Seismic Performance of Structures Isolated with FPS for Different Soil Conditions considering Intermediate Isolation Degrees

FOLINO, P.; CASTALDO, P.; RIPANI, M.

Pistoia

Congreso; L'Ingegneria sismica in Italia - ANIDIS 2017 - XVII Convegno; 2017

Italian National Association of Earthquake Engineering

This study investigatesthe optimal properties of friction pendulum devices to seismically isolateelastic structural systems under earthquake excitations having differentcharacteristics in terms of frequency content considering intermediateisolation degree values. A two-degree-of-freedom model is considered todescribe the isolated system behavior with a velocity-dependent model for theisolators. Specifically, a non-dimensional formulation of the governingequations of motion is adopted assuming the superstructure displacements, theisolator forces and damping factors as the response parameters of interest forthe performance assessment. Several seismic artificial excitations, havingfrequency contents properly defined to describe respectively stiff, medium andsoft soil conditions, are assumed. Finally, the optimum values of the frictioncoefficient that minimize the superstructure displacements as a function of thestructural system properties, of the intermediate isolation degree values andof the soil condition are numerically computed.