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Rib System

 

American Ingenuity's Dome Building Kits are erected using a system to temporarily hold the panels in place until the seam concrete and concrete on the entryways, dormers, cupola and link has cured. The systems (Rib or Radial) are dismantled upon completion of the dome and the 2x4s are recycled as part of the interior framing. Shorter 2x4's can be used to frame the second floor perimenter knee wall. Behind this knee wall, electrical, plumbing or ducting can be run or the space can be used for storage.

The Rib System consists of using your own 2x4s and steel hubs on loan from America Ingenuity to assemble a free standing framework which matches the geometry of the dome.

  • The rib system dictates exact panel placement.
  • Once all the seams, entryways, dormers, link, cupola, etc. have been concreted and the concrete has cured, the rib system is disassembled, the hubs are returned to American Ingenuity and the 2x4s are recycled as interior framing. The shorter 2x4's are used to frame in the second floor perimeter knee wall.
  • As the building kit is being assembled upon the temporary wooden rib system, extra 2X4s are used to support the panels and the rib system.
  • The hub rental charge is a $800 deposit with the hubs being kept for four months. After that the rental fee is $10 per month. If the hubs and bolts are returned to us intact within the four month period, the complete deposit is returned. Thereafter, we subtract $10 for each additional month the hubs are kept and we subtract money for each hub that is missing and return the deposit difference to the client. The hubs are returned to A.I. via UPS or common carrier at the client's expense. Please box the hubs in a sufficient number of boxes to assure that the boxes are not too heavy for the trucking company employees to move around.  When boxes are too heavy or improperly taped, they rip open during transit with hubs and bolts being lost along the way.
  • The Rib System is bolted together from your 2x4s and color-keyed hubs on loan from A.I. It is usually assembled on the ground working from the top to the bottom and hoisted up as you add each row below the last. A scaffold tower (which we illustrate in our Assembly Manual) or a long reach lifting device can be used to lift the rib system.
  • This means the first row that is assembled is the top row. Once assembled this row is hoisted up and the fourth row of 2x4s and hubs are added to this row. This continues until the third and second rows of 2x4s and hubs are assembled and hoisted up. The last row that is assembled is the 2x4s and hubs for the riser panels. See the Rib System pictures below.
  • The advantages of using the Rib System Option versus the Radial System Option are:
    • With a Rib System in place, a crane can be used to set as many as 2 rows of panels in one day.
    • Since the Rib System reflects the dome geometry, a panel cannot be inadvertently positioned incorrectly.
    • The Rib System is most suitable for a large crew and for fast paced construction.
    • The Rib System is preferable on the 40’, 45’, 48’ and 60' in diameter domes.

Q: Can I purchase the 2x4's for the rib system precut and the holes drilled in them?
A:
Yes. Due to fluctuating prices on the 2x4's please call us for pricing. The pricing will be for the 2x4’s precut to the proper length with a predrilled hole. Add $60 for a second drilled hole for use with a second dome. The 2x4's that are used are lightweight wood, not pressure treated. We ship the precut, predrilled 2x4's on the truck with your building kit. Remember these "supports" are temporary there is no wood in the shell to interrupt the insulation or to rot or for termites to eat.


Q: I would like to have the rib system assembled by the working consultant. Will the working consultant cut the 2x4's to length, drill the holes and assemble the wood skeleton?

A: Yes but he will need laborers to assist him. Click on Kit Assembly Consultant for more info.


Q: How many 2x4s are needed for the rib system?

A: The 22’ and 27’ need 75 - 2x4s eight feet long. The 30', 34', 40' require 135 - 2x4s eight feet long. The 45' and 48' require 135 - 2x4s ten feet long. The 60' needs approximately 200 - 2x4s.


Q: Can I remove the temporary supports too soon?

A: Yes you can. The dome shell is not self supporting until all the panel seams are concreted and all the building options have been concreted. This means "Do not remove the rib system until the concrete on the dormers, entryways, link, cupola and seams has cured."


Q: Why can the dome shell be self supporting with no need for interior load bearing walls to support it?

A: Manufactured geodesic dome home kits are constructed using a triangular network to form a spherical shape. The triangle shape is the strongest shape known to man. The geodesic dome construction method using triangles, provides for a free-span, self-supporting structure requiring no internal supports such as roof load bearing partition walls. This allows for maximum flexibility of floor plan design and utilization of interior space.

As an architectural form, the dome is one of the strongest structural forms devised and built by man. Domes that were built centuries ago enclose many of the great cathedrals of Europe. Domes are structurally superior to rectilinear enclosures. The partial sphere is an aerodynamic shape that is very stable in high winds and can withstand heavy snow loads. For these reasons, residential domes greatly exceed the structural requirements of the major building codes in the United States.

The dome, or partial sphere, is a geometric form that encloses the greatest amount of volume with the least amount of surface area. Historically, massive domes constructed of stones, brick or concrete were common in ancient Greece and Rome. In modern times, Buckminster Fuller was the first to formulate geodesic principles for constructing a spherical surface by triangular subdivision.


Q: What methods are used to lift the panels?

A: The methods used for lifting the panels includes; Small cranes, Highlifts (all terrain scissors forklifts often used by roofers), and A steel scaffold rigged with wheels and winch. Other lifting devices successfully employed by our dome owners include: a boom added to a tractor, a block & tackle, & a hoist fastened to the top of the framework with wood ramps up the side of the dome.

Monthly rentals on transverse lifts also called Boom Lifts, Horizontal Boom Fork Lifts, Roofing Lifts, Shooters are available from National Rental Chains like US Rentals, Hertz Equipment Rentals, United Rentals, etc. The companies can be found in the telephone book

We now have a lifting spike that can be borrowed for a $100 deposit.  It makes the attaching of the panels to the hoisting mechanism easier.  


Tools and Materials needed to assemble the Rib System:

  • Set of steel scaffolding to reach at least the dome height plus three feet (the dome height can be estimated by taking one half of the diameter of the dome.)
  • Five cable hoists (come-a-longs)
  • 9/16” wrenches and ratchet
  • 46 hubs, 255 bolts, nuts, and washers (borrowed from American Ingenuity)
  • 15 diagonal braces: 2x4x8’ studs
  • 100’ plus of rope, 500 lb. test
  • Precut and color-coded wood ribs (2x4's used are lightweight wood, not pressure treated).
    • The 40', 45', and 48' rib system requires 135 - 2x4's
    • The 22’ and 27’ need 75 - 2x4’s
    • The 60’ needs approximately 200 - 2x4's.
    • If you do not want to buy the 2x4's and cut them to length, color code them and drill the holes, you can purchase them from American Ingenuity. Due to the fluctuating cost of 2x4's, we estimate the cost when you need them.
  • Two pounds 12d or 16d common nails

 

27' Dome being assembled with rib system
34' Dome being assembled on top of full basement
The rib system has been assembled using the steel hubs and 2x4's.
The riser wall and one row of triangles has been installed onto the rib system.

 

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