Abstract
The present paper aims at developing a new design method for steel roof structures to cover large spans. At present, convienient and temporary structures for covering large scale roofs are plane lattice trusses or space frames. As a method contrary to this, we develop a new design method of structures using long beams constituted with three dimensional trusses in one direction. The members constituting the truss beams are steel tubes. In this paper, we discuss the dynamic properties of the three dimensional truss beams which will be necessary for designing and make it clear by analysis and experiments. These properties are proved to be well explained by continuous theory.
