Seismic behavior of tensegrity barrel vaults

Abstract

Tensegrity systems are spatial reticular systems in a state of self-stress. These systems are structures made up of an assembly of pin-jointed pre-stressed continuous tension members (cables) and discontinuous compressive members (struts), arranged in different complex shapes. Their stiffness is the result of a self stress that stabilizes infinitesimal mechanisms. Despite many studies on the seismic behavior of the space structures, so far a few investigations have been carried out to examine seismic behavior of these structures. Pioneers have suggested tensegrity systems as earthquake-resistant structures; nevertheless, this statement may be examined through extensive studies of the seismic behavior of tensegrity systems. In the present study, the seismic behavior of tensegrity barrel vaults has been investigated by carrying out linear and nonlinear analysis. All of the analyses have been undertaken using ANSYS package. Having verified the finite element modeling, eigenvalue and time history analysis have been undertaken in order to examine the seismic behavior of the tensegrity barrel vaults. Also, the effect of the rise to span ratio of these systems and influence of the self-stress level, have been investigated. Similar to reticular double layer barrel vaults, the dominant period of tensegrity barrel vaults increases with increase of rise to span ratio. As another result, it is shown that larger initial strains produce smaller natural periods. For selected models of tensegrity barrel vaults, horizontal accelerograms cause some cables yield or bars to buckle. However, vertical accelerograms are not so effective. Under horizontal component of earthquake, displacements grow with increase of rise to span ratio, while it is inverse under vertical accelerograms.