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## Analiza numeryczna mechanizmów zniszczenia w ścianach murowych

### Piotr Bilko

#### Abstract

Numerical Analysis of Failure Mechanisms in Masonry Walls The development of methods for evaluation of the effort and exhaustion of the load bearing capacity of masonry structures is stimulated by the need to preserve former infrastructure and adapt it to new functions; another stimulating factor is the growth of modern construction solutions, which employ new materials and technologies for erecting masonry structures. More and more attention is paid to the issues of effort and failure of masonry structures in complex stress states. Furthermore, analyses of the bearing capacity of masonry structures are more frequently performed with the aid of state-of-the-art numerical methods, mainly methods of finite elements. Progress is being achieved in both constitutive modelling of masonry structures and in numerical implementations of their models. The objective of this dissertation has been to assess the load bearing capacity based on a macroscopic model of a masonry, with a two-surface, orthotopic plasticity condition, with degradation of resistance parameters defining compression and tension strengths. Attention was drawn to the possibility of reproducing mechanisms causing damage and to the character of the stress distribution in the ultimate limit state. Examples of numerical modelling of the damage to masonry structures are given. Particular emphasis is laid on the implementation of own constitutive models in the commercial finite element code, using the so-called user defined subroutines. The applied constitutive relations based on a new class of effort criteria used for orthotopic materials, and have been implemented as own constitutive models in a commercial system of numerical calculations. Models with one or two yield surfaces have been presented with hemitropic amplification, both with a linear and non-linear degradation function. Constitutive modelling was supported by tests carried out in a system of symbolic calculations and in the finite element program. A series of numerical single-element tests was run to verify the appropriateness of implementations, which demonstrated potential reproducibility of the non-linear behaviour of material in different stress and strain states. The numerical tests were carried out in both a plane and a spatial stress state. The selected masonry models were verified in exemplary tests of damage of masonry structure. Numerical examples were used to analyze with macroscopic models masonry walls submitted to compression, bending and shearing in their plane. In addition to this, examples of analysis of a masonry infill in a ferroconcrete frame were also presented, in which different constitutive relationships for the mortar and brick material were adopted. Interface elements were also introduced. Finally, based on own laboratory studies, the compression strength of a wall was assessed with the help of the theory of reliability.
Record ID
WUT53bea9c0b3ef4fda8b13c0842048623e
Diploma type
Doctor of Philosophy
Author
Piotr Bilko Piotr Bilko,, The Institute of Civil Engineering (FCE/ICE)Faculty of Civil Engineering (FCE)
Title in Polish
Analiza numeryczna mechanizmów zniszczenia w ścianach murowych
Language
(pl) Polish
Certifying Unit
Faculty of Civil Engineering (FCE)
Discipline
construction / (technology domain) / (technological sciences)
Status
Finished
Defense Date
04-04-2014
Title date
16-04-2014
Supervisor
Leszek Małyszko Leszek Małyszko,, Undefined Affiliation
Internal reviewers
Wiesław Jan Wojewódzki Wiesław Jan Wojewódzki,, The Institute of Civil Engineering (FCE/ICE)Faculty of Civil Engineering (FCE)
External reviewers
Andrzej Winnicki Andrzej Winnicki,, Politechnika Krakowska ()
Pages
184
Keywords in English
masonry structures, constitutive modelling, plasticity, orthotrophy, failure criteria, finite element
Abstract in English
Numerical Analysis of Failure Mechanisms in Masonry Walls The development of methods for evaluation of the effort and exhaustion of the load bearing capacity of masonry structures is stimulated by the need to preserve former infrastructure and adapt it to new functions; another stimulating factor is the growth of modern construction solutions, which employ new materials and technologies for erecting masonry structures. More and more attention is paid to the issues of effort and failure of masonry structures in complex stress states. Furthermore, analyses of the bearing capacity of masonry structures are more frequently performed with the aid of state-of-the-art numerical methods, mainly methods of finite elements. Progress is being achieved in both constitutive modelling of masonry structures and in numerical implementations of their models. The objective of this dissertation has been to assess the load bearing capacity based on a macroscopic model of a masonry, with a two-surface, orthotopic plasticity condition, with degradation of resistance parameters defining compression and tension strengths. Attention was drawn to the possibility of reproducing mechanisms causing damage and to the character of the stress distribution in the ultimate limit state. Examples of numerical modelling of the damage to masonry structures are given. Particular emphasis is laid on the implementation of own constitutive models in the commercial finite element code, using the so-called user defined subroutines. The applied constitutive relations based on a new class of effort criteria used for orthotopic materials, and have been implemented as own constitutive models in a commercial system of numerical calculations. Models with one or two yield surfaces have been presented with hemitropic amplification, both with a linear and non-linear degradation function. Constitutive modelling was supported by tests carried out in a system of symbolic calculations and in the finite element program. A series of numerical single-element tests was run to verify the appropriateness of implementations, which demonstrated potential reproducibility of the non-linear behaviour of material in different stress and strain states. The numerical tests were carried out in both a plane and a spatial stress state. The selected masonry models were verified in exemplary tests of damage of masonry structure. Numerical examples were used to analyze with macroscopic models masonry walls submitted to compression, bending and shearing in their plane. In addition to this, examples of analysis of a masonry infill in a ferroconcrete frame were also presented, in which different constitutive relationships for the mortar and brick material were adopted. Interface elements were also introduced. Finally, based on own laboratory studies, the compression strength of a wall was assessed with the help of the theory of reliability.
Thesis file
• File: 1
Bilko.pdf
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Citation count
2

Uniform Resource Identifier
https://repo.pw.edu.pl/info/phd/WUT53bea9c0b3ef4fda8b13c0842048623e/
URN
urn:pw-repo:WUT53bea9c0b3ef4fda8b13c0842048623e

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