Seismic considerations

summary:

This area is in a region of significant seismic activity. Being a medical facility, the ability to withstand a major earthquake is critical. How can this be done using local materials and labor skills? How does this impact the design?

Seismic considerations

Omei Turnbull 1197236159|%e %b %Y, %H:%M %Z|agohover

Nepal is a an area of significant seismic activity. In the last six weeks, there have been three earthquakes of magnitude 4.0 or larger with epicenters in Nepal. (http://www.seismonepal.gov.np/Recent_eqk.htm). In 1934, an earthquake centered in Nepal caused casualties of more than 16,000 people, 8500 of them in Nepal (http://www.seismonepal.gov.np/historical_eqk.htm, http://www.kenken.go.jp/japanese/information/information/event/shaeic/doc/ab4.pdf) Collapsing buildings caused most of the deaths.

Some strategies for earthquake-resistant vernacular architecture (extracted and condensed from http://www.world-housing.net/uploads/vernacular_construction.pdf) are

1. Selection of materials, in particular the incorporation of ductile materials to avoid out-of-plane collapse. In this case, timber and bamboo seem to be the locally available options in this respect.
2. Construction with robust architectural forms, i.e. regular floor plan (circular being best, followed by square) and uniform openings (small and well-spaced).
3. Construction with resilient structural configuration, such as efficient connections between roof, wall, floor and foundation.
4. Construction that reduces seismic forces, such as low-rise, with lightweight roof.

It would seem that designing for construction with bamboo and adobe (also known as green, or unfired) brick would be a good starting point. Probably not coincidentally, these are the materials used by Habitat for Humanity for houses in Eastern Nepal (http://www.habitat.org/intl/ap/141.aspx). Large bamboo appropriate for construction seems to be common in Western and mid-Western Nepal. (http://www.bioversityinternational.org/publications/Web_version/572/ch29.htm

Re: Seismic considerations

turboz 1198025817|%e %b %Y, %H:%M %Z|agohover

I'm really glad you find this kind of informations.

It's interesting in this place we can find bamboo. I studied bamboo in my thesis project in Thailand and I made 2 Workshop where I studied Bamboo and I build a Pavillion in Bamboo during a workshop in north Italy, but its a very particular material. Strong as a steal but really fragile if you don't get some measure of protection and you don't get the right joint.

You can find some photos of the pavillion we build in Italy here: http://www.emissionizero.net/EMISSIONIZERO_The_Bamboo_Pavilion_in_Vergiate_1.html

But it's a specific bamboo that come from the Colombia. His name (of the bamboo) is Guadua. It's the only structural bamboo studied from scientist so far.

Maybe the way in Nepal should be to use wood for the structure and bamboo and straw for the roof, maybe with carton-paper with wax, for the rain protection.

I think we should use only material we can find in the place. Or near. Everything we could reach easy.

Or it shouldn't be so much sustainable.

The best way should be go there but in this time I'm really busy.

Simone Riccardi <> turboy Runo

Re: Seismic considerations

Omei Turnbull 1198091581|%e %b %Y, %H:%M %Z|agohover

The Bamboo Pavilion is a beautiful building!

I've found a lot of resources on the net that suggest ways to use bamboo for reinforcing adobe, but none yet that use it exclusively. As you indicated from your experience, tensile strength is great but joints seem to be a major issue when it comes to stiffening against earthquakes. (I haven't found anything describing any details about Habitat for Humanity's techniques.) My current thinking is that a combination of bamboo and timber, joined with steel fixtures, might be an appropriate compromise between using all local materials and achieving good earthquake resilience.

Do you have any experience using adobe and bamboo together?

Re: Seismic considerations

theoryshaw 1198094835|%e %b %Y, %H:%M %Z|agohover

This is speculation, but my only hesitation with bamboo is that it doesn't seem to be a common building material in this area - having looked through the photos of typical buildings in the area. This could either be because bamboo's too expensive or limited in the area. I could be wrong here though.

Imho, i think we should stick with innovative uses of building materials that we know are cheap and pervasive throughout the reason, corrugated metal, stone, stucco, block, and wood (although wood seems limited as well).

What do you think of the idea of proposing for the competition that we dismantle, the abandoned clinic complex on the hill, and use the materials to build the new clinic lower in the valley. I just have a feeling that even if this complex gets renovated in the second phase, its remoteness is still a hurdle and people will still be unlikely to use it, which in the end would be abandoned again anyway.

Re: Seismic considerations

Omei Turnbull 1198105077|%e %b %Y, %H:%M %Z|agohover

Various thoughts:

Re the availability of bamboo, Achham District was one of the studied areas in http://www.bioversityinternational.org/publications/Web_version/572/ch29.htm. (Note that in this report, Achham is considered to be in Midwest Nepal, whereas I usually see it grouped in Western Nepal). Some of the varieties observed by the author of the report, with the author's comments are

• Bambusa arundinacea [Not so common, up to 1000 m, used for construction purpose.]
• Bambusa balcooa (Dhanubans, Ban bans) [Common, up to 1600 m, used for poles, scaffolding, weaving, house wall, beams, erosion control.
• Bambusa nutans subsp. Nutans (Tharubans, Sate bans) [Common in the hills from 1000-1500 m, not found in terai, used for construction, weaving, poles.]
• Bambusa nutans subsp. cupulata (Malbans) [Common up to 1500 m for weaving, poles, fodder.]

My impression (based only on Internet research, not on any personal knowledge) is that bamboo is second only to mud for being cheap and readily available.

As to its current use, you wouldn't see it if it is being used to internally reinforce the adobe, nor necessarily recognize it if it is being used in other ways. See http://www.habitat.org/intl/ap/141.aspx, for example.

Proposing to dismantle the hospital sounds like it would insert us into the middle of a local political storm. I gather it was politically very difficult for Nyaya Health to decide to expand on the site of the new clinic instead of the hospital, despite its obvious advantages in location. As it is, Nyaya Health's recent statement that they have revised their plans and are speeding up the time frame for incorporating the hospital into their plans from five years to six months sounds more like a political compromise than a practical reality.