Advantages and Limitations of Seismic Isolation

Under many circumstances, seismic isolation is an effective way of reducing the impact of earthquakes on structures. Dynamic forces in the structure itself are reduced at the expense of relatively large displacements in the isolators. These displacements can generally be predicted adequately by simple methods and accommodated without difficulty. However, some circumstances appear to exist where the isolator displacements might be significantly larger than conventional analysis would suggest, or where simplified methods of analysis may prove inadequate and fail to predict the response properly. The paper explores the limits of the applicability of equivalent linear analyses and the response to ground motions which might lead to large displacements isolation that can be achieved.