Can Bamboo Construction Material Replace Timber and Steel? | Built (2024)

Bamboo is a versatile material,used to make paper and bed sheets.Itis also strong enough to use as scaffolding for skyscrapers and has a long history of use inverticalconstruction.Inaddtion, the material isin demand as flooring and decorative elements due to its biophilic design aesthetic.

The question researchers have been exploring is whether bamboo has the mechanical properties needed for use as a structural building material. As booming populations need more housing, governments,nongovernmental organizations (NGOs) and industry are looking for sustainable alternatives to meet the growing demand.

Bamboo may be that alternative. Its current structural use is mostly limited to temporary, low-cost structures or bespoke, luxury buildings. For bamboo to have widespread environmental and social impact, itmustbe validated as a commercially viable construction material.

What makes bamboo exciting

Bamboochecks many of the boxes ofan eco-friendly construction material. It’s widely available and inexpensive, particularly in areas of the world with growing populations. As a lightweightlocal material, using bamboo minimizes the environmental costs of harvesting and transportation. Bamboo also sequesters carbon both as it grows and afterharvest, making itpotentially carbon-negative.

Bamboo’s renewability credentials far exceedtimber. It can be harvested withinthree to fiveyears of planting, as opposed to thedecadestimber requires.Itregrows without needing to be replanted, whichprovides additional environmental benefits. Its large root networkalsoprotects against soil erosion and landslides.

Of course, none ofthis mattersif bamboo’s mechanical properties can’t bear structural loads. A growing body of research shows that certain bamboo species have impressive and efficient mechanical properties, including possessing a strength-to-weight ratio equal or better than that of steel and lumber. Certain bamboos also have the compressive strength of concrete.

“Bamboo has hundreds of fibers surrounded by lignin matrix that bind the fibers together,” said Dr. AlirezaJavadian,a co-author on numerous studies on bamboo’s potential in construction. “These fibers are a major point of load transfer that provides its strength.”

Bamboo’s strength and flexibility have provenbetterat absorbing seismic activitythan more common building materials. A collection of bamboo houses withstood a 7.6 magnitude earthquake in Costa Rica in 1991, while wood and concrete houses in the same area suffered damage.

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Bamboo’s greatest weakness is its poor durability in its natural state.The materialattracts insects and fungus, which cause decay, anduntreatedbamboo structures don’t last more than a few years.Part of the growing body of research looks at how treated and engineered bamboo products compare to steel, concrete and timber. They’re looking at its potentialto replace steel in reinforced concreteand working to create a foundation forstrength gradingthat could encourage development of the building standards and codes bamboo needs for wider adoption in larger construction projects.

Architects are also exploring how complex structures built primarily with bamboo might look and function inexpanding urban spaces.

Industry, NGOs partner to push bamboo as a construction material

Widuzis a bio-based materials startup established by researchers who were part of a seven-year collaboration between the Future Cities Laboratory, the Singapore National Research Foundation and ETH Zurich.Javadian,Widuz’ CEO, was part of that collaboration, which focused on testing the mechanical and physical properties of a proprietary engineered bamboo product, BVL, now sold byWiduz.

BVL is made up of 90% bamboo fibers and 10% bio-compatible binder. According toJavadian, the company’s testing of BVL showed that “it was possible to replace steel reinforcement in concrete for low-rise housing up to three or four stories.”Widuzhas built a prototype, two-story house using BVL-reinforced concrete and BVL walls and beams.

Widuzhas recently partnered with the nonprofit Smiling Gecko’sbamboo project. Smiling Gecko is based in Cambodia, a country with a history of bamboo vernacular construction and plentiful bamboo forests. It currently runs a primary school where bamboo netting is used underneath a clay tile roof to keep internal temperatures down.

Widuzwill be buildinga two-story secondary school using BVLfor Smiling Gecko. The startup is setting up its first factory on Smiling Gecko property in Cambodia as well, as part of the organizations’ long-term partnership.

Hannes Schmid, photographer and founder of Smiling Gecko, said that the nonprofit organization will also host a laboratory to continue bamboo research with universities. Schmid said that Cambodia “is growing and the people want room; they want houses.Sowe urgently need alternative materials. There’s no other way around. But there’s so many different types of bamboo and only a few that have the stability to replace steel.”

Building industry confidence in bamboo

There are more than 1,500 bamboo species and even more subspecies. Only a few have potential as any sort of structural construction material. The range of variables in researchers’ testing and documentation regarding bamboo’s potential as a construction material complicate the adoption of building standards and codes.

Building in Cambodia is possible because local regulations only require that full designs be submitted to local architects and structural engineers for approval. The lack of construction standards and building codes for bamboo and engineered bamboo are barriers to wider commercialization. Without building standards and codes, architects and engineers will be reluctant to specify bamboo in their plans despite its clear environmental advantages and aesthetic qualities.

“More support is needed from the industries to put in the energy and work with governmental agencies and certification agencies to make engineered bamboo available under building codes,”Javadiansaid.