Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Steel fibre reinforced concrete (SFRC) is the most prominent fibre reinforced concrete composite
that was engineered to enhance the material’s post-cracking behaviour. In certain situations it is
utilised to replace conventional reinforcement and considered to be more cost-efficient.
The purpose of this research is to characterise the moment redistribution behaviour of a statically
indeterminate SFRC structure with varying volumes of fibres, with the focus on the development of
the moment redistribution accompanied by the rotation of the plastic hinges at the critical sections
in the structure.
The material properties were characterised with a series of experimental tests. The compression
behaviour was obtained with uniaxial compression tests while the uniaxial tensile behaviour was
obtained with an inverse analysis performed according to flexural test results. These properties were
utilised to derive a theoretical moment-curvature relation for each SFRC member which supplied the
basis for the characterised moment-rotation behaviour and the finite element analyses (FEA)
performed on the statically indeterminate structure. Experimental tests were conducted on the
statically indeterminate structure in laboratory conditions to validate the theoretical findings.
For the different SFRCs the material properties in compression were similar, while it resulted in an
increased tensile resistance with an increase in the volume steel fibres. The theoretical momentcurvature
and moment-rotation responses also indicated an increased structural capacity and
member ductility with an increase in the volume fibres.
From the finite element analyses the computational moment redistribution-plastic rotation relations
were obtained. It was found that the final amount of moment redistribution decreased with an
increase in the fibre volume, but that the rotational capacity increased.
It was found that the experimental moment-curvature and moment-rotation results correlate well
with the theoretical predictions. Also, unexpected structural behaviour was observed, but the issue
was addressed with applicable computational analyses which confirmed the possible causes. It was
concluded that the computational moment redistribution approximations were reasonably accurate.
A parameter study indicated that the crack band width differed among the different SFRC members. / AFRIKAANSE OPSOMMING: Staal vesel versterkte beton (SVVB) is die mees vooraanstaande vesel versterkte beton mengsel wat
ontwikkel is om die materiaalgedrag na kraakvorming te verbeter. In sekere situasies kan dit gebruik
word om konvensionele staal te vervang en lei soms to koste vermindering .
Die einddoel van die studie is om die moment herverdeling gedrag te karaktiseer vir ‘n statiese
onpebaalbare SVVB struktuur deur die invloed van verskillende volumes vesels en die rotasie
kapasiteit by die kritieke posisies in ag te neem.
Die materiaal eienskappe was geidentifiseer met ‘n reeks eksperimentele toetse. Die druk gedrag
was geïdentifiseer deur eenassige druktoetse, terwyl die eenassige trek gedrag bekom is met die
implementasie van ‘n inverse analise van die uitgevoerde buig toetse. Hierdie eienskappe is gebruik
om die teoretise moment-kromming verhouding vir elke mengsel te bekom. Hierdie verhoudings
word as die basis bestempel vir die teoretiese moment-rotasie verhouding en die eindige element
analises (EEA) wat op ‘n staties onbepaalbare struktuur toegepas is. Eksperimentele toetse is op
hierdie voorgestelde struktuur toegepas om die teoretiese verwagtings te verifieer.
Dit is gevind dat die druk gedrag ooreenstem tussen die verskillende mengsels, alhoewel ‘n toename
in die trek kapasiteit ervaar is met ‘n toename in die volume vesels. Die teoretiese momentkromming
en moment-rotasie verwantskappe stel ook voor dat die strukturele kapasiteit en
duktiliteit toeneem met ‘n toename in die volume vesels.
Die teoretiese moment herverdeling-plastiese rotasie verwantskapppe is verkry deur middel van die
eindige element analises. Dit is gevind dat die aantal moment herverdeling by faling afgeneem het
vir ‘n toename in die volume vesels, maar dat dit to ‘n groter rotasie kapasiteit gelei het.
Van die eksperimentele resultate is dit afgelei dat die teoretiese moment-kromming en momentrotasie
verwantskappe goeie benaderings voorstel. Sekere invloede van die opstelling het daartoe
gelei dat onverwagte strukturele gedrag bekom is, maar die moontlike invloede is verifieer met
eindige element analises. Dit is afgelei dat die teoretiese beramings van die moment herverdeling
gedrag redelik akkuraat is. ‘n Parameter studie het getoon dat die kraak spasiëring verskil tussen
mengsels met verskillende volumes vesels.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/20250 |
| Date | 03 1900 |
| Creators | Mohr, Arno Wilhelm |
| Contributors | Boshoff, W. P., Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 173 p. : ill. |
| Rights | Stellenbosch University |
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