ABSTRACT
Abstract Results of a series of tests of 15 complete trusses with CHS members are summarized. Two of the trusses are space trusses with triangular cross sections. All the trusses were tested to failure by applying reversals of deflection for 1 to 3 cycles. The trusses showed diverse failure modes, which included buckling of members, failure of joints and combined member buckling and joint failure. Ductile cracks frequently developed and grew rapidly during a few cycles of reversed loading, which sometimes led to tensile rupture of joints or members. When failure of joints occurred before buckling of members, existing joint capacity formulae based on isolated joint tests were found to predict observed resistances of joints with good accuracy. However, after buckling of members, joints came under combined bending and axial loads as a result of stress redistribution and failed at a load lower than the capacity of joints under axial loads only. New design criteria for tubular joints to avoid occurrences of failure with insufficient ductility in trussed structures under the influence of strong earthquakes are proposed. Keywords: Truss, Circular tube, Tubular joint, Earthquake, Buckling, Ductile fracture, Shell bending.
