Sökning: "Anders Ansell"

Visar resultat 6 - 10 av 27 avhandlingar innehållade orden Anders Ansell.

  1. 6. Models for analysis of shotcrete on rock exposed to blasting

    Författare :Lamis Ahmed; Anders Ansell; Erik Nordström; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Shotcrete; Rock; Vibration; Stress waves; Numerical analysis.; Sprutbetong; Berg; Vibrationer; Spänningsvågor; Numerisk analys.;

    Sammanfattning : In underground construction and tunnelling, the strive for a more time-efficient construction process naturally focuses on the possibilities of reducing the times of waiting between stages of construction. The ability to project shotcrete (sprayed concrete) on a rock surface at an early stage after blasting is vital to the safety during construction and function of e. LÄS MER

  2. 7. Models for analysis of young cast and sprayed concrete subjected to impact-type loads

    Författare :Lamis Ahmed; Anders Ansell; Richard Malm; Lennart Elfgren; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Young concrete · Shotcrete · Rock · Impact-type vibration · Finite element method · Fracture mechanics model · Crack width;

    Sammanfattning : The strive for a time-efficient construction process naturally put focus on the possibility of reducing the time of waiting between stages of construction, thereby minimizing the construction cost. If recently placed concrete, cast or sprayed, is exposed to impact vibrations at an early age while still in the process of hardening, damage that threatens the function of the hard concrete may occur. LÄS MER

  3. 8. Time dependent material properties of shotcrete for hard rock tunnelling

    Författare :Lars Elof Bryne; Anders Ansell; Wolfgang Kusterle; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Shotcrete; rock; granite; bond strength; compressive strength; pullout testing; failure modes; interfacial transition zone; micro structure; ettringite; set accelerator; shrinkage; drains; glass fibres; laboratory testing; tunnels tunnelling;

    Sammanfattning : In this thesis different mechanical properties for shotcrete (sprayed concrete) such as compression strength, bond strength, bending tensile strength, elastic modulus, free and restrained shrinkage as a function of its age was investigated. One of the main issues was to investigate the difference between ordinary cast concrete and shotcrete. LÄS MER

  4. 9. Toward Realistic Failure Evaluations for Concrete Buttress Dams

    Författare :Jonas Enzell; Anders Ansell; Erik Nordström; Andreas Sjölander; Richard Malm; Leif Lia; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; concrete dams; buttress dams; stability analysis; dam failure behavior; physical model tests; FEM; betongdammar; lamelldammar; stabilitetsanalys; dammbrott; fysiska modellförsök; FEM; Betongbyggnad; Concrete Structures;

    Sammanfattning : Concrete dams, complex structures supporting massive loads, have traditionally been assessed using simplified 2D analytical stability analyses based on the rigid body assumption. Previous studies have shown that 3D behavior, such as the interaction between the monoliths and the valley's geology, can greatly impact the load-bearing capacity of gravity dams but remains largely unexplored in buttress dams. LÄS MER

  5. 10. Multiphase models for freeze-thaw actions and mass transport in concrete hydraulic structures

    Författare :Daniel Eriksson; Anders Ansell; Richard Malm; Erik Nordström; Stefan Jacobsen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Degradation; Hydraulic structures; Air-entrained concrete; Multiphase models; Multiphysics; Long-term moisture conditions; Freeze-thaw; Hysteresis; Absorption; Calcium leaching; Finite Element Method; Concrete Structures; Betongbyggnad;

    Sammanfattning : A crucial task for civil engineers is to make appropriate designs of new concrete structures and assessments of existing structures to ensure a long service life and sustainable use of the infrastructure. This doctoral thesis aims to increase the understanding of how advanced mathematical models can be used to describe phenomena and processes governing concrete degradation and thereby ultimately contribute to improving tools for design and assessments. LÄS MER