube that is 10 feet on all sides you would need 600 square feet of material to construct it and it would have a volume of only 1000 cubic feet. If you were to build a sphere with the same amount of material it would have a radius of 6 feet and 11 inches and would have a volume of 1382 cubic feet. That is an increase of 38 percent in volume. Thought the design and support systems used to build these domes are often more complex.

Conclusion

Due to the material savings and natural energy efficiency of dome construction new companies are forming that focus on building residential monolithic dome houses. These companies are using new construction techniques to bring this old style of building up to date. New Domes are constructed following a method that requires a tough, inflatable Airform, steel-reinforced concrete and a polyurethane foam insulation. This is becoming a growing market around the world due to the fact Monolithic Domes are neither restricted by climate nor by site location. In terms of energy consumption, durability, disaster resistance and maintenance, Monolithic Domes perform well in any climate, even extremely hot or cold ones.

Monolithic domes provide a building that is structurally sound and can survive just about anything that nature or humans throw its way. Domes have been used to build everything from tiny igloos to gigantic cathedral ceilings. Due to this they have been implemented into our buildings for centuries and are still a means of construction today. They are considered to be green buildings because they are energy efficient. They have been used around the world by different peoples to provide a beauty to their important and religious builds. Finally, monolithic domes are much cheaper to construct than the conventional structure. The Monolithic Dome has a number of unique benefits: construction affordability, healthy environment, disaster protection, energy savings, longevity, all leaning towards the pros of building domes, leaving one to wonder why on an earth that is round, we continue build square structures on it?

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