One of the targets in the design of large-span structure is to minimize the weight. Based on this point, a new type of single-layer lattice shell consisted of aluminum members and joints has been developed and examined by authors since 1989. This single-layer lattice shell has insertion joint system which shows semi-rigid characteristic for the bending moment. In order to grasp the structural behaviours of the lattice shell, the following reseaches have been planed and performed : (1) Experiment of structural elements such as member and joint, (2) Experiment of small-scale models. In the first part, the tensile, compressive and bending tests for structural elements are shown in order to examine the stiffness and the ultimate strength. In the second part, the structural behaviour of four kinds of small-scale models with a diameter of 4.2 meters are examined under an uniform load and an concentrated load in the center part. For all models, torsional instability of node occurs because the bending rigidly in the in-plane direction is weaker. In the third part, exparimental results are presented and evaluated in detail.
