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ThesisReykjavík University>Tækni- og verkfræðideild>MSc verkefni>

Please use this identifier to cite or link to this item: http://hdl.handle.net/1946/6882

Title

Concrete walls founded on earthquake areas

Published
June 2010
Abstracts
  • Calculations made by structural engineers of structural models are almost fixed to the ground (cantilever), even though in reality, the structures are founded on bedrock or soil bed. In the project, 10 walls are modeled in a structural software program, five squat walls and five slender walls. The walls have different foundations, fixed to the ground (cantilever), founded on bedrock and founded on soil bed (gravel) with and without damping. Earthquake load react under all walls, i.e. time history analysis. The main object of this project is to show how different foundations change the behavior of walls during seismic activity. The analysis of this behavior requires models that take into account not only the structure, but also the bedrock, soil bed and the dynamic interaction forces existing between them. The wall and support were modeled using finite element method (FEM) and boundary element method (BEM). The calculations were carried out using the software ANSYS. The soil-structure interaction (SSI), model was separated into near-field and far-field using FEM to represent the near-field, and viscous dampeners placed around the FEM model as boundary elements to represent the far-field. The results show that the effects of rocking the walls changes their behavior profoundly; displacements increased while the stress and shear forces diminished. A careful estimate would be that walls on bedrock are 25% less reinforced than fixed walls, and the walls on gravel bed are 50% less reinforced than fixed walls.

  • is

    Yfirleitt eru reiknilíkön mannvirkja höfð innspennt við jörð, til þess að gera útreikninga einfaldari, en í raunveruleikanum sitja mannvirkin laus á klöpp eða jarðvegi. Í verkefninu eru steyptir veggir greindir í burðarþolsforriti, bæði lágir veggir (squat) og háir veggir (slender). Greiningin felst í því að veggirnir eru grundaðir á klöpp, fyllingu og innspenntir (fastir við jörð). Jarðskjálftaálag er svo látið verka undir veggina, þ.e. tímaraðagreining. Markmið verkefnisins er að greina muninn á þessum mismunandi grundunum. Niðurstöður sýna að áhrif þess að hafa veggjamódel laus á undirstöðu, eykur færslu, á meðan spennur minnka sem og skerkraftar. Varlega má áætla, samanborið við innspennta veggi, þurfi 25% minni járnbendingu þegar veggir eru á klöpp og 50% minni járnbendingu þegar veggir eru á fyllingu (jarðvegi).

Comments
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Byggingarverkfræði

Issued Date
02/11/2010


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