Publicação
Numerical modelling of the cyclic behaviour of timber-framed structures
| Resumo: | Ancient heritage is abundant with timber-framed structures that function as strengthening solutions with infill and as independent structural systems. In earthquake areas they have been used as seismic-resistant construction and their good behaviour during seismic events has been documented and observed. However, building typologies like Pombalino buildings in Lisbon have not experienced seismic activity and therefore their behaviour is unknown. Pombalino buildings and others are under risk of failure during seismic events if their mechanical behaviour is not properly quantified and understood. Traditional timber framed walls exhibit nonlinear hysteretic response under in-plane cyclic loading. To better understand their influence in the global response of buildings, it is important to define numerical modelling strategies for this type of constructive element. Therefore, the work presented in this thesis aims at better understanding the mechanical behaviour of timber frame walls based on numerical simulation. The experimental campaign by Poletti (2013) on in-place cyclic testing of traditional half-timbered frames and timber frames at the University of Minho is used as reference. Based on the experimental results, numerical models were developed that capture the cyclic response of traditional timber frame walls including flexural behaviour, pinching and strength degradation. The numerical models were constructed in the finite element software OpenSees with calibrated springs representing nailed connