An improved replacement oscillator approach for soil-structure interaction analysis considering soft soils

This paper aims to improve the effectiveness of the replacement oscillator approach for soil-structure interaction (SSI) analysis of flexible-base structures on soft soil deposits. The replacement oscillator approach transforms a flexible-base single-degree-of-freedom (SDOF) structure into an equiva...

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Main Authors: Lu, Yang, Hajirasouliha, Iman, Marshall, Alec M.
Format: Article
Published: Elsevier 2018
Subjects:
Online Access:https://eprints.nottingham.ac.uk/51074/
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author Lu, Yang
Hajirasouliha, Iman
Marshall, Alec M.
author_facet Lu, Yang
Hajirasouliha, Iman
Marshall, Alec M.
author_sort Lu, Yang
building Nottingham Research Data Repository
collection Online Access
description This paper aims to improve the effectiveness of the replacement oscillator approach for soil-structure interaction (SSI) analysis of flexible-base structures on soft soil deposits. The replacement oscillator approach transforms a flexible-base single-degree-of-freedom (SDOF) structure into an equivalent fixed-base SDOF (EFSDOF) oscillator so that response spectra for fixed-base structures can be used directly for SSI systems. A sway-rocking SSI model is used as a baseline for assessment of the performance of EFSDOF oscillators. Both elastic and constant-ductility response spectra are studied under 20 horizontal ground motion records on soft soil profiles. The effects of frequency content of the ground motions and initial damping of the SSI systems are investigated. It is concluded that absolute acceleration spectra, instead of pseudo-acceleration spectra, should be used for EFSDOF oscillators in force-based design of SSI systems. It is also shown that using an EFSDOF oscillator is not appropriate for predicting the constant-ductility spectra when the initial damping ratio of the SSI system exceeds 10%. Based on the results of this study, a correction factor is suggested to improve the accuracy of the replacement oscillator approach for soft soil conditions.
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spelling nottingham-510742020-05-04T19:46:21Z https://eprints.nottingham.ac.uk/51074/ An improved replacement oscillator approach for soil-structure interaction analysis considering soft soils Lu, Yang Hajirasouliha, Iman Marshall, Alec M. This paper aims to improve the effectiveness of the replacement oscillator approach for soil-structure interaction (SSI) analysis of flexible-base structures on soft soil deposits. The replacement oscillator approach transforms a flexible-base single-degree-of-freedom (SDOF) structure into an equivalent fixed-base SDOF (EFSDOF) oscillator so that response spectra for fixed-base structures can be used directly for SSI systems. A sway-rocking SSI model is used as a baseline for assessment of the performance of EFSDOF oscillators. Both elastic and constant-ductility response spectra are studied under 20 horizontal ground motion records on soft soil profiles. The effects of frequency content of the ground motions and initial damping of the SSI systems are investigated. It is concluded that absolute acceleration spectra, instead of pseudo-acceleration spectra, should be used for EFSDOF oscillators in force-based design of SSI systems. It is also shown that using an EFSDOF oscillator is not appropriate for predicting the constant-ductility spectra when the initial damping ratio of the SSI system exceeds 10%. Based on the results of this study, a correction factor is suggested to improve the accuracy of the replacement oscillator approach for soft soil conditions. Elsevier 2018-07-15 Article PeerReviewed Lu, Yang, Hajirasouliha, Iman and Marshall, Alec M. (2018) An improved replacement oscillator approach for soil-structure interaction analysis considering soft soils. Engineering Structures, 167 . pp. 26-38. ISSN 0141-0296 Soil-structure interaction; Soft soil; Seismic design; Replacement oscillator; Nonlinear analysis https://www.sciencedirect.com/science/article/pii/S0141029617330298 doi:10.1016/j.engstruct.2018.04.005 doi:10.1016/j.engstruct.2018.04.005
spellingShingle Soil-structure interaction; Soft soil; Seismic design; Replacement oscillator; Nonlinear analysis
Lu, Yang
Hajirasouliha, Iman
Marshall, Alec M.
An improved replacement oscillator approach for soil-structure interaction analysis considering soft soils
title An improved replacement oscillator approach for soil-structure interaction analysis considering soft soils
title_full An improved replacement oscillator approach for soil-structure interaction analysis considering soft soils
title_fullStr An improved replacement oscillator approach for soil-structure interaction analysis considering soft soils
title_full_unstemmed An improved replacement oscillator approach for soil-structure interaction analysis considering soft soils
title_short An improved replacement oscillator approach for soil-structure interaction analysis considering soft soils
title_sort improved replacement oscillator approach for soil-structure interaction analysis considering soft soils
topic Soil-structure interaction; Soft soil; Seismic design; Replacement oscillator; Nonlinear analysis
url https://eprints.nottingham.ac.uk/51074/
https://eprints.nottingham.ac.uk/51074/
https://eprints.nottingham.ac.uk/51074/