Progressive collapse resistance of single-layer latticed domes subjected to non-uniform snow loads

Abstract

Catastrophic progressive collapse of long-span spatial structures subjected to non-uniform snow loads is often reported; however, few studies have been performed in this field. In the present study, progressive collapse tests of a scaled single-layer latticed K6 dome subjected to the non-uniform load were conducted. The failure mode, dynamic response, and collapse mechanism of the tested dome were examined. After the FE model was validated, the effects of the degrees and distributions of non-uniformity and rise-to-span ratios on the progressive collapse resistance under non-uniform loads were examined by a series of full-scale models. The results indicate that the failure mode of the tested dome subjected to the non-uniform load is a global collapse. The members connected to the failed joint and other members demonstrate the beam and compression mechanisms, respectively. For K6 domes, under the same mean loading condition (the change of snow height due to wind), the higher non-uniform degree causes a bigger structural response and leads to a lower collapse resistance; under the same maximum loading condition (snow melts locally due to temperature), although the maximum load has not changed and the total load is smaller, the non-uniform load can still result in unfavorable collapse for domes when the maximum load increases to a certain value, meaning that a dome is also dangerous when snow melts locally. Domes are most prone to collapse when the load is distributed non-uniformly along the ring direction (the settlement of snow accumulation), followed by the load distributed non-uniformly about radial members (the change of wind direction). Additionally, a dome with a smaller rise-to-span ratio under non-uniform loads collapses earlier.