Effect of processing methods on the mechanical properties of engineered bamboo

Engineered bamboo is increasingly explored as a material with significant potential for structural applications. The material is comprised of raw bamboo processed into a laminated composite. Commercial methods vary due to the current primary use as an architectural surface material, with processing used to achieve different colours in the material. The present work investigates the effect of two types of processing methods, bleaching and caramelisation, to determine the effect on the mechanical properties. A comparison to other engineered bamboo and timber products is also presented. The results of the study indicate that processing does affect the mechanical properties of engineered bamboo products. Areas in need of further research are also identified for thermally treated bamboo to be used in structural applications.The presented work is supported by EPRSC Grant EP/K023403/1, and forms part of a collaboration between the University of Cambridge, Massachusetts Institute of Technology (MIT) and University of British Columbia (UBC).This is the final published version. It first appeared at http://www.sciencedirect.com/science/article/pii/S0950061815001956

Engineered bamboo for structural applications

Bamboo is a rapidly renewable material that has many applications in construction. Engineered bamboo products result from processing the raw bamboo culm into a laminated composite, similar to glue-laminated timber products. These products allow the material to be used in standardised sections and have less inherent variability than the natural material. The present work investigates the mechanical properties of two types of commercially available products – bamboo scrimber and laminated bamboo sheets – and compares these to timber and engineered timber products. It is shown that engineered bamboo products have properties that are comparable to or surpass that of timber and timber-based products. Potential limitations to use in structural design are also discussed. The study contributes to a growing body of research on engineered bamboo and presents areas in which further investigation is needed.The presented work is supported by EPRSC Grant EP/K023403/1 and the Newton Trust, and forms part of a collaboration between the University of Cambridge, Massachusetts Institute of Technology (MIT) and University of British Columbia (UBC).This is the published version. It was first published at http://www.sciencedirect.com/science/article/pii/S0950061815001117

Rwanda Cricket Stadium: Seismically stabilised tile vaults

The Rwanda Cricket Stadium, completed in 2017, uses compressed soil-cement tiles, thin-tile vaulting, and geogrid reinforcement for seismic stabilisation in Kigali’'s moderate risk earthquake zone. The vaults follow the natural resolution of forces toward the ground, closely mimicking the parabolic geometry of a bouncing ball and evoking the cherished hilly topography of Rwanda. The masonry vaults in compression allow the use of geogrid embedded within the mortar layers, adding global ductile behaviour to the thin shell composite of low strength tiles. Structural analysis is based on thrust lines, with additional envelope for the thrust lines to leave the profile of the masonry computed from the tensile capacity added by the geogrid (Ramage and Dejong [1]). Construction follows traditional thin-tile techniques adapted for new environments and uses compressed earth tiles as pioneered at the Mapungubwe Interpretive Centre in South Africa (Ramage et al. [2]). Here, the two approaches are combined in a permanent structure, with the largest vault spanning 16 m with a rise of 8 m. The Rwanda Cricket Stadium is a fusion of advanced structural analysis and architectural design with labour intensive, locally-sourced material production offering a much-needed solution to building sustainably in the developing world. Employing air-dried, hand-pressed soil tiles, produced using local labour, this method of construction has proved to be innovative, cost effective and beautiful

Flexible and sustainable building components through kerf patterns

Populations in cities are increasing, the way we live is changing, and climate change is at the forefront of the architectural agenda. There is an urgent need to develop sustainable and flexible spaces for future urban housing. This paper examines the potential for using engineered timber, a renewable material that stores carbon, for the production of flexible housing. The paper focuses on kerfing, a cutting method that can turn flat rigid panels into foldable or curved elements. This project aims to develop light and flexible folded partitions that address the challenges of affordability and sustainability for our future cities

Environmental Audit Committee Call for Evidence:"Sustainability of the Built Environment".

The Centre for Natural Material Innovation in the Department of Architecture at the University of Cambridge is a cross-disciplinary centre, bringing together people and research in plant sciences, biochemistry, chemistry, fluid dynamics, engineering, and architecture. Through innovative research and experimentation, we aim to transform the way we build to achieve zero carbon emissions. Our work enables the substitution of artificial materials such as concrete and steel with nature-based materials such as timber and bamboo, and replacement of structural carbon fibre and glass fibre with hemp and flax-based biocomposites. We collaborate with other leading research institutions globally, including in the USA, China, Australia, Uruguay and others

Climate repair through built environment: Decarbonising UK’s building sector through energy efficiency and natural materials

This working paper is an evidence submitted to the Royal Institution for British Architects that makes the case that the built environment must drastically reduce its carbon emissions to work towards net zero. Here we advocate for climate repair through the built environment by decarbonising UK’s building sector through both improved energy efficiency of buildings and the use of nature‐based solutions, such as engineered timber and natural insulating materials. The UK has the opportunity to lead by example at the upcoming United Nations COP‐26 conference and beyond as we implement the solutions in the coming years

Unfolding Timber - A future of design

"Unfolding” is a pavilion comprised of six lightweight structures designed for the London Design Biennale 2021. “UnFolding” examines the potential for using engineered timber with digital tools to produce flexible interiors. The pavilion is folded through kerfing methods into fractal-based structures. Extensive research, testing, and sample fabrication were accomplished for the project to acquire optimal flexibility of different timber members through kerf patterns

Experimental characterization of multi-full-culm bamboo to steel connections

The present research examines the performance of newly developed multi-full-culm bamboo to steel connections under monotonic axial loading. The culms are of Kao Jue (Bambusa pervariabilis) bamboo species. Findings reveal that the plain (unreinforced) connections fail early by undesirable brittle longitudinal splitting of bamboo culms. The confinement provided by hose-clamps inhibits this brittle failure mode, and with sufficient end-lengths, drastically increases the strength and ductility of the connection. Compared to the hollow-section connections with hose clamps, adding mortar infill further increases the strength. However, it also restricts bolt-deformation and thus diminishes the ductility. More importantly, the European Yield Model (which refers to dowelled timber connections) can analytically estimate the obtained experimental yield loads with satisfying accuracy. This is a promising direction towards a more rational and safer structural design of bamboo structures

Achieving zero carbon emissions in the construction sector: The role of timber in decarbonising building structures.

This research aims to evaluate a realistic timber adoption scenario as a way of reducing carbon emissions of construction in Chile and the UK for the period 2020-2050. The study finds that a gradual increase of timber construction could complement the emission reduction targets set by traditional materials, providing the needed carbon storage. This analysis shows the urgency to define the criteria that will allow to account for carbon storage in timber construction as a natural contribution to the Paris agreement. Finally, it is worth highlighting that the construction sector also faces several economic and social problems that need to be addressed urgently. Timber adoption would reduce emissions and at the same time improve health, security, gender gap, precision, speed and working conditions in construction