Soil-Structure Interaction for Integrated Design of Weakened and Damped Structures

Previous research has shown the effectiveness of the integrated design of weakening and damping techniques (WeD) for the seismic retrofitting of structures. Indeed, WeD techniques are able to reduce inter-story drifts and total accelerations, the two major performance measures to evaluate the seismic behavior of structures. Past research has been applied to fixed-based structures considering relatively stiff soil conditions. It has been suspected, though, that using such techniques in soft soil sites while considering soil structure interaction, may diminish some of the advantages observed in past research. This paper examines the effect of site conditions and soil-structure interaction on the seismic performance of Weakening and Damping techniques. An established rheological soil-shallow foundation-structure model with equivalent linear soil behavior and nonlinear behavior of the superstructure has been used. A large number of models incorporating wide range of soil, foundation and structural parameters were generated using robust Monte-Carlo simulation. The various structural models, along with the various site conditions, have been used for the comparative study. The design methodologies previously developed by the authors have been applied to each model considering different site conditions leading to the optimal weakening and damping. The results of the comparative study are used to quantify the effects of site conditions and foundation flexibility on the performance of the retrofitted structures.