A thermodynamic-based macroelement approach for dynamic analysis of soil-structure systems

Nonlinear dynamic analysis is becoming a routinary approach for assessing the seismic performance of structures, especially in the case of soil-structure systems with marked nonlinear features or in earthquake prone regions. In these cases, the conventional sub-structure approach, based on linearity, loses its effectiveness. On the other hand, a fully coupled modelling cannot be considered as a suitable analysis method for extensive studies or in standard design. A compromise is therefore proposed: an approach with macroelements simulating the combined frequency- and amplitude-dependent response of geotechnical systems in the time-domain analysis of structures, preserving a limited computational effort. The thermodynamic inertial macroelements (TIMs) describe the multiaxial force-displacement relationships of the geotechnical systems, such as bridge abutments, shallow, deep and caisson foundations. These models are implemented in OpenSees as a new class of multiaxial materials, that ca...