Abstract
This paper presents a three–dimensional linear numerical model for the dynamic and seismic analysis of pile-supported structures that allows to represent simultaneously the structures, pile foundations, soil profile and incident seismic waves and that, therefore, takes directly into account structure–pile–soil interaction. The use of advanced Green’s functions to model the dynamic behaviour of layered soils, not only leads to a very compact representation of the problem and a simplification in the preparation of the data files (no meshes are needed for the soil), but also allows to take into account arbitrarily complex soil profiles and problems with large numbers of elements. The seismic excitation is implemented as incident planar body waves (P or S) propagating through the layered soil from an infinitely–distant source and impinging on the site with any generic angle of incidence. The response of the system is evaluated in the frequency domain, and seismic results in time domain are then obtained using the frequency–domain method through the use of the Fast Fourier Transform. An application example using a pile-supported structure is presented in order to illustrate the capabilities of the model. Piles and columns are modelled through Timoshenko beam elements, and slabs, pile caps and shear walls are modelled using shell finite elements, so that the real flexibility of all elements can be rigorously taken into account. This example is also used to explore the influence of soil profile and angle of incidence on different variables of interest in earthquake engineering.
Highlights
In order to illustrate the capabilities of the model described above, this section presents results corresponding to the seismic response of a pile-supported building founded on a stratified soil and subjected to different earthquakes generated by trains of S-waves that impinge the site vertically or with a certain angle of incidence
It is worth noting that the boundary element (BE)–FE code considers rigid slabs, with inertial properties lumped at the slab geometrical centres, while the proposed
A new model for the dynamic and seismic analysis of pile-supported buildings including structure–foundation–soil interaction, seismic incident waves and the possibility of modelling complex soil profiles without an excessive increase in computational effort has been presented in this paper
Summary
The dynamic response of pile foundations and pile-supported structures has been an important subject of study during several decades (see e.g. Kaynia (1982); Kaynia and Kausel (1991); Miura et al (1994); Mylonakis and Gazetas (1999); Blaney and El Naggar (2000); Nikolaou et al (2001); Maeso et al (2005); Escoffier et al (2008); Rovithis et al (2013); Goit et al (2013); Dowling et al (2016); Li et al (2016); Carbonari et al (April 2019); Ha et al (2019) Chatterjee et al (2019); Correia and Pecker (2021)) due to the widespread use of deep foundations and the influence that the dynamic soil–pile–structure interaction (SSI) phenomena can exert on the dynamic and seismic response of the structures (see e.g. Veletsos and Meek (1974); Mylonakis and Nikolaou (1997); Gazetas and Mylonakis (1998); Mylonakis and Gazetas (2000); Stewart et al (1999a, 1999b); Gerolymos et al (2008); Medina et al (2013); Di Laora and de Sanctis (2013); Pitilakis et al (2014); Medina et al (2015); de Sanctis et al (2015); Sun and Xie (2019)). The significant increase in terms of computational effort and memory usage needed to model a large number of layers, or the difficulty to represent continuously varying soil properties, are significant disadvantages that limit the applicability of the boundary element method to some problems, unless specific advanced fundamental solutions are employed to model layered soils without the need of discretizing the layer interfaces For this reason, Álamo et al (2016) proposed a numerical model for pile foundations in which, by employing advanced Green’s functions for modelling the dynamic response of the layered unbounded viscoelastic soil medium together with a Timoshenko beam formulation for modelling the dynamic response of piles, the integral equations that describe the dynamic behaviour of the soil-foundation system are significantly simplified and produce a very compact numerical approach for the problem. The coupling between the superstructure and pile elements is made by imposing compatibility (in terms of nodal displacements and rotations) and equilibrium (through pile-structure coupling forces) conditions, and the solution of the whole coupled system can be found from the resolution of a linear system of equations involving only unknowns related to piles and structures (Sect. 2.4)
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