|This is page 95 of "Domebook
Two", a book that was published in the 70's and is very hard to find. It was
written by Pacific Domes , and I was able to find it at the local library.
Bamboo grows fast, is free material for a dome framework. It might be
possible to suspend a tent skin or mosquito netting inside, or pull a
stretch cloth over the outside and shoot foam. Tools: a pocket knife and
string. The following instructions were prepared by R. Buckminster Fuller. I
haven't tried this yet.
The geodesic dome, as shown in the assembly diagrams, contains two different
joints: a B joint which occurs at the vertices of all pentagons formed, and
an R joint which occurs at all other points.
The spans from joint to joint are BB, BR, or RR. The arc factors of these
BB=.26030616, BR=.31030984, RR=.32636688.
For these factors, the radius of the dome is 1.00. To construct a 22' dome
(11' radius) the lengths of the arcs would be as follows: BB=2.86',
Cutting and Measuring the Members
There are only two different lengths of members used in the erection.
For a 5/8 dome, 80 B members and 90 R members are required.
A line of color can be drawn around the bamboo members at each measuring
point. Use blue for the B points and use red for the R points.
|The B cross consists of two B members whose lengths are: 1/2 BB plus
1/2 BR plus 12" extra at each end.
||The R cross consists of two R members whose lengths are: 1/2 BR plus
1/2 RR plus 12" extra at each end.
With 12" extra on the end of each stick, there'll be a 24" overlap when the
crosses are assembled.
|Place members at right angles to each other and tie
firmly, but not too tight. During assembly of the dome, the crosses will
twist into proper position as shown.
|In all cases, when looking at a cross with the acute
angles at the sides and the obtuse angles at the top and bottom, the
member going from the upper right hand corner to the lower left hand
corner always passes over the other member.
Stage 1 Assembly
The first stage in the assembly of the dome is the construction of the
pentagons at the top of the dome. This process employs 5 B crosses.
|Step A: Tie together two B crosses as shown in in
the diagram. Note that the end measuring points have the same
designation as the cross to which they are connected.
||Step B: Add two more B crosses in the same manner
as shown in step A.
|Step C: Add fifth B cross between the untied
legs. In order to insert this cross, all crosses will be twisted so that
a regular pentagon is formed.
Stage 2 Assembly
The second stage consists of closing the five triangles around the pentagon.
Use five R crosses.
Again, the end measuring points always have the same designation as the
cross to which they are connected.
At this point, the structure will tend to bow. Turn the figure so that it is
||Lift the assembled figure off the ground to facilitate the addition
of new crosses. Use five bi-ped props. Each prop consists of two bamboo
sticks about 7 feet long, tied together near the top with a cord about a
foot long. These props will then support the dome at equidistant points
from it's apex; first at the five vertices at the top of the pentagon,
later at five corresponding points on the top five hexagons.
For the third stage, use ten R crosses as shown.
The fourth stage uses 5 B crosses which close the five hexagons.
The fifth stage uses ten B crosses to close ten triangles. Six of the
crosses can be seen in the diagram above.
The sixth stage uses ten B crosses and ten R crosses to complete the first
horizontal band. We now have a 3/8 dome.
To complete the 5/8 dome requires two stages. The seventh stage uses ten R
crosses and the eighth stage uses ten R crosses and ten B crosses. On the
last twenty crosses, all members pointing towards the ground should be cut
off 12" from the cross' central point.