Domes in the 3rd world

[JimF]

Hi, I am new to the group. I have long been fascinated by geodesic,
and have actually read most of Fuller's books. But I have newver
actually built a dome ( except for models on my kitchen table).

I live in the Philippines having semi-retired several years back. As
you may be aware, there have been several natural disasters here
recently, which have destroyed many local homes. I have been thinking
I would like to encourage the locals to begin considering geodesic as
a relatively inexpensive, yet very strong structure for their homes
going forward.

(Bamboo and concrete are readily available, and most local homes are
built from one (or both). But both the bamboo and concrete homes
suffered catastrophic failures in the floods and earthquakes of late.)

I am thinking of relatively small (25' diameter) 3v domes on brick/
block risers. I am also thinking of 2-3" triangular struts made of
either steel, aluminum or pvc. I am not sure which material makes the
most sense. They each seem to offer advantages.

I guess in any case I would need to fashion hubs similar to the hubs
made of emt, flattened at one end, but made to accomodate triangular
studs(?)

As most of you likely have more hands-on enperience with this field
than I, any advice you can offer that would shorten my learning curve
would be appreciated. The key is that the end result must be
significantly more disaster-proof than what the locals live in now,
and at the same time be affordable to an indigenous population that
lives on a fraction of the income Americans take for granted.

Thanks in advance.
Jim

[Blair Wolfram]

Quoting Jim;

"concrete homes suffered catastrophic failures in the floods and earthquakes of late."

" the end result must be significantly more disaster-proof than what the locals live in now,"

I have never understood the resistance to plywood as a primary building material. I don't know of any materials as light weight, strong, inexpensive or as internationally available as plywood. A beginner carpenter with a hand saw can cut it. Bamboo has great structural frame advantages that can be developed into domes, then cover with plywood.

If concrete has catastrophic failures in situations like the Philippines and Haiti, stay away from concrete, brick and block. It's an obvious decision, yet I've read much of Haiti is being re-built with concrete.

Going back to building with concrete in Haiti is similar to the three stooges working together to nail boards on a house; one stooge holding the board, one stooge holding the nail, and one stooge with the hammer. "When I nod my head, you hit it."

Blair

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[Gerry in Quebec]

Hi Jim,
Sounds like you might benefit from contact with The Sphere Project.
It's an international attempt to ensure disaster relief efforts around
the world are practical, helpful, ethical and systematic -- and don't
repeat past mistakes. The Project has produced a manual, the Sphere
Handbook, which is a set of minimum standards and guidelines for
relief work, including housing for disaster victims. The 2011 edition
is available at the link below.Before you download the file, you have
to read the copyright notice and click on the agreement button.
Chapter 6 is the pertinent section, specifically on shelter. The
information there may be of use in helping with the design a suitable
dome or dome housing project.

http://www.sphereproject.org/resources/download-publications/?search=1&keywords=&language=English&category=22

One last thing, just to be clear....Although it's called The Sphere
Project, "Sphere" isn't a reference to geodesic domes. It may be a
reference to the Earth; I'm not sure.

Good luck,

Gerry in Quebec

[Dick Fischbeck]

Here is another relevant link.

http://sheltercentre.org/library/transitional-shelter-guidelines-review-draft

On Sat, Feb 25, 2012 at 5:25 AM, Gerry in Quebec <toomey...@gmail.com> wrote: 

.

http://www.sphereproject.org/resources/download-publications/?search=1&keywords=&language=English&category=22

[Paul Kranz]

JimF:

My favorite way to construct a geodesic dome is the panel or Pease method. The nice thing about it is that the only thing you do in the air is hold up the panels and bolt them together.  http://domes.com/dome_brochure.pdf  was my original inspiration for the Pease system. This means that all of the construction is actually done on the ground, where I would rather be. The process is to construct a 2 X 4 panel and use it as a plug to construct a mold (jig) and then mass produce the panels from the mold. You would need a separate mold for each triangle shape.

My preference is to have no dimension greater than 8' and if the dome isn't big enough add more triangles (increase the frequency). For example, a 2-freq icosa with an 8' control dimension is nearly 26 ft in diameter and covers almost 500 sq. ft.

I would recommend a Pease construction method with a 2-freq icosa with an 8-foot control edge. It has the footprint of a decagon with 8-foot sides. The dome is a full half-sphere with a 13-foot height.

Paul sends...

[JimF]

Hello, please accept my sincere thanks to all who responded to me both
privately and publicly.

I have several new sites and documents to peruse, which I shall be
doing. I'm very happy I found this group, and I look forward to
continuing my dialogue with this group in the weeks and months to
come.

Jim

[JimF]

By the way, I wanted to point out that the catastrophic failures I
mentioned earlier, using bamboo and concrete, happened in different
disasters.

The concrete, including rebar reinforced concrete, failed in a recent
earthquake. Bamboo bailed in a case of flooding. In the latter case
there was a tremendous wall of mud which struck an entire village in
the middle of the night. Bamboo homes were not able to withstand the
mud's onslaught and were literally washed away - in some cases right
into the ocean. Tragically, this all happened in the pitch darkness.
Whole families woke to find themselves neck deep in moving mud. Of
course, even the strong ones had no way to save weaker family members.

This is why I was thinking of a concrete or brick riser, extending
maybe 3 or 4 feet high. It seems that such a foundation would be able
to better withstand similar flooding . A geodesic structure placed on
top of that riser would be able to withstand earthquakes.

Of course, there remains the possibility that in an earthquake the
riser could fail. However, it seems that a short foundation is less
likely to fail than a tall one. And even if the riser failed in one
or two locations, the possibility of the geodesic dome coming crashing
down seems rather remote. Of course, I am not an engineer, so this is
just educated guesswork on my part.

