Earthquake response bound analysis of uncertain base-isolated buildings for robustness evaluation

An efficient methodology is presented to evaluate the robustness (variability of response) of an uncertain base-isolated building. While a basic assumption of "inclusion monotonic" is introduced in usual interval analysis, the possibility is taken into account of occurrence of the extreme value of the objective function in an inner feasible domain of the interval parameters. It is shown that the critical combination of the structural parameters can be derived explicitly so as to maximize the approximate objective function by 2nd-order Taylor series expansion. The URP (Updated Reference-Point) method is proposed to obtain such critical combination ofstructural parameters. In order to investigate the validity of the proposed robustness evaluation methodologies, numerical analyses are conducted for 20-storey base-isolated building models with natural rubber isolators and passive dampers. By comparing the results with the exact solution and those by other conventional methods, it is shown that the URP method can provide a more accurate evaluation of response bounds without hard computational effort.