A 1/100 scale model of a double-layer space truss designed for a long-span retractable roof was loaded statically. Its rise-span ratio is about 0.20 and members were made of cupper pipes. Single chord tests showed that the elasto-plastic axial force could be obtained from experimental strains. Results of elasto-plastic buckling analyses were well-agreed with experimental ones. At the overall-model test, coupled chord bucklings were observed and they caused a general instability. Buckling length of a chord in a rigid-jointed truss can be approximated as that of coupled buckling of two chords, when elasto-plastic chord bucklings precede to others.
