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Using small-strain stiffness to predict the settlement of shallow foundations on sand
Dissertation (MEng)--University of Pretoria, 2014.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2015
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| _version_ | 1867613565398024192 |
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| access_status_str | Open Access |
| author2 | Heymann, Gerhard |
| author_browse | Heymann, Gerhard |
| author_facet | Heymann, Gerhard |
| collection | Thesis |
| dc_rights_str_mv | © 2014 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MEng)--University of Pretoria, 2014. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/43358 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:38:09.710Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2015 |
| publishDateRange | 2015 |
| publishDateSort | 2015 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/43358 Using small-strain stiffness to predict the settlement of shallow foundations on sand Heymann, Gerhard fieliesarcher@gmail.com Archer, Andre UCTD Dissertation (MEng)--University of Pretoria, 2014. Settlement prediction of shallow foundations is an essential part for the design of a structure. Accuracy is important, and to increase the accuracy, reliable input parameters are required. However, reliable input parameters do not necessarily render accurate results since the parameters used in design are only as good as the prediction method. Foundation design on sands consists of two aspects: bearing capacity and settlement, with settlement being the governing factor in almost all cases. Settlement prediction is not always an easy task. The main reason being that engineers are unable to measure stiffness accurately as well as how to use the stiffness value measured in certain settlement methods. An important soil stiffness value is the initial small-strain shear modulus (G0) which can be obtained relatively easy with in-situ test methods and the values obtained are generally reliable. With in-situ testing becoming increasingly popular, settlement prediction methods utilising the initial small-strain shear stiffness are also becoming more common. The main objective of this project is to determine whether the load-settlement behaviour of a shallow foundation can be estimated accurately using only the small-strain shear modulus of the granular soil below the foundation. Centrifuge tests were conducted on an equivalent 5m circular shallow foundation at three different density sands to establish if the stress-settlement behaviour can be predicted and to what level of accuracy. The different density sands were loose, medium dense and dense sands. Bender- and extender elements were used to determine the small-strain stiffness data which were used for the analysis. The main conclusion drawn from the study is divided into two parts; Full-range load-settlement behaviour and Practical-range load-settlement behaviour. The full-range results relate to full stress-settlement curve with the practical-scale results up to settlements of 0.1D. The method proposed for the load-settlement prediction is a non-linear stepwise method. The proposed method requires utilising a stiffness degradation curve and it was found that curves presented by Oztoprak & Bolton (2013) and Bolton & Whittle (1999) produced the best results. For the full-range load-settlement results, accurate predictions were found between the predicted and measured load-settlement curves for low density sand. However accuracy decreases with increase in density. For settlements up to 0.1D the load-settlement behaviour was predicted with reasonably good accuracy. The study showed that the settlement of a shallow foundation can be predicted with reasonable accuracy up to 0.1D settlement using only the small-strain shear stiffness value of the soil below the foundation and that there is merit in the proposed method for future use. lk2014 Civil Engineering MEng Unrestricted 2015-01-19T12:13:34Z 2015-01-19T12:13:34Z 2014/12/12 2014 Dissertation Archer, A 2014, Using small-strain stiffness to predict the settlement of shallow foundations on sand, MEng Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/43358> M14/9/410 http://hdl.handle.net/2263/43358 en © 2014 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Using small-strain stiffness to predict the settlement of shallow foundations on sand |
| title | Using small-strain stiffness to predict the settlement of shallow foundations on sand |
| title_full | Using small-strain stiffness to predict the settlement of shallow foundations on sand |
| title_fullStr | Using small-strain stiffness to predict the settlement of shallow foundations on sand |
| title_full_unstemmed | Using small-strain stiffness to predict the settlement of shallow foundations on sand |
| title_short | Using small-strain stiffness to predict the settlement of shallow foundations on sand |
| title_sort | using small strain stiffness to predict the settlement of shallow foundations on sand |
| topic | UCTD |
| url | http://hdl.handle.net/2263/43358 |