Bamboo makes some sense for the geodesic struts, because bamboo is
readily available and cheap. My concern regarding bamboo is I
question whether it makes sense to rebuild homes using bamboo. Why not
make new homes more strong, given the opportunity? I was thinking of
either metal or PVC tube. Mind you, I am not thinking of the 3/4" pvc
tube, but a larger diameter, in triangular form. These materials are
not as readily available as bamboo, nor as cheap, but they are much
stronger and will last a lot longer. And the amount needed (for a 24'
dome) doesn't seem to be price prohibitive. Also, it is difficult
for me to imagine how to fashion hubs for bamboo, since bamboo poles
will not be a uniform diameter....

In any case, initially the domes could be covered with some strong
waterproof material, such as tarp or canvas, to minimize the initial
cost of construction. Over time the roof could be replaced with
something more permanent. Just as long as the struts themselves are
"permanent".

I own a fair amount of land I am prepared to build the first few of
these on, but I figure the "first impression" must be a success, if I
hope to inspire the locals to get excited to commit to a novel design
they have never seen before.

I'm not entirely sure my thinking is on the mark regarding all I have
written here. If anyone has feedback, I'm all ears. thanks!

Jim

[Dick Fischbeck]

glad you asked. ppl need shelter.

[TaffGoch]

Using reinforced concrete, for a raised foundation, and bamboo for the struts, sounds good.

-Taff

[Bazil]

Hi Jim,

my take on bamboo is that

a) it needs to be treated to stop borers and fungus.

There is a relatively simple method that uses minimal pressure to
force a copper sulphate solution through the grain which solves both
of those issues - see abari link below - note where they refer to
boron, I think copper sulphate has been shown to be better.

b) it needs to be kept dry.

It rots quite readily when exposed to moisture so it needs either a
protruding roof or a surface coating or both.

Different species have different characteristics w.r.t a) and b)

From what I have read, bamboo as a construction medium, still may only
be good for 15 years even when a) and b) are addressed. There may be
species that last longer...

It is still a fascinating subject and I am sure there is a lot of
"local" knowledge out there that isn't generally available.

Costa Rica has an excellent program happening

http://en.wikipedia.org/wiki/National_Bamboo_Project_of_Costa_Rica

http://www.guaduabamboo.com/

These are from Nepal

http://abari.org/economic-potential-of-bamboo-in-nepal

http://abari.org/treatment

With regard to natural disasters :-

Domes would be good in earthquakes, as long as floors for different
levels are suitably attached and load calculations for that sort of
shaking were taken into consideration.

In a landslide / mudslide / even wall of water, nothing is going to
resist much. Best chance would be where a dome, possibly connected
across its base by various structural members, rode out the event.
That is, the dome retained its structure and came to rest somewhere
else...

Bamboo for domes presents difficulties.

I will make another post re what I have discovered - and what I think.

Bryan

[Jim Fredrickson]

Thanks for the feedback in re: bamboo guys.  I think I will focus my attention on a different material for struts.  It is a pity that such an abundant material as bamboo is so fraught with barriers to being effectively used for this purpose, but so it is.  Though I must say, the idea of an epoxy plug on the ends, with the plastic straw insert, is fascinating.  I will probably look for an opportunity to test that idea at some point in the future.

 

I am leaning toward steel/alloy triangular tubing, or maybe similarly shaped pvc pipe.    Not as abundant and cheap as bamboo, but available, strong and easy to work with.  I do not have the engineering skill to know the details, but I imagine that as a result of the triangular shape and relatively short strut lengths, 1.5” on edge would be more than adequate to withstand the various forces they would be subjected to.  If anyone here has experience in this area that would be great.  Another advantage of steel is some steel tubing, triangular, comes standard with holes cast evenly along one or more edges.  Those holes  could be useful in many ways.

 

As for hubs, I was thinking along the lines of the “air hubs” shown here:  http://www.domerama.com/dome-basics/geodesic-dome-hub-connectors/   It may make sense to just buy these things (wholesale if possible).   It’s the compound angles that would make me question whether a local steelworker could reliably stamp these out for me.  No doubt a Chinese casting firm could stamp these out cheaply and reliably, but of course, then there’s the issue of needing to place an initial order large enough to make it worth the cost of making the mold.

 

I’m sure all here can understand the issues I’m raising.  If anyone has any insight into these practical issues, that’d be great. 

 

Thanks again!

Jim

 

[Bazil]

Hi Jim,

I didn't mean that bamboo was unsuitable. Just that for long term
structures, there are things to consider.

For short term shelter, it doesn't matter how long it might last.

Another simple hub idea i forgot to mention is as follows.

In a round or even square piece of flat metal (not too thick so as to
be flexible, not too thin so as to have some strength), make a cut
from edge to centre. Then pull one edge of the cut over the other
forming a shallow cone of approximate shape to a vertex, drill and pop
rivet into place. Struts are then bolted to that and two could be used
(an inner and outer) in the case of something like bamboo. For a basic
dome it would probably be sufficient to use bamboo as is.

You mention triangular steel tube. Most people use galvanized round
steel tube. Squash the ends flat and drill suitable holes and then one
bolt is sufficient for a hub. This is overall the simplest and
quickest method. It is not overly expensive and is generally readily
available.

May I suggest making a test dome maybe 10 - 15' in diameter to get a
"feel" for it's strength / stability. Build a bamboo one. Satisfy
yourself what can be done.

Bryan

[Bazil]

I meant to say

not too thick so as to be inflexible, not too thin so as to be too
weak...