Abstract
There are several types of "SASUGUMI" (Japanese style roof truss) in traditional farmhouses at TOHOKU district. We analysised the mechanical property - rigidity - of 8types of "SASUGUMI" and reached the following 3 conclusions. (1) The rigidity of "SASUGUMI" is ruled by "SASU" (like a rafter-beam) and tie beam. (2) The types of "SASUGUMI" with collar (〓) are very effective against vertical load. (3) The types of "SASUGUMI" with "tsuka" (〓) are very effective against horizontal load. At the areas with many calamities of wind and earthquake, "SASUGUMI" had been transformed to the types with "tsuka" (〓), and at the snowy areas with many calamities of wind and earth-quake, "SASUGUMI" had been changed to the types combined collar (〓) with "tsuka" (〓). So, we have reached the conclusion that "SASUGUMI" had been transformed to adaptate the natural calamities.
