Progressive collapse demolition of double-layer space truss under different demolition load conditions

•Two double-layer space trusses (DLSTs) were tested under different external loads.•Structural responses and collapse phenomena of the tested DLSTs were monitored.•Commonalities in internal force redistribution of the tested DLSTs were discussed.•Load-carrying mechanisms of the tested DLSTs were analysed.•Collapse causations and characteristics of the two tested DLSTs were analysed. Two double-layer space trusses (DLSTs) under different demolition load conditions were tested for progressive collapse demolition. The primary load-carrying members of the tested DLSTs were removed one by one according to a pre-designed demolition process. The global structural responses, including the strains of the members on the main force transmission paths and the vertical displacements of representative joints, were measured. The structures' internal force redistributions and load-carrying mechanisms were investigated based on the experimental results and the corresponding FE analysis. The results show that both the tested DLSTs achieved progressive collapse demolition as expected. The two tested DLSTs under different demolition load conditions followed the same internal force redistribution patterns and exhibited three identical mechanical characteristics: arch action, catenary action, and beam action. The removal of specific members will change the load-carrying mechanism of the DLST and lead to local or global collapse.