Bamboo has been gaining momentum as an attractive and sustainable building material over the past decade. Particularly popular on the Asian subcontinent, where the plant is most abundantly grown, bamboo architecture has a long and unsung history. Structural design codes for bamboo were only published in 2004. However, it was not until the twenty-tens that global audiences gave widespread attention to the material’s full structural potential, due to the pioneering work and rise of firms such as Vo Trong Nghia Architects.
Though long touted for its use as a finishing material, it wasn’t until large-scale projects, such as Bamboo Wing and Naman Retreat Conference Hall, in Vietnam, showcased the soaring beauty of bamboo that the structural material’s structural merits were popularly considered. Why the plethora of mesmerizing bamboo pavilions in recent years, but fewer skyscrapers, residential or commercial structures? What types of research are being undertaken to harness bamboo’s strengths and ameliorate its shortcomings?
When it comes to tensile strength, bamboo performs significantly better than steel; the former clocks in at 28,000 pounds per square inch while the latter carries 23,000. Meanwhile, while this strength profile is said to be comparable to hardwood species, its hollow core makes bamboo extremely light-weight and elastic. Why, then, do we not simply replace steel with bamboo?
Due to its thin walls, small amounts of damage can have an outsized impact on the material’s performance. Beetles, termites and rot due to moisture are the three main culprits in these cases. If left untreated, bamboo will last less than one year outdoors, and up to about 5 years inside. Meanwhile, salt treatment can extend the life of bamboo structures up to half a century. While detractors may see this as a flaw, sustainability advocates would point to the fact that some concrete structures, which are far more carbon intensive to construct, are demolished along the same timeline. Borax treatments can also protect against bugs. Even when treated, the bamboo must be kept fairly dry.
There are over 1000 species of bamboo across the world, each with a unique profile of structural straights and possibilities. Some designers, who are particularly attuned to the nuances between species, choose to mix varieties in order to maximize strength and flexibility of their designs. Researchers continue to expound upon the distinct mechanical and physical characteristics of the species, pointing to which ones are most useful in various situations. Structural merits aside, certain varieties of bamboo also hold a record as being the fastest growing plant on earth, reaching new heights of up to 3 feet in just a single day. This means that within just five years of planting, material can be harvested for constructional use.
Additionally, as it has gained traction in wider architectural communities, the material’s use in larger projects pushed innovation; by 2018, for instance, Chiangmai Life Architects created bamboo trusses that were prebuilt on site and lifted into position with the help of a crane, spanning 56 feet without steel reinforcements or connections. While previous structures of a similar scale relied on bundling and bending bamboo into massive vaults (particularly amenable to pointed arches), the process is continuing to develop.
Around the same time, SUP Atelier began exploring the possibilities opened up by using digital simulations to generate bamboo structures. On the basis of their conceptual design, they were then able to envision prefabricated bamboo parts, including shaping and bending longer pieces, created in the controllable setting of a factory and only later brought to the site and assembled. The result was a mesmerizing structure, whose swirling, curvalinear lines not only activated the space but also made the structure appear as if it were itself in motion.
While the true scope of research continues to expand, exciting developments are in the works. High-temperature heat treatment processes, such as one developed by the Taiwan Forestry Bureau, are allowing new possibilities for the material, as seen in the flowing space of CHUN-Z studio’s Connect / Digital Bamboo Pavilion.
Four sets of vertical pillars provide structure for the meandering slices of bamboo. Formally, the structure’s upward momentum takes its cue from the axial fibers of the bamboo tube, which have essentially been baked into specified shape, affixed to the columns and woven into curved surfaces, resulting in a flowing spatial effect. This free-form approach creates textures of varying densities, amounting to a unique spatial experience that fuses the form of digitally-designed pavilions with the texture of traditional weaving.
Recently, students at the ETH Zurich have developed an ultralight yet complex structure, combining digitally designed joints, 3D printing technologies and over 900 bamboo poles. In addition to allowing formal possibilities for the expression of bamboo’s innate qualities, it is cost effective and relatively straightforward to produce. Meanwhile, researchers at The Swiss Federal Institute of Technology in Zurich have introduced BambooTECH, a durable and versatile bamboo composite that enhances the natural strength of bamboo.
Compared to the average plant, bamboo releases 30% more oxygen than the average plant and bamboo forests can act as a bulwark against erosion. Unlike trees and timber, you don’t need to kill the plant to procure bamboo — the and stump can be left and so long as there are healthy, mature roots, it will re-sprout and regrow. This makes it a preeminent material choice for building a more sustainable architecture industry. Like concrete in the 19th century, or iron before it, more research is required to make bamboo into a better construction material so that it can be harnessed to build more resilient buildings and the industry is already taking steps in the right direction.