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Portrait of Amanda Oliveira against a technical drawing of a tower on an annular pile foundation.

PhD candidate · Dynamic soil-structure interaction

Amanda Oliveira

How do a structure, its foundation and dozens of piles move as one system?

Amanda develops unified models of flexible structures supported by interacting pile groups, including the transfer of energy through the soil.

  • IBEM-FEM
  • pile groups
  • contact
  • structural dynamics
An open braced structure on a pile cap, with embedded piles and qualitative waves in a dry-soil cutaway.
Conceptual illustration of dynamic soil-structure interaction. It depicts the research system, not a computed result.

The physical problem

A foundation does not move independently from the structure above it or the soil around it. In a large pile group, every pile influences the others through a three-dimensional wave field.

What the work is building

Her research couples flexible superstructures, arbitrary pile layouts, soil response and contact in one computational formulation. The work includes nonstandard geometries such as ring-shaped pile groups supporting tower-like structures.

Why it matters

More faithful coupling helps engineers identify when a simplified foundation model is adequate and when the interaction itself controls the response.

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Research evidence

Results and current work

Explore published studies, conference contributions and ongoing investigations.

Graphical abstract with labels 1–12: a wind-turbine tower, elastic soil, fixed-base and coupled FEM–BEM models, pile-soil-pile interaction, and three continuous vertical frequency-response curves. The teal coupled-model curve reaches its first resonance before the petroleum-blue fixed-pile-head and navy fully fixed-base curves. The numbered legend and graph guide explain the labels and axes.
Redrafted diagramThe dynamic response of a piled wind-turbine tower depends on foundation flexibility and energy transmitted through the soil between piles. The coupled model represents these effects; simplified fixed-support models shift the predicted resonances.
View full-size figure

Adapted from the graphical abstract and Figure 6 in Oliveira, A.; Vasconcelos, A. C. A.; Labaki, J. (2023), Latin American Journal of Solids and Structures, 20(6), e491. DOI: 10.1590/1679-78257514. Original article published under CC BY.

Peer reviewed

Dynamic response of piled structures including pile-soil-pile interaction

The receiving structure changes the vibration field rather than merely observing it. Increasing separation reduces transferred vibration, while structural height shifts the coupled resonances. Pile spacing cannot be reduced to one simple monotonic rule.

Graphical abstract key

  1. Wind-turbine tower: an example of a structure whose dynamic response depends on its supporting soil.
  2. Elastic soil: carries energy away from the structure as propagating waves, producing radiation damping.
  3. Rigid-base approximation: neglects soil and foundation flexibility and may misrepresent the dynamic response.
  4. Coupled soil-pile-structure model: the proposed formulation includes the dynamic behavior of the supporting soil.
  5. Finite element method (FEM): represents the elastic superstructure, illustrated by the mesh on the tower base.
  6. Boundary element method (BEM): represents the surrounding soil and its interaction with the piles; the piles themselves use finite beam elements.
  7. Pile-soil-pile interaction: energy passes between piles through the intervening soil, represented by the teal wave paths.
  8. Vertical frequency-response function: vertical displacement at the tower response point per unit vertical force, compared for three support assumptions.
  9. Coupled model, teal curve: includes flexible piles, soil response and interaction between piles (Case 3 in the paper).
  10. Fixed pile-head supports, petroleum-blue curve: only the discrete pile-head locations are fixed; soil interaction is omitted (Case 2).
  11. Fully fixed base, navy curve: the entire bottom surface is fixed; soil interaction is omitted (Case 1).
  12. First-resonance shift: the fully fixed-base model overestimates the first vertical natural frequency compared with the coupled model in this example.
How to read the graph

Horizontal axis: normalized excitation frequency a₀ = ωd/cₛ, from 0 to 3. Here ω is angular excitation frequency, d is pile diameter, and cₛ is the soil shear-wave speed. Vertical grid lines are spaced by 0.5 in a₀.

Vertical axis: magnitude of vertical displacement per unit vertical force, |u_zz| = |U_zz/F_z|, in m/N, on a logarithmic scale. The displayed range is 10⁻¹³ at the bottom to 10⁻⁸ at the top; successive horizontal grid lines differ by a factor of ten.

The drawings are schematic, not to scale; the depicted pile count and mesh are illustrative. The continuous curves were digitized from the unobscured amplitude panel of the published Figure 6, not recalculated from raw simulation data. Their colors follow the SSI Lab palette.

Open journal article

Dissertation

Dynamic interaction and energy transfer between piled structures

Amanda's MSc work established the coupled modelling basis that her PhD now extends toward flexible superstructures, arbitrary pile groups and richer contact conditions.

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