Experimental and numerical study on the influence of dynamic structure-soil-structure interaction on the responses of two adjacent idealized structural systems

To investigate the influence of dynamic structure-soil-structure interaction (SSSI) on the responses of two adjacent structures, shaking table tests were conducted on a series of scaled soilstructure interaction (SSI) systems and SSSI systems, where the influence of structure size, structure spacing and seismic records on SSSI was considered. To further investigate the SSSI effect, a three-dimensional finite element model accounting for SSI effect was presented and its reliability was validated through testing results, based on which numerical parametric analyses of SSSI effect were conducted. It is found from testing results that compared with SSI, the SSSI effect on peak accelerations at the top of structure specimens ranged from -19% to 8% and the maximum effect of SSSI on structural frequency was about 5% when the soil shear wave velocity was 120 m/s. Besides, regarding the acceleration at the bottom of concerned structure, the Fourier amplitudes and pseudo accelerations at the frequencies near the natural frequency of adjacent structure can be significantly changed by the SSSI. The change of local ground motion caused by adjacent structure is the main reason for the change of base shear for the concerned structure. In addition, in general, the SSSI effect on structural responses decreases with larger structure spacing, and the SSSI effect on structural seismic demands may increase or reduce with the increase of structure size and the change of seismic excitation direction.