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RE: IRAN QUAKE/can we discuss ths?

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Joel:
In the 1975, our firm had a project similar to this in Kaduna, Nigeria. The dome's were formed with blow up gourds, similar to balloons, a variety of shapes determined by the original inventor, Lloyd Turner, AIA. My achieves mention also a Iran project, but we actually sent an engineer technician (Bill Edensen) and the client sent the fabrication equipment to Nigeria, as well as Lloyd going out there.
The gourds were inflated with air and then foam was sprayed over the unit. Then wire mesh was installed and the unit was sealed with ferro cement, installed with a plasterer's pump. I remember subcontracting the shell analysis out to Lockheed's analytic people (they had the big computers then). At that time we were doing a number of ferro cement projects.
The Nigeria project never got built because the equipment got hung up in customs. We also found out that the local people didn't like round homes; they were use to rectangular homes. (Bill Edensen subsequently went to work for Messerschmidt Contractors in Lagos and was introduced to the W-Panel system, which we eventually wrote the engineering design manuals for. The W-Panel people are no longer in business, but their product is similar to Impact Panels (Covington Bros) and Insteel.)
There's also acoustic problems with domes. For years, Lloyd had a experimental dome sitting just south of the freeway in Los Gatos, California, which I believe was eventually taken down, but he did construct a home in the Santa Cruz mountains which have seen some pretty big earthquakes.
Just lately we've been involved with a winery project where the owner wanted to use Pise. This is basically 1000 psi soil cement with steel mesh reinforcing. A number of wineries in the Napa Valley area (Zone 4) have been constructed with this system. The walls range from 12" to 18" thick. Subsequently, the owner has decided to build the winery using the ARXX system, which I like better because (1), it has an ICBO report, (2) I can use any strength concrete and won't have to rely on a special testing program for my anchorages and (3) it goes up quicker and easier.
It's ironic in our latest discussions that Keith DeLapp's civil engineering firm is providing the civil engineer for this project. 

Neil Moore, S.E.
neil moore and associates
shingle springs, california





At 09:19 AM 1/3/2004 -0600, Adair, Joel wrote:
Several years ago, when I was at BYU, there was a professor named Arnold Wilson who was an expert on concrete thin shells. Right before he retired, he had three graduate students working on projects that involved ways of forming small concrete domes that could be used as homes in third world, seismically-active areas. Each student came up with a method of forming a small (about 8' diameter) hemispherical dome reinforced with chicken wire. One student came up with a little slip-forming device. Another filled a nylon tube (kind of like a nylon stocking) with a dry mortar mixture, coiled the tube into a dome, and then sprayed it with water. The third precast the dome wedges, then assembled them. If I remember correctly, the tube method failed, the precast one worked reasonably well, and the slip-formed one was a great success. These little dome-homes were very inexpensive to build, extremely strong, and could be built with very few tools and manpower. It was a pretty interesting little endeavor. 

-- Joel

----------------------
Joel Adair, P.E.
Halff Associates, Inc.
Dallas, TX
jadair(--nospam--at)halff.com
----------------------

-----Original Message-----
From: Stanley E Scholl
To: seaint(--nospam--at)seaint.org
Sent: 1/2/04 7:40 PM
Subject: Re: IRAN QUAKE/can we discuss ths?

Good ideas, Nels. I believe we could be useful if we introduced some
very low cost materials to reinforce earthen materials to resist lateral
loads. One material which comes to mind is bamboo but I am quite sure it
is not available in desert climate areas such as the middle east.
Perhaps we could provide polyethlene strands to be inserted diagonally
into earthen walls to reinforce them. I have been interested in
alternative materials for many years and recently built a straw bale
house. I have also used ferro-cement for water reservoir covers. Does
anyone else have any ideas which could be used for third world
construction in seismic areas?
I am leaving in two weeks for Jordan to help design a school.

Stan Scholl, P.E.
Laguna Beach, CA

On Tue, 30 Dec 2003 21:29:10 -0800 "Nels Roselund, SE" < njineer(--nospam--at)att.net
<mailto:njineer(--nospam--at)att.net> > writes:

Paul,

Seismic hazard reduction in 3rd-world countries is a massive problem --
I don't think application of modern construction techniques to
residential construction are a reasonable option in those countries.
The tremendous number of victims in the Bam Earthquake indicate to me
that most were probably killed or injured in their homes.  What's to be
done about mitigation of residential seismic hazards in a town with
enough adobe houses to kill 50,000 people in an earthquake?  How about a
quick course in Fundamentals of Seismic-resistant Adobe Dwelling
Construction -- who knows enough about that subject to present such a
course -- to folks who are largely illiterate [I assume]?.

Even in the US, there are no mandatory ordinances for seismic upgrade of
dwellings -- not even for URM residences.  [Fortunately, our houses are
usually built of light-weight materials, so that, for us, residential
damage only rarely results in collapse or fatalities].

Worldwide, probably the most commonly used residential building material
is earthen [adobe or some traditional variation -- it's just dirt,
nothing else].  Vernacular residential construction in most areas of the
world cannot take advantage of modern light-weight construction
materials -- those materials just are not available.  Earthen
construction is labor-intensive, but labor is more easily acquired than
the materials that we are familiar with.  And, it's no use asking, "What
are the structural engineers doing there?"  Even in the US, most houses
are not designed by engineers.  In many areas of the world, the
traditional methods of earthen construction are commonly understood and
used by almost everyone in the community and soil is one  material that
is readily available -- often the neighborhood, or the extended family
will work together on building a new earthen house, using the methods
learned from the previous generation -- in  just the way that the
previous generations learned how to build their houses.  No other
building material is readily available; no engineering is expected or
available.

It seems to me that the best first approach to seismic hazard mitigation
for new home construction in poor areas of the world where people have
no choice but to live in earthen buildings would be to start by studying
the traditional methods of a given district, and then develop and
disseminate easy-to-understand and easy to communicate guidelines that
could, with small modification to the traditional methods, incorporate
seismic stability into the local traditional dwelling construction.  The
guidelines would include wall and opening proportions to maximize
in-plane shear resistance; rules for height-to thickness ratios to
promote wall stabilities; making use of light-weight materials for roof
construction [to the extent available]; and details for interconnection
of the walls to the roof.   High priority for a poor district would
probably need to be to find a locally reasonable way of to minimize
massive material overhead by building roofs of light-weight materials
able to resist loads in tension and/or flexure [instead of using such
heavy assemblies as vaulted adobe roofs, or branch-and twig-supported
packed soils roofs].  It seems pretty likely that every local area will
have its own unique best-solution to seismic hazard mitigation -- you
and I will never visualize the needs from our desks.  Easy solutions are
not available and the folks who take on the responsibility of solving
these problems have staggering difficulties to overcome.

If a retrofit technology were at hand, it is likely that, for a family
who is scratching just to keep from starving, retrofit would have very
low priority -- after all, in any given community, a damaging earthquake
is a very rare event and would be seen as posing very little urgency
[death by ill-health or starvation is likely much more probable than
death caused by earthquake shaking].  Even in southern California,
where, in the last 100 years, damaging earthquakes have occurred every
20 years or so, most people have not experienced personal danger in an
earthquake.  So, many building owners continue to resist earthquake
hazard mitigation, and most people have not retrofit their homes for
seismic hazard reduction using available voluntary retrofit methods.  It
only takes a short time after an earthquake before the ground seem very
firm again, and preparation of structures for future quakes begin to
take lower priority.  In any case, useable retrofit methods for
3rd-world nations would probably vary widely from region to region
because of variations in local construction styles and reasonably
available strengthening materials.

Nels Roselund
Structural Engineer
South San Gabriel, CA
njineer(--nospam--at)att.net <mailto:njineer(--nospam--at)att.net>



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