Geodesic Dome Engineering

Every dome kit manufacture has a web site nowadays. Look at their pictures and see how many people it takes to build their dome kits and how big their components are. Not even the most experienced construction person wants to handle a 300 pound plywood hexagon 20 feet in the air. How many days can you afford $600 for the crane and operator.

Putting the frame up is not the only phase of construction to be concerned about. Fifteen and twenty sided foundations are always fun for even experienced form carpenters. Exterior sheathing and roofing can be a challenge if your triangles are out of alignment. Which is very common on the bolt together steel hub design. Even a quarter or half inch can cause real headaches and a rise in construction labor cost.

On the 3V geodesic structures the triangles are 7 to 10 feet tall. On a 4V geodesic structures the triangles are 4 to 6 feet tall. The smaller triangles are much easier to handle when doing the out side plywood sheathing or inside drywall.

I don't believe there is any structure more spectacular inside than a spherical geodesic structure. After 40 years I have find building boxes to be very boring. They do have their advantages. They tow down the highway pretty well and you can stack them very close together. Dome Kits .info

The two greatest problems facing any structural design engineer is weight and compression from gravitational pull and shear quality against wind loads and earth quacks. The spherical shaped geodesic structures and domes will always have the advantage over the square or box shaped structures.

As the geodesic structures becomes lighter and stronger with height, the rectangular shape becomes weaker. The triangle is the strongest geometric shape and the triangulated sphere the strongest structure. The weakest area on any rectangular or spherical structure is closest to the ground or foundation. With this thought in mind the worst structural engineering idea is to put a rectangular wall at the base of a triangulated sphere. To properly incorporate rectangular riser walls under a geodesic structure you must take the time to change all the geometric history to integrate square walls under the triangulated sphere.

One of the construction challenges to the 3 frequency icosahedrons is it has no flat line (horizontal great circle near the hemisphere) to attach to the foundation and a rectangular riser wall is used by most dome building manufactures. The use of a separate independent rectangular riser wall completely undermines the structural integrity of the triangulated geodesic structure (Geodesic Dome Truss).

Most all dome kit manufactures use a 3 frequency icosahedrons for their geodesic structure designs. Having less triangles than a higher frequency makes for less components to manufacture. The larger triangles also help in placing and framing rectangular windows and doors.

The 3 frequency icosahedrons struts (made of wood) and connections become to weak to safely support the structure larger than 35 feet in diameter. For larger buildings you must go to using the 4 frequency and higher geometric designs. The 4V (frequency) icosahedrons is flat at the hemisphere. With almost twice the amount of triangles and the struts almost half the length, the 4V geodesic structure can safely be built twice the size or diameter as a 3V geodesic structure.

The construction industry continues to change as every other technology. New materials and technologies are being used to build the latest projects usually by the lowest bidder. In the big cities inspections are pretty strict and usually have competent inspectors. Out in the more rural areas you may never see an inspector, especially if your building a geodesic structure.

All spherical and box shaped structures are required to have an engineering stamp of approval. You can find engineers to stamp anything and risk losing their license if the building falls down. It is sad to see that we will never see the end of poorly engineered products in the hands of unknowing consumers for the sake of a fast buck.