Linear and Nonlinear Structure-Soil-Structure Interaction During Earthquakes

Abstract

This thesis aims to evaluate the effects of Structure-Soil-Structure Interaction (SSSI), by performing time-history seismic simulations, given different parameters of structures, inter-building spacings, and soil types. Different linear and nonlinear reduced-order models are generated and subjected to varied acceleration ground motions.
An extended 2D linear model that enables higher mode interaction between structures is proposed (Chapter 3). Results suggest that the coupled effects are possible between more than just the primary modes. Therefore, there is a significant interaction between a small building closely flanked by a much taller one.
Chapter 4 introduces a 2D model that examines the SSSI between unsymmetrical-plan and symmetrical-plan buildings. Results suggest that a taller torsionally-irregular building adjacent to smaller buildings could be adversely affected by SSSI. This contradicts previous studies, where the taller buildings benefit from adjacent smaller buildings.
Nonlinear soil behaviour is incorporated in the two-dimension model (Chapter 5) by employing Bouc-Wen’s model, for the soil underneath the foundations. The ground motion is spectrally matched with Eurocode-8 elastic spectra. Results show that the SSSI effects could be more pronounced when the nonlinear behaviour is considered.
Chapter 6 presents a 3D model of SSSI between multiple buildings which shortens computational run-times for large clusters. The auto-rotational and inter-rotational spring stiffnesses of foundations are determined by a surficial displacement field (based on Boussinesq approximation and calibrated against FEA) and inverse system identification (using least-squares or Kronecker products). Different building arrangements are presented to compare with previous research and highlight the method’s versatility.
Chapter 7 investigates the effects of the rotational ground motions upon buildings. Rotational ground components are extracted by using a multi-station procedure, and data from the SMART-1 array are employed. Results show that the rotational ground motion can amplify the responses of certain structures, depending on the ratio of rotational to horizontal ground motions.

Date of Award	21 Jan 2021
Original language	English
Awarding Institution	The University of Bristol
Sponsors	CONICYT, Becas Chile Programme
Supervisor	Nicholas A Alexander (Supervisor)