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oa Civil Engineer in South Africa - Prediction of deformations of a deep excavation and tower block foundation : technical paper

 

Abstract

The basement and tower block for the proposed South African Transport Services computer centre and office block is to be constructed in Braamfontein in deeply weathered Ventersdorp lava. The new basement will be 26 m deep and the tower block will consist of 40 storeys above street level. The soil profile on the site consists of a residual soil up to a depth of approximately 57 m, whereafter soft rock occurs which gradually merges into unweathered rock with depth. The paper summarizes the predictions of the elasto-plastic movement of the basement boundaries due to the excavation and the recompression of the bottom of the excavation due to the tower block loading. A finite element method is used to predict the movements of four alternative methods of excavation support. The non-linear stress-strain properties of the weathered lava are used throughout. The usefulness of the finite element method of analysis for excavation and foundation design is shown. The soil-structure interaction is highlighted by the calculations, as well as the direct design applications for the building that follow from the results.

Die kelder en toringblok van die voorgestelde Suid-Afrikaanse Vervoerdienste Rekenaarsentrum en Kantoorblok word beplan om in Braamfontein in die diep verweerde Ventersdorp lawa gebou te word. Die nuwe kelder sal 26 m diep wees en die toringblok sal tot 40 vloere bo straatvlak strek. Die grondprofiel op die terrein bestaan uit residuele grond tot 'n diepte van ongeveer 57 m, waarna sagte rots voorkom wat geleidelik oorgaan in onverweerde rots met diepte. Hierdie referaat handel oor die voorspellings van die elasties-plastiese beweging van die sykante van die kelder weens die uitgrawing, asook die samedrukking van die uitgrawingsbodem weens die toringblokbelading. 'n Eindige elemente metode is gebruik om die bewegings van vier alternatiewe metodes van kelderstabilisering te voorspel. Die nie-liniêre spanning-vervorming eienskappe van die verweerde lawa is deurgaans in die berekeninge gebruik. Die nuttigheid van die eindige elemente metode van analise vir uitgrawing- en fondamentontwerp word aangedui. Die grond-struktuur interaksie se belangrikheid word deur die resultate beklemtoon asook die direkte ontwerptoepassings wat uit die resultate voortvloei.

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/content/civeng1/27/5/EJC24992
1985-05-01
2016-12-03
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