Strand Woven Bamboo Finger Joints
High Strength Finger Joint usable in Strand Woven Bamboo of the 5th Generation
Bamboo is one of the fastest growing plants in the world which can be used as a building material, in its conventional round shape or engineered into laminated or composite plates and beams. Strand Woven Bamboo is such a composite, based on the principal of scrimber wood, developed in China mainly for replacing outdoor hardwood flooring boards. The last generation (5th) uses about 90% of the raw bamboo which makes it one of the best alternatives regarding land occupation for growing building materials. Important in respect to the expected upcoming land shortage and depletion of raw materials.
Due to the production process of SWB5G, all of the strong bamboo fibres are present in the finished product, an advantage when used in structural elements. However, the SWB5G beams and plates are limited in there sizes. For using this material in structural elements the plates need to be transformed into larger sized laminated Glulam beams, LSWB5G. The weak spots in these beams are the finger joints, the strongest finger joint attains about half the strength of the base material SWB5G. For exploiting the full potential of LSWB5G, a stronger finger joint is needed.
The main topic of this research is developing a high strength finger joint usable in LSWB5G which will approach the strength of the base material or even be stronger. SWB5G is relatively new with only a few properties known. Firstly the mechanical properties of SWB5G relevant for the finger joint needs to be investigated. Besides the base material SWB5G (adherent), the strength of a finger joint depends on the production, the used glue (adhesive) and the geometry of the finger joint. Although practicability is an important precondition, variations in production processes will not be included. Also, it is not the intention to develop a new adhesive system but rather to use one of the existing systems and eventually optimize it in regard to SWB5G and the geometry of the finger joint. Deducting the relation between the strength of the finger joint with the selected adhesive system and the geometry with its variations will be a large part of this study.