Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: In regions of moderate seismicity it has been shown that a suitable structural system is
created when designing the shear wall with a plastic hinge zone at the lower part of the
wall, with the shear walls resisting lateral loads and all other structural elements
designed to resist gravity loads. A suitably stiff foundation is required for the
assumption of plastic hinge zones to hold true. This foundation should have limited
rotation and should remain elastic when lateral loads are applied to the structure.
Ensuring a foundation with a greater capacity than the shear wall results in excessively
large shear wall foundations being required in areas of moderate seismicity for
buildings with no basement level.
This study aims to investigate the feasibility of reducing the size of shear wall
foundations in areas of moderate seismicity for buildings with no basement level. The
investigation is aimed at allowing shear wall foundation rocking and taking into account
the contribution of structural frames to the lateral stiffness of the structure. An example
building was chosen to investigate this possibility.
Firstly, lateral force-displacement capacities were determined for a shear wall and an
internal reinforced concrete frame of this investigated building. Nonlinear momentrotation
behaviour was determined for the wall foundation size that would traditionally
be required as well as for six other smaller foundations.
The above capacity curves against lateral loads were then used to compile a simplified
model of the structural systems assumed to contribute to the lateral stiffness of the
building. This simplified model therefore combined the effect of the shear wall, internal
frame and wall foundation.
Nonlinear time-history analyses were performed on this simplified model to investigate
the dynamic response of the structure with different wall foundation sizes. By assessing
response results on a global and local scale, it was observed that significantly smaller
shear wall foundations are possible when allowing foundation rocking and taking into
account the contribution of other structural elements to the lateral stiffness of the
building. / AFRIKAANSE OPSOMMING: Daar is reeds getoon dat ʼn voldoende strukturele sisteem verkry word in gebiede van
gematigde seismiese risiko indien ʼn skuifmuur ontwerp word met ʼn plastiese skarnier
sone naby die ondersteuning van die muur. Skuifmure word dan ontwerp om weerstand
te bied teen laterale kragte met alle ander strukturele elemente ontwerp om gravitasie
kragte te weerstaan. Vir die aanname van plastiese skarnier sones om geldig te wees
word ʼn fondasie met voldoende styfheid benodig. Só ʼn fondasie moet beperkte rotasie
toelaat en moet elasties bly wanneer laterale kragte aan die struktuur aangewend word.
ʼn Fondasie met ʼn groter kapasiteit as dié van die skuifmuur lei daartoe dat uitermate
groot fondasies benodig word in gebiede van gematigde seismiese risiko vir geboue met
geen kelder vlak.
Hierdie studie is daarop gemik om die moontlikheid van kleiner skuifmuur fondasies te
ondersoek vir geboue met geen kelder vlak in gebiede van gematigde seismiese risiko.
Die ondersoek het ten doel om skuifmuur fondasie wieg aksie toe te laat en die bydrae
van strukturele rame tot die laterale styfheid van die struktuur in ag te neem.
Eerstens is die laterale krag-verplasing kapasiteit van ʼn skuifmuur en ʼn interne
gewapende beton raam van die gekose gebou bepaal. Nie-lineêre moment-rotasie
gedrag is bepaal vir die skuifmuur fondasie grootte wat tradisioneel benodig sou word
asook vir ses ander kleiner fondasie grotes.
Die bogenoemde kapasiteit kurwes is gebruik om ʼn vereenvoudigde model van die
strukturele sisteme wat aanvaar word om laterale styfheid tot die gebou te verleen, op te
stel. Hierdie vereenvoudigde model kombineer gevolglik die effek van die skuifmuur,
interne raam en skuifmuur fondasie.
Nie-lineêre tydgeskiedenis analises is uitgevoer op die vereenvoudigde model ten einde
die dinamiese reaksie van die struktuur te ondersoek vir verskillende fondasie grotes.
Resultate is beoordeel op ʼn globale en lokale vlak. Daar is waargeneem dat aansienlik
kleiner skuifmuur fondasies moontlik is deur wieg aksie van die fondasie toe te laat en
die bydrae van ander strukturele elemente tot die laterale styfheid van die gebou in ag te
neem.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/1957 |
| Date | 12 1900 |
| Creators | Van der Merwe, Johann Eduard |
| Contributors | Wium, J. A., University of Stellenbosch. Faculty of Engineering. Dept. of Civil Engineering. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | Unknown |
| Type | Thesis |
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