Developed by Hannah Ahlblad, a recent graduate of Wellesley College cross-registered at MIT's School of Architecture + Planning, this article explores the potential of merging bamboo and concrete, harnessing the strengths of both materials to create a sustainable, durable and affordable material for use in developing countries. Hannah’s project was created in conclusion to the semester-long emergent materials elective taught by Professor John E. Fernández, Director of MIT’s Building Technology Program.
In the rapidly developing economies of East Asia and Latin America, urban architecture often seeks to combine the local heritage with the prestige of Western contemporary form and practices. The materials used in urban areas of these growing cities follow the steel, glass, and concrete technology used elsewhere. Usually, emerging materials research looks at the structural properties and applications of materials under scientific development. Less consideration has been given to ancient building materials and their interaction with today’s engineering.
Architects like Steven Holl and Kengo Kuma beautifully experiment with bamboo in contemporary form without pushing their creative approaches into mainstream construction. Our public conversations between natural landscape and modern building technology in China and Latin America remain confined to facades and high-budget architecture. Meanwhile, commonly used construction practices for middle and lower-income housing in the developing world employ standardized “global” methods like concrete masonry or depend on centuries-old structural knowledge of local materials such as bamboo.
Without rejecting the power of concrete and the study of synthetic materials, I wanted to determine a material process that would bring internationalized man-made materials closer to the local landscape. Bamboo cracks with temperature change, tapers in diameter, and its organic surface shows the wrinkles of time. These tendencies all offer a poetry and spiritual constraint to challenge and extract new forms from engineered materials. Within this dialogue, I experimented with the interactive functionality of bamboo and concrete to define a new phenomenological language.
My inspiration came from living in Ponce, Puerto Rico for several months, and studying the city of Manizales, in the state of Caldas, Colombia. In these cities and their metropolitan region, bamboo is used almost exclusively by the urban poor and the eco-tourism industry. In the lush mountains north of Ponce, bamboo groves meander along the winding asphalt roads. Parallel, runs a current of concrete masonry houses that sometimes balance treacherously on bamboo foundations. Instead of advancing and experimenting with forms and the ecology of place, lower-income residents are limited to the two-dimensional joys of a rainbow of Pantone paint colors. How can architecture and building technology become an exploratory zone for the common citizens of bamboo regions, who construct their own communities and homes?
In Colombia and Puerto Rico, bamboo and concrete are sociogeographically separate. Efforts to elevate bamboo’s perceived architectural value in the Caribbean region exclude it from common construction practices with concrete. Instead of reducing the stigmatization of bamboo as a poor man’s tree, bamboo becomes either useless or a symbol of tourist amenities.
Although bamboo is flexible, shock-resistant, and preferable to exclusive use of rebar concrete in earthquake zones such as Colombia, its vernacular use has separated it from the common solutions to earthquake architecture. Bamboo is celebrated as a novel design material, or in traditional tectonics of rural communities. However, I want to implement bamboo as a common building technology in regions where it grows wild.
Bamboo in the designs of Kengo Kuma and Schröper + Hee respects bamboo’s heritage in landscape and its physical strength and geometry. Even in the beauty of their work, these innovative architects are often more fascinated with subjecting bamboo to pre-fabricating parametrics and visual effect. Building technology is all too often left to be sorted out by the engineers, and then oriented towards manufactured materials and established systems. Simón Vélez in Colombia is a champion of bamboo’s dynamic structural potential. However, his disdain for concrete limits the possibility for his architecture to drive bamboo into a new language for daily urban life.
What would happen if bamboo constrains and redetermines the nature of manmade tectonics both physically and conceptually?
In looking at the bamboo and its precedent uses in historic architecture as well as contemporary configurations, I realized that not much attention had been paid to joinery methods between bamboo’s semi-cylinders.
First, I cut short cylinders of bamboo excluding each node. These cylinders were then split in half along the pre-existing cracks that had formed over the bamboo’s drying process. These halves were linked as shown above. By drilling holes for a steel wire to pass through, the semi-cylinders could become laced in a straight chain of undulations. The space of interlacing parts could then be filled by aerated concrete, whose porous consistency was intended to adhere to the fibrous interior of the bamboo.
Curving walls were inspired by JOHO Architecture’s concrete Curving House bricks whose own form was derived from the site’s nearby Mt. Gwanggyo, Korea. By stacking my bamboo-concrete chains through more narrow bamboo poles, the longitudal bamboo would be cast with concrete and act as a support beam around which a bamboo-concrete lace could pivot (model from folded paper, above).
PROPOSAL 1: Puerto Rico
This potential site was chosen with consideration to the lack of transition between the edge of asphalt roads and tropical forests in Puerto Rico. The proposed bamboo wall curvature mirrors the curving bamboo grove and provides an insulating rest stop along the roadside of the Cordillera Central Mountains in Puerto Rico.
PROPOSAL 1: Bogotá
This imagined (3d-printed) pavilion employs bamboo-concrete lace in the urban context. The pivoting embracing structure intervenes with the city street and the cold blocks of neoclassical stone and brutalist concrete in downtown Bogotá, perhaps in front of the Ministerio de Agricultura. The pavilion is inspired by the idea of a temporary house or shelter in the midst of permanent, historic buildings and monuments.
While the concrete adds solidity to the lace, the warmth of the bamboo exterior reminds the pedestrian of another world outside the city, or under the bamboo’s canopy.
Aalto’s Savoy vase and its fired wooden mould inspired my take on the practical applications of a combined bamboo and concrete system that addresses form, functionality, and surface.
Aalto created his initial prototypes by placing wooden sticks in the ground, and blowing glass into their cavity. I looked to this method of formwork, but using bamboo grass as the cheap omnipresent material of the Caribbean countries and Colombia. I wondered if it might also contribute structurally.
The use of bamboo solely as a geometric formwork for the concrete evolves from Aalto’s Savoy glass, and the use of bamboo to create a ribbed facade at Steven Holl’s Sifang Art Museum in Nanjing. Here, the natural element adds to the decorative faces of concrete, and also allows for a separate game between human and vegetation, between the designer and bamboo, to determine the concrete’s future.
In his book, "Studies in Tectonic Culture," Kenneth Frampton introduces the German architect Gottfried Semper’s analysis of the Caribbean Hut at the Great Exhibition of 1851. Semper proposes that earthwork is a "stereotomic, topographic mass" on which lies the more transparent "tensile frame". In the presented bamboo-concrete tension wall, the bamboo itself acts simultaneously as the wall’s topographic map and its tensile frame. Man-made concrete reinforces the organic framework that surrounds it in a symbiotic system of compression and tension.
Further investigations into these technologies would require investigating the tension system of a strung bamboo formwork that surrounds a solid concrete frame of a building. How can bamboo formwork simultaneously function as a structural exoskeleton to replace concrete’s standard steel and rebar reinforcement? Given appropriate additions to the prototype, bamboo’s concrete tension system could be used in multi-story construction.