Dynamic nonlinear analysis and assessment of structures with friction base isolation devices

The present work illustrates a dynamic nonlinear analysis of structures characterized by plan irregularity and base isolated by friction devices. Base isolation systems with friction pendulums are analysed to properly regularize the dynamic nonlinear behaviour of structures. Different isolation solutions with friction pendulums are investigated to optimize and regularize the dynamic nonlinear behaviour of structures with irregularities in plan. The nonlinear behaviour of the base-isolated structure is investigated when subject to representative dynamic events. Criteria for regularizing the dynamic behaviour of plan irregular structures are presented. The beneficial effects are illustrated for the adopted optimized isolation solution of friction pendulum system. The nonlinear behaviour of the isolation devices is determined as well as the nonlinear dynamic behaviour of the irregular in plan structure. A comparative dynamic nonlinear analysis is presented for the structure base isolated by the adopted solution of friction isolation system and the corresponding fixed base structure. In the comparative analysis, recorded accelerograms associated with dynamic events are considered and the nonlinear hysteretic cycles of isolation devices are presented, along with the time history of the base acceleration, the base shear, the base displacement and the inter-storey drifts of the structure.