“Bamboo is too close to an ideal structural material.” This statement by Neil Thomas during his talk at Bamboo U, which took place in November 2017 in Bali, really caught my attention. Neil is the director of atelier one, a London office of structural engineering, whose outstanding projects include stage and scenography for the Rolling Stones, Pink Floyd, and U2; art installations by Anish Kapoor and Marc Quinn; the Gardens by the Bay, in Singapore, among many others. From a few years to now, the engineer has exhaustive study about bamboo, its structural properties and its most diverse potentialities.
According to him, bamboo is too close to the ideal structural material, beginning with its tubular shape, an open section, such as a channel, is weaker than a closed one because the edge can bend much more easily. Just think of a sheet of paper and how it becomes stronger when we roll it up like a tube, preventing it from bending so much. I
In addition, it has another feature that improves its resistance. The bamboo has longitudinal fibers that leave its base to the top, which are called vascular bundles. The closer to the exterior of the stalk wall, these bundles have a higher density, which makes the piece more naturally resistant. So, the stronger part of the section is further away from its radially centroid, making the piece more resistant. And this is the main difference in relation to a wooden trunk, whose strongest part is right in the center of its section. Another peculiarity is its speed of growth. Unlike hardwood, which can take more than 30 years to be exploited, bamboo can be cut and used between 3 to 5 years, then growing again.
In laboratory tests bamboo also achieves impressive structural capabilities. Its compressive strength is equivalent to the concrete, while the traction reaches the steel numbers. Clearly, this can range according to the species – more than 1500, which grow naturally on almost all continents, especially in regions with higher temperatures.
Even so, there is some resistance in the use of the material, since it requires another type of thinking and the breaking of certain paradigms so rooted in architecture. One of them is the fear of using the material in its rough form, with its irregularities and natural forms. where the beauty of bamboo lives.
There are, of course, some issues that need to be considered, such as the chemical treatment of bamboo prior to its use for construction, to prevent its rotting and insects. Another issue when constructing with bamboo that needs to be considered is the fact that its components should be very well protected from the sun and rain, for adequate durability. This also includes the pillars, which cannot be in direct contact with the ground, that is usually solved by adding a piece of rock over the shallow foundation.
The detailing of bamboo and its connections has been historically developed, being passed from one generation to the next through artisan builders, evolving through the understanding of the material itself. In the 21st century, with all the technology we have available, it is possible to better understand the specific forces in different conditions (strain, compression, bending, shear) and apply modern technologies, so that it is possible to optimize the material and to use other materials and techniques, such as shells and membranes, to achieve even more ambitious structures.
Neil concluded by stating that bamboo is the most sustainable natural building structure on the planet and that we are certainly at the beginning of its use in a much broader way. However, its main teaching is that we should not try to adjust the bamboo to the existing rules, but to change them to suit the bamboo.
Two of our editors, Eduardo Souza and José Tomás Franco, were invited by BambooU and the IBUKU bamboo project company to be part of this incredible experience, organized by The Kul Kul Farm at the Green School in Bali, Indonesia. Check out more information on upcoming courses here or through instagram.