Evaluation of Structure Frequency on the Dynamic Response of Piled Raft Foundations

Articles in Press

Document Type : Regular Paper

Authors

1 Master’s Graduted of Geotechnical Engineering, Iran University of Science and Technology (IUST), Narmak, Iran

2 Assistant Professor, School of Engineering, Damghan University, Damghan, Iran

3 Professor, School of Civil Engineering, Iran University of Science and Technology (IUST), Narmak, Iran

4 Associate Professor, School of Civil Engineering, Iran University of Science and Technology (IUST), Narmak, Iran

Abstract

This study examines the impact of structural frequency under various input excitations on the dynamic behavior of a piled raft (PR) foundation embedded in a dry sand layer. Numerical modeling using the finite element method was evaluated by experimental results from centrifuge test. The findings reveal that the structure's natural frequency, affected by the dynamic characteristics of both the soil and the foundation, is significantly lower than that of the fixed-base condition. However, the structure's frequency changes are independent of the excitation dominant frequency. Furthermore, as the structure's natural frequency rises, the disparity between the fixed-base condition and the foundation-inclusive scenario becomes increasingly pronounced. These changes significantly affect the whole dynamic system responses, precisely the maximum bending moment along the piles. It highlights the importance of considering the soil-structure interaction in the design process. Additionally, when the frequency of the input excitation closely aligns with the system's natural frequency, it induces the most significant dynamic responses in the soil, pile, raft, and structure. Consequently, relying solely on fixed-based methods in design can lead to unrealistic and potentially unsafe technical decisions.

Highlights

  • Abaqus 3D is an effective tool for simulating soil-structure interaction.
  • The system's frequency plays a crucial role in the dynamic response of both the foundation and the structure.
  • Modifying the structural frequency at a constant height significantly impacts the pile moments.

Keywords

Main Subjects

Journal of Rehabilitation in Civil Engineering

Articles in Press, Accepted Manuscript
Available Online from 07 January 2025

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History

  • Receive Date: 31 August 2024
  • Revise Date: 08 December 2024
  • Accept Date: 06 January 2025

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