Sökning: "Richard Malm"

Visar resultat 1 - 5 av 19 avhandlingar innehållade orden Richard Malm.

1. 1. Predicting shear type crack initiation and growth in concrete with non-linear finite element method

   Författare :Richard Malm; Håkan Sundquist; Anders Ansell; Kent Gylltoft; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; non-linear finte element analysis; concrete; crack width; crack propagation; shear; Building engineering; Byggnadsteknik;

   Sammanfattning :   In this thesis, the possibility to numerically describing the behaviour that signifies shear type cracking in concrete is studied. Different means for describing cracking are evaluated where both methods proposed in design codes based on experiments and advanced finite element analyses with a non-linear material description are evaluated. LÄS MER

3. 2. Shear cracks in concrete structures subjected to in-plane stresses

   Författare :Richard Malm; Håkan Sundquist; Kent Gylltoft; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Shear; plane state stress; crack width; FE analysis; design standards; serviceability state; Civil engineering and architecture; Samhällsbyggnadsteknik och arkitektur;

   Sammanfattning : After only two years of service, extensive cracking was found in the webs of two light-rail commuter line bridges in Stockholm, the Gröndal and Alvik bridges. Due to this incident it was found necessary to study the means available for analysing shear cracking in concrete structures subjected to in-plane stresses. LÄS MER

4. 3. Numerical modelling considerations for analysis of concrete hydraulic structures subjected to high-frequency seismic loads

   Författare :Roghayeh Abbasiverki; Anders Ansell; Erik Nordström; Richard Malm; Peter Folkow; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Betongbyggnad; Concrete Structures;

   Sammanfattning : Concrete hydraulic structures are of great importance in today's society. When situated in areas with hard bedrock, these structures may become extra vulnerable to seismic excitations as these here are dominated by high-frequency vibrations which can have disastrous consequences for slender structures. LÄS MER

5. 4. 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

7. 5. 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