Bamboo Structure #1

This is the first post in a series on the structure of bamboo and some of the advantages and challenges we face in using it for bicycle construction.

If you are building a bicycle frame, what do you want out of the material?

You want it to be strong. You want it to be smooth riding. You want it to be light. You want it to be durable. You want it to be environmentally friendly. And, you want it be easy to use in fabrication.
Bamboo hits all of these, and the reasons are in its structure.

Bamboo is a composite material, similar to rebar-reinforced concrete or fiberglass-epoxy boat hulls. These are fiber-matrix composites, in which forces are transmitted between fibers by the matrix (glue or concrete).
Bamboo consists of ultra strong vascular bundles known as power fibers, set in a woody, foamy matrix called lignin, encased in a hard skin. In the cross section above, the power fibers are the dark dots, and the lignin is the lighter part.

Bamboo fibers are extremely strong in tension. According to some engineering studies they are as strong as steel. These power fibers are set in a stiff tubular shape by the woody matrix. The tubular composite structure allows bamboo to be both light and strong, efficiently using the minimum of dense power fibers creates a strong structure.

Bamboo is very similar in structure to a carbon tube, but grows straight out of ground…