In the summer of 2012, four organizations gathered to make possible yet another structure made out of cane (ESFA-InvestigacioCanyera, Sustenta, Canyaviva and the yet incipient Alitura). The project was developed within the research effort of all four groups in order to obtain a mechanical characterization of the Arundo Donax as a building material.
- Density = Specific mass = mass per unit volume: 40 Kg/m3
- Young’s modulus: 250.000 N/mm2
- Section area: 3.000 mm2
- Moment of inertia: 2.500.000 mm4
There are many others, mostly depending on the software one chooses, but what matters is that, in the used abstraction for this particular and simple case (called Timoshenko Beam), the only really important information used is that above.
Density (specific mass) and Young’s modulus were estimated iteratively, modifying their values in the program until the calculated displacements were somewhere near reasonable. A further more accurate measure of the specific mass of a bundle of cane and of the displacements in the structure will be in order and soon published.
Regarding the element sections, a CAD software was used to calculate the values from a general section of a bundle. From the past experiments made (see an article on the topic in ACE journal: http://www.consultorsestructures.org/images/stories/quaderns/Quaderns_estructures_46_baixa.pdf) it is still unclear whether the inertia of the bundle or its Young’s modulus is reduced about the middle of the arch.
Future research efforts should be oriented towards simplifying these assumptions but most importantly towards a methodology for obtaining these values in the field with some acceptable accuracy and speed.