Parameter identification for frame structures considering dynamic soil-structure-interaction

Four cases of experimental modal analyses, with variation of the number of stories, were conducted for a four-story reinforced concrete frame structure with independent footing under the columns. The hammer impulse method was employed to measure the global modal frequencies and the mode shapes of each case. Considering the dynamic interaction of the soil-base-structure, a shear-bending frame model is employed for the superstructure, and the simplified embedded square slab's impedance function proposed by Pais et al. is employed as for the infrastructure. Using the criterion that the foundation's dynamic shear modulus and story's elastic modulus will increase with the increase in stories, a multi-objective optimization criterion is formulated. A sensitivity method for under-determined problems, using frequencies, is employed to identify the physical parameters and foundation parameters simultaneously. The identified modes match well with the measured ones. The identified parameters can reflect the influence of foundation on the structure and provide the basis for damage identification.