The design of modern buildings increasingly requires the assessment of ground-borne noise and vibration. This remains a challenging task, requiring estimates of structural vibration levels, the anticipated human response, and often the assessment of potential mitigation measures. The latter include base-isolation, in which a building is constructed on isolation bearings to reduce the transmitted vibration. Despite innovations in the bearings themselves, it is not yet clear how best to evaluate the performance of these base-isolated buildings. This paper presents a new analysis framework for evaluating base-isolation performance. The aim is to provide a rigorous but efficient methodology for the practicing engineer, based on a staged approach that begins with the expected free-field vibration levels and uses a series of simplified models to account for the "added foundation" and "added building" effects associated with the construction of a new building. The methodology can be used to inform the design of a base-isolated building based on "relative" measures of isolation performance.
