Study of the unified strength theory for seismic response of frame building on loess considering soil-structure interaction

To investigate the effect of soil-structure interaction (SSI) on the seismic response of frame buildings on collapsible loess, the secondary development of Abaqus was used to realize the embedding of the unified strength theory constitutive model. Meanwhile, a new nonlinear elastic model generated by the unified strength theory (b, the failure criterion parameter in the unified strength theory, equals 0.5) was developed. Seven- and nine-story frame buildings were selected as engineering examples in this study. The outcomes indicate that the nonlinear behavior of the loess-pile has a significant effect on the dynamic interaction of both group pile foundations and the superstructure under strong earthquakes. This results in an amplification of the displacement response and a reduction in inter-story shear force. As the foundation soil becomes softer, the K-type distribution of both peak accelerations and inter-story displacements along height becomes more obvious in general.