concrete/steel mixed structures analysis considering soil-structure interaction

concrete/steel mixed structures analysis considering soil-structure interaction

identification of damping properties for a mixed structure and its interaction with underlying soil is a challenge for structural designers. current codes and available commercial software packages do not provide analytical solutions for such structural systems. due to irregular damping ratios, dynamic response of each part of a mixed structure differs significantly. in addition, when the structure is subjected to seismic loads the soil-structure interaction effects cannot be neglected. to manage these issues, engineers assumed to have an approximate uniform damping ratio of 2% and 5% for whole parts. this assumption results in errors between responses of the model and the structure. the present paper aims at contributing toward a better understanding of the error levels between the approximate and exact damping ratios. the obtained results show that the amount of error for soft soils is less than its amount for stiff soils, and the maximum error is obtained in the fixed- base model.