A time‐domain seismic SSI analysis method for inelastic bridge structures through the use of a frequency‐dependent lumped parameter model

Abstract

SUMMARYIt is highlighted in the past that the soil-structure interaction phenomenon can produce a significant alteration on the response of a bridge structure. A variety of approaches has been developed in the past, which is capable of tackling the soil-structure interaction problem from different perspectives. The popular approach of a discretized truncated finite element model of the soil domain is not always a numerically viable solution, especially for computationally demanding simulations such as the probabilistic fragility analysis of a bridge structure or the real time hybrid simulation. This paper aims to develop a complete modeling procedure that is capable of coping with the soil-structure interaction problem of inelastic bridge structures through the use of a frequency dependent lumped parameter assembly. The proposed procedure encounters accuracy and global stability issues observed on past methods while maintaining the broad applicability of the method by any commercial FEM software. A case study of an overpass bridge structure under earthquake excitations is illustrated in order to verify the proposed method.

A parametric study on the axial behaviour of elastomeric isolators in multi-span bridges subjected to horizontal seismic excitations

“…A set of lumped parameter models (LPMs), as shown in Fig. 3b, is used to describe the soil-structure inertial interaction between the soil and the foundations (Makris et al 1994;Dezi et al 2013;Lesgidis et al 2015), as discussed more in detail in the next section. The Young's modulus of the reinforced concrete piers and of the deck is assumed equal to 30GPa.…”

Anti-symmetric mode excitation and seismic response of base-isolated bridges under asynchronous input motion

“…Given that the dynamic stiffness and damping at the soil-foundation interface are frequency-dependent, the mean period of each input motion was used for defining the spring and dashpot properties thus accounting for the dominant frequency of each ground motion used. More refined lumpedparameter models have also been developed by the authors [72][73][74] that match the target impedance function along the entire frequency range in the framework of response history analysis, however, this was deemed out of scope of the particular study. At the abutments, the deck was assumed pinned along the transverse direction and free to slide in the longitudinal one.…”

Proceedings of the Fifteenth International Conference on Civil, Structural and Environmental Engineering Computing

“…The Soil structure interaction phenomenon is implemented in this study according to the proposed LP modelling procedure in [16]. According to the procedure the overall soil -structure dynamic system is initially represented as an ODE system according to a selected finite discretization (eq .1).…”

“…A variety of approaches have been proposed in the past with differences in efficiency and applicability [11]- [15]. A complete LP modelling approach on the detailed SSI simulation of bridge structures has been proposed in [16], where the stability issues of past LP models have been effectively addressed. The proposed method has been also numerically verified with the direct FEM simulation of the structure-soil domain system through the case study of a concrete overpass bridge.…”

“…The current study investigates the influence of the frequency dependent foundation behaviour in the overall response of overpass bridges, through the comparison of the LP modelling procedure proposed in [16] and the conventional Kelvin-Voigt model method in the response of a reference bridge. The comparison is initiated through a general parametric study where the response divergence between the two methods relative to a number of different foundation and soil domain properties is thoroughly investigated.…”