Newly proposed analytical estimating equations for the constant-ductility residual displacement ratio spectra of inelastic superstructures achieve reasonable accuracy when compared to statistical mean values, according to a parametric study by Lianglong Song, Xuan Su, and Tong Guo published in Earthquake Engineering and Engineering Vibration. The constant-ductility residual displacement ratio, denoted as Cr, can be used to predict residual displacement demands within displacement-based seismic design for building structures, addressing an absence of reliable analytical expressions that incorporate soil-structure interaction effects.
To investigate the behavior of superstructures within soil-structure interaction systems, the researchers established an analytical model combining structural and geotechnical elements. The superstructure was modeled using a bilinear elastoplastic single-degree-of-freedom oscillator, while the underlying soil was simulated through the cone model to account for interaction mechanisms between the ground and the building.
The constant-ductility spectra were established using results derived from nonlinear time-history analyses of the coupled soil-structure interaction systems. In these numerical simulations, the models were subjected to dynamic excitation from a collection of earthquake ground motions to evaluate inelastic structural demands under varying seismic conditions.
Statistical analysis results were subsequently employed to examine how multiple system parameters influence both the mean values of Cr and their dispersions. The evaluated parameters included the displacement ductility ratio, superstructure period, structure-to-soil stiffness ratio, aspect ratio, and the post-yield stiffness ratio of the superstructure. Using nonlinear multivariable regression analysis across these variables, the authors formulated the analytical estimating equations for the mean Cr spectra, confirming their predictive accuracy against statistical results.
Subject of Research: Constant-ductility residual displacement ratio spectra in soil-structure interaction systems
Article Title: Constant-ductility residual displacement ratio spectra of inelastic structures considering soil-structure interaction
Article References: Song, L., Su, X., & Guo, T. (2026). Constant-ductility residual displacement ratio spectra of inelastic structures considering soil-structure interaction. Earthquake Engineering and Engineering Vibration, 25(4), 951-962. https://doi.org/10.1007/s11803-026-2414-0
Image Credits: AI Generated
DOI: 10.1007/s11803-026-2414-0
Keywords: earthquake engineering, soil-structure interaction, residual displacement ratio, inelastic structures, seismic design, multivariable regression analysis, cone model, structural vibration, Constant-ductility, residual, displacement, ratio
News Source: Denise Maddox. (November 6, 2026). Estimating Equations Model Residual Displacement Spectra Considering Soil-Structure Interaction. Scienmag.
