Automobile bridges with spans up to 150 feet have been built of bamboo by Jorg Stamm in Colombia (see the Conbam site below for more on Jorg) photo by Jorg Stamm

Bamboo has been documented with over 1,500 different uses. In the area of building, that includes fences, gates, trellises, and every part of a structure. Bamboo tools, utensils, and buildings are an important part of life for half the world's population. In temperate climates around the world, bamboo supply can be maintained indefinitely while maintaining erosion control, watershed integrity, soil health.  What we lack is Summer rain.

As a building material, bamboo is special ­ both because it handles long spans and has such intrinsic beauty.  The main reason we can – for the first time – look seriously at this plant is the joinery system developed by Simon Velez and others in Colombia.

It is the process of establishing the production system appropriate to our culture and time that is most important to think through now.  Gaining access to inexpensive land not usable for any other purpose, choosing appropriate species, allowing the time for maturity, understanding the aesthetics of working with cylindrical materials in a predominantly rectilinear society, learning to find exceptional working stock, and developing a design approach that takes full advantage of both the strength and beauty of the timber bamboo – these are our challenges.

Websites

American Bamboo Society --  especially the Species Source List (all bamboos in cultivation in the U.S., sizes, temperature & shade tolerances) http://www.bamboo.org/abs/
1000 things bamboo -- http://www.bambus.de/infos/1000/indexx.php

Building the ZERI pavilion -- http://www.zeri.org/pavilion/slideshow/pav_small/slideshow.asp

German university site -- http://www.conbam.de

Books published by INBAR -- http://www.panasia.org.sg/ecom/mos/user/webdriver?MIval=MOS&START=1&WINSIZE=5&orgid=33&catid=4

Best source of bamboo books in the U.S. -- http://www.bamboodirect.com

Bamboo Flooring -- http://www.4specs.com/s/09/09649.html

Code approval in the U.S. -- http://www.icbo.org/ICBO_ES/Acceptance_Criteria/pdf/ac162.pdf

International standards by the author of the ICBO Acceptance Criteria, Dr. Jules Janssen -- http://www.bwk.tue.nl/bko/research/Bamboo/iso.htm

In Spanish, from the country getting the most from bamboo -- http://www.asosismica.org/

Walk through several Velez buildings -- http://home.earthlink.net/~montecito/irongrass.htm

Thoughts about bamboo flooring from myself and Christi Graham -- http://www.kqed.org/topics/home/homeimprove/healthyhome-feature3.jsp

Find uses for the much more common small diameters and easily-made splits; Bamboo in tension is at its best (photo by Jaqueline Lytle)

Gazebos, trellises, and arbors like the one I did above are some of the first structure types that people think are associated with bamboo.  They're great, as long as one accepts that they won't last long once exposed to the sun and rain.  Bamboo performs about like hardwoods and our douglas fir structural lumber, which means it splits in the first couple of years of exposure, then it bleaches gray in the sun.  As long as the powder post beetles don't find it, it will last for years, as long as you're ok with the way it looks.  Trellises can last for 20 or 30 years, less in humid, wet climates.  And the ability of this lightweight, strong material to totally transform landscapes quickly is unsurpassed.  But, that's not even the best use of the material.  Our challenge is to find ways to use it indoors where it's luster is preserved and it can continue to look attractive indefinitely.

Sustainability

As an architect with an interest in maintaining my supply of building materials, I find that bamboo meets the basic criteria for continuous use.  It is:

Renewable - The Phyllostachys varieties, most suitable for growing and building in the U.S. where we must deal with frost, will grow 12-18 inches a day once a grove is established. Culms (the living poles) emerge as large as they will ever be in that first six-week spurt, then spend the next three years replacing sugars and water with silica and cellulose. Structurally, they are only useful after that third year, which is about when the culm is not needed by the plant.

5” dia. P. vivax in the SF bay area.  The roots extend into the lawn, excess shoots are transparently mowed

 Plentiful - Our current meager U.S. supply of timber-quality bamboo can increase manifold within a decade with species selection appropriate to the microclimate, water, and nutrient availability. For now, temperate varieties such as Moso are being imported from Asia.  These are well suited to being grown here.

Local - Bamboo concentrates a large amount of fiber in a small land area, creating that rare situation in which a single person can be both producer and consumer of a building material. A bamboo builder is not dependent upon the whims of the marketplace and can create a long-term source of material. Few other materials, besides earth, can make such claims.

Waste-reducing - As is nature's general practice, nothing goes to waste. The leaves are high in nitrogen, making good feed for livestock.  Any fallen leaf compost goes to fertilize the next generation. http://esi.athenstn.com/wwt/Bamboo_Bioremediation.html  But, even more enticing are the statistics for pulling carbon out of the air, potentially reducing the amount of carbon dioxide that contributes to the greenhouse effect.  According to the people at the Zero Emissions Research Institute (ZERI) who built the bamboo pavilion at the top of this page, a bamboo forest can sequester 17 times as much carbon as a typical tree forest.  In a country where a third of the greenhouse gases are attributed to buildings, imagine a building material that, when used locally, not only doesn't contribute to global warming, it solves some small portion of the problem.

STRUCTURAL PROPERTIES

Bamboo is an extremely strong fiber; with twice the compressive strength of concrete and roughly the same strength-to-weight ratio of steel in tension. In addition, testing (Janssen '97) has shown that the hollow tube shape gives a strength factor of 1.9 over the equivalent solid. The reason is that, in a beam, the only fibers doing work are in the top (compression) and bottom (tension). The center is dead weight. 

The strongest bamboo fibers have a greater shear strength than structural woods, and they take much longer to come to ultimate failure. However, this ability of bamboo to bend without breaking makes it unsuitable for building floor structures because we have a very low tolerance for deflection, and few here will accept a floor that feels "alive." On the other hand, bamboo as a 3/4 inch thick finish floor is an appropriate substitute for the standard oak because it installs the same way, is harder and expands less.

Because of the relative scarcity of timber bamboo in the U.S., one of the best uses for this giant grass is as a truss, taking advantage of both its strength and its beauty.

Garden structure for Eric Lloyd Wright with new forms of triangulation and stainless bands to resist splits (design by author)

Preferred Joinery

The “fish-mouth” is the joint required when all the poles are in the same plane – as in the “Not This” truss shown above.  Though common in South America, it is very labor intensive and most gringos prefer to avoid it.

The joint of preference is allowed by the three dimensional truss in the second diagram above, developed by Simón Vélez in Colombia.  This one is a simple bolted connection, but because the bolt alone concentrates too much force on the wall of the bamboo, the void between nodes is filled with a solidifying mortar, increasing the surface area of the joint significantly.

 “Fish-Mouth” Joint