A frequency‐dependent and intensity‐dependent macroelement for reduced order seismic analysis of soil‐structure interacting systems

• Published in: Earthquake engineering & structural dynamics Vol. 47; no. 11; pp. 2172 - 2194
• Main Authors: Lesgidis, Nikolaos, Sextos, Anastasios, Kwon, Oh‐Sung
• Format: Journal Article
• Language: English
• Published: Bognor Regis Wiley Subscription Services, Inc 01.09.2018
• Subjects: Bridge foundations; Bridges; Civil engineering; Computational efficiency; Computer applications; Computer simulation; Dependence; Dynamical systems; Earthquakes; Evaluation; Finite element method; Frameworks; Ground motion; lumped parameter model; macroelement; Mathematical models; model order reduction; Model reduction; Modelling; Multiple objective analysis; Nonlinear analysis; Seismic activity; Seismic analysis; Seismic design; Seismic engineering; Seismic response; Soil; Soil analysis; Soil dynamics; Soil structure; soil‐structure interaction
• ISSN: 0098-8847; 1096-9845
• DOI: 10.1002/eqe.3063

Summary The computational demand of the soil‐structure interaction analysis for the design and assessment of structures, as well as for the evaluation of their life‐cycle cost and risk exposure, has led the civil engineering community to the development of a variety of methods toward the model order reduction of the coupled soil‐structure dynamic system in earthquake regions. Different approaches have been proposed in the past as computationally efficient alternatives to the conventional finite element model simulation of the complete soil‐structure domain, such as the nonlinear lumped spring, the macroelement method, and the substructure partition method. Yet no approach was capable of capturing simultaneously the frequency‐dependent dynamic properties along with the nonlinear behavior of the condensed segment of the overall soil‐structure system under strong earthquake ground motion, thus generating an imbalance between the modeling refinement achieved for the soil and the structure. To this end, a dual frequency‐dependent and intensity‐dependent expansion of the lumped parameter modeling method is proposed in the current paper, materialized through a multiobjective algorithm, capable of closely approximating the behavior of the nonlinear dynamic system of the condensed segment. This is essentially the extension of an established methodology, also developed by the authors, in the inelastic domain. The efficiency of the proposed methodology is validated for the case of a bridge foundation system, wherein the seismic response is comparatively assessed for both the proposed method and the detailed finite element model. The above expansion is deemed a computationally efficient and reliable method for simultaneously considering the frequency and amplitude dependence of soil‐foundation systems in the framework of nonlinear seismic analysis of soil‐structure interaction systems.