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Construction with Bamboo
Diplom-Ingenieur Christoph Tönges |
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Already several architects and engineers occupied themselves with the development of a useful connection of bamboo tubes and presented many different solutions, reaching from simple lashing and glueing techniques over combined solutions to complex connections, for example, injecting concrete and transferring forces through screws and steel tabs. |
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(78) Oscar Antonio Arce-Villalobos, 1993 | ||
To design a connection, that can take advantage particularly of the enormous
tensile strength of Guadua
it is inevitable to take a look at its
material properties
at first. The
fibers
of the outer third of a section of the bamboo culm wall are the most efficient.
So the goal is to introduce the forces into this part of the culm wall as
distributed as possible to avoid
axial splitting
of the bamboo material.
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(79) Diagonal section through Guadua | ||
After a thorough examination of existing connections and the qualities of
Guadua, I also wanted to execute some experiments.
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(80) I.C. David Trujillo Cheattle, 2001 | (81) J.J.A. Janssen, 1981 | ||
ad 1: A sheet metal with a certain order of holes serves as pattern to drill
holes for the screws and as a 'washer' for the screws at the same time. The
large amount of screws and their regular distribution should provide an good
power transmission to the bamboo cross section ie. to its hard outside skin.
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(82) Prototype 1, C. Tönges, 2002 | (83) Prototype 1 (without mortar) | ||
ad 2: The other idea is to cut the bamboo end axially crosswise to generate a cone by tightening a steel clamp. This cone is filled up with mortar as well. This cone should transfer the force to the outer high-tensile fibers. |
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(84) Slitting with a chainsaw | (85) Prototype 2, C. Tönges, 2002 | ||
Tests
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(86) Tests in Manizales | ||
ad 1: The mortar cylinder transferred the forces to the screws. With
increasing tensile load the screws were pressed into the bamboo
(approximately 0,5 cm) and twisted in direction of the force at the
same time. The end of the bamboo tube splitted. With further increase
of traction, the mortar broke.
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(87) Failure, prototype 1 | ||
ad 2: The mortar failed here, too. A cylindrical piece of mortar with the
diameter of the initial opening broke out of the connection. No measurable
distortion of the steel clamp nor splitting of the Guadua culms were observed.
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(88) Failure, prototype 2 | ||
Further development
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(169) Tetrahedron by 'Construction with Bamboo' | ||
Bibliography
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Links
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