A nonlinear constitutive model for beam elements with cyclic degradation and damage assessment for advanced dynamic analyses of geotechnical problems. Part II: validation and application to a dynamic soil–structure interaction problem

Abstract

The variation of the stiffness mismatch between soil and structural elements during ground motions is one of the most influential parameters for the assessment of the kinematic component in SSI problems. The variation of the stiffness ratio is mainly governed by material nonlinearity that can develop in either the soil or the structural parts of the system. The direct approach, which is in principle capable of accounting for both soil and structural nonlinearities, provides the “complete solution” to the SSI problem. The implementation of this approach requires the availability of general-purpose computational platforms where the modeling process is very often, particularly time-demanding. Even when using this kind of software, the substructure approach, suitable only if the system behave linearly or weakly nonlinearly, is often preferred over the direct method because it allows to split the model in two parts, simplifying the problem. The nonlinear constitutive model for beam elements presented in the companion paper (Andreotti and Lai in Bull Earthq Eng, 2017, doi:10.1007/s10518-017-0090-1) is conceived to be embedded in computer programs oriented to geotechnical applications to overcome their typical limitations in structural modeling. The proposed constitutive model is capable to simulate the cyclic degradation of stiffness and strength. Furthermore it allows to assess the damage experienced by the structure. Coupling the inelasticity of structural elements with the highly nonlinear behaviour of soils in a computer program specialized for geotechnical applications might hopefully contribute to bridging the gap between geotechnical and structural community when attempting to solve problems of soil–structure interaction. This paper presents the implementation, validation and application of the model to solve a dynamic soil–structure interaction problem by coupling the nonlinear behaviour of ground with the inelasticity of the structural elements.