ブレースで補剛された単層直交格子ドームの座屈耐力に関する研究

摘要

The present paper proposes an effective method to evaluate elasto-plastic buckling loads of two-way single-layer lattice domes, stiffened by diagonal braces, under vertical uniform and non-uniform loads. The domes are shallow and composed of grid chord members, connected rigidly at nodes, and supported by pins at four sides of rectangular plan. First, a formula for linear buckling load is derived based on equivalent shell analogy, followed by a study for a knockdown factor of elastic buckling loads considering geometrical initial imperfections of a magnitude up to L_0/1000 for a span La. The value of 0.65 or a lesser value for a knockdown factor is recommended for use to evaluate elastic buckling loads. Second, column strength curves are discussed and proposed for elasto-plastic buckling loads, and finally, the proposed strength curves are proven effective for evaluating the strength.%弾性ブレースで補剛された単層直交格子ドームについて，FEM解析により線形座屈荷重，弾性座屈荷重および弾塑性座屈荷重（耐力）を求めるとともに，それらの荷重の推定方法を検討した。ただし，格子材は剛按，荷重は等分布荷重ならびに2種類の偏載荷重，形状はスパンが約60mで偏平，形状初期不整が一次座屈モード比例型でスパンの1000分の1以下，部材細長比が20から120，また，補剛ブレースの断面積の割合は格子材の0.10，0.15，0.20と限られた条件の範囲のものである。