STUDY OF PELLEVATION GEOMETRY EFFECTS ON IMPROVING SEISMIC PERFORMANCE OF SINGLE LAYER DIAMATIC DOMES

Among dierent types of space frame, the dome holds a special position because of its structural stability. Since changes in geometry play a key role in the structural response of space frames, in this paper, the efiects of applied pellevation with difierent geometry on improving the seismic performance of single layer diamatic domes are studied. For this purpose, one group, including simple single layer diamatic domes with dierent ratios of rise to span, has been created, and then, in another three groups, difierent types of pellevation are applied to the first group. Each group contains five models, and the defined groups have been generated in such a way that difierent possible geometries have been covered.
In formex algebra, during the pellevation process, a geometric object is used to deform a part of the given con- figuration by pushing the object upwards. In this paper, barrel pellevation, which can be easily matched to diamatic domes, is applied via implementing the BAPLE function. The computer program, Formian, is used as a tool to configure the pellevated single layer diamatic domes.
The nonlinear dynamic time history analysis is performed for the defined models, and the structural behaviors of the dierent systems are compared with each other via frequencies and mode shapes. For non-linear time history dynamic analysis, three scaled ground motion records appropriate to the design hazard levels of the Iranian Seismic Code have been selected.
Checking overall stability shows that dome de ection is the dominant design criteria, and, fortunately, it is possible to decrease the seismic de ection of diamatic domes via a change in geometry by applying proper pellevation" The results show the desirable efiects on the weight reduction of pellevated domes. Structural performance has been improved, such as the weight of the dome can be reduced by about 16% via choosing proper pellevation.