A robust probabilistic evaluation of soil-foundation-structure interaction effects on structural response

Evaluation of soil-foundation-structure interaction (SFSI) effects on structural response is a challenging task because of the involved impact of uncertainties in system’s parameters and randomness in the input earthquake motion. In this paper, a rational method is utilized to elucidate these effects through the use of a rheological soil-foundation-structure model in a robust probabilistic simulation. Realistic, but random models with varied soil and structural parameters within relevant range of values are generated out of a Monte Carlo simulation and subjected to an ensemble of earthquake motions. Both linear and nonlinear structural behavior due to earthquake motion is considered. The SFSI effects on linear structural response are quantified by the median response and the accompanied dispersion and are then used as a reference when evaluating the SFSI effects for superstructures with nonlinear behavior. In addition, for the structural systems with linear behavior detrimental SFSI scenarios are indentified. The achieved quantification of SFSI effects can be used as a significant step towards a reliable seismic design framework incorporating SFSI. Note that in all analyses the nonlinearity in soil behavior has been accounted for through the equivalent linear approach. structural nonlinearity in the SFSI problem was evaluated by comparing the median structural responses in linear and nonlinear structural systems. 2 PROBABILISTIC SIMULATIONS