In progress: a curved dome

from Daizen News  1 April 2012

We’re in the process of erecting a dome for a sun room in a house. Daizen is one of the few sources in B.C. that produces grain-matched, bent, structural timber on a regular basis. To do this, we have developed an entire system, including our proprietary heavy duty clamps.

There is a huge difference between bending a curve and a cut-out curve. Curved beams that are bent retain their continuous fibre, which is what’s required to withstand a compression and tension load. But cut-out timbers simply cut a shape out from a larger timber. This approach is not only limited in size; it can also disconnect most of the fibres entirely, eliminating its usefulness as structural timber. Also, a cut-out curve may split, especially if it is not cut out from free-of-heart-center (FOHC) timber, again limiting the size potential.

A curved beam truss, or a dome as in these pictures, is a structural member, feasible only by bending. In a setting of mostly right angles and straight lines, bent structural timber is not only functional—it’s also refreshing in its roundness.