Abstract: Seismic analysis is an essential procedure to design a structure subjected to ground motion. However, throughout conventional seismic analysis, the structure is subjected to a limited number of recorded earthquake excitations. Moreover, the presence of variations and uncertainties in the recorded excitations within a single, and among different earthquakes is not considered in current seismic analysis procedures. One methods of quantifying the impreciseness and uncertainty is the interval or unknown-but-bounded representation. In this work, a new computationally feasible method for seismic structural analysis with interval uncertainty in the response spectrum is developed, which is capable of obtaining the bounds on the structure’s dynamic response. Using this method, first, the response spectra from various recorded earthquakes are combined in order to construct an interval function referred to as an interval response spectrum. Then, the response spectrum analysis is performed using the developed interval response spectrum, and the bounds of the dynamic response of the structure are obtained. This computationally feasible method shows that calculating the bounds on the dynamic response does not require an iterative procedure such as Monte-Carlo simulation. Numerical example problems, which illustrate the developed algorithm, are presented, along with a comparison of solutions obtained by Monte-Carlo simulation.
