Base Isolation of Sliding-Rocking Non-Symmetyric Rigid Blocks Subjected to Impulsive and Seismic Excitations

We analyse the influence of base isolation on the behaviour of rigid blocks representing works of art. The work of art has been modelled with a non-symmetrical rigid body, sitting on a base which is connected to a visco–elastic device which represents the passive control system. Both rocking and sliding motions have been considered. To prevent isolation device from breaking, security stops have been introduced which limit the displacement of the oscillating base to a maximum safe value. Two collapse mechanisms have been considered: collapse due to the fall from the oscillating base, and one due to the overturning of the rigid block. Several analyses have been carried out comparing the behaviour of non-isolated and isolated non-symmetric rigid body under impulsive and seismic excitations. The analysis focuses mainly on the effects of the friction coefficient, but the effects due to eccentricity of the rigid body, the presence of the security stops and other parameters have also been analyzed. The analysis reveals that base isolation can be more effective for rigid bodies with geometrical parameters similar to those of real works of art.