Comparison of progressive collapse resistance of single-layer latticed domes under different loadings

Progressive collapse tests of two single-layer latticed Kiewitt domes were conducted in this paper. In each dome, one meridian member was suddenly removed and the full field structural responses, including high-speed 3D joint displacements and high-frequency member strains, were collected. Results of the test program and the corresponding FE analysis show that: (1) The tested dome under smaller loads regained balance easily, while a snap-through collapse occurred for dome under larger loads. Hence, although a single-layer latticed dome is normally constructed with hundreds of structural members, progressive collapse of the whole structure can be caused merely by the loss of a single critical member; moreover, load-resistance redundancy of a single-layer latticed dome is crucially important in resisting progressive collapse. (2) The sudden removal of a member caused a non-significant impact on the overall compressive membrane force flow but resulted in severe structural damage at the end-joints of the removed member; if the local damage was not properly absorbed, point buckling would occur on one of these two joints and was regarded as the immediate cause of the progressive collapse. (3) The collapse mode of a single-layer latticed dome subjected to sudden member-loss was characterized by a totally snap-through collapse; the collapse started from the point-buckling joint and was caused by successive downward movements of the surrounding joints. (4) Finite-element analysis provides an efficient way for progressive collapse study of dome structures, but fracture criterion of constructional steel that considers the complex stress states during progressive collapse is still needed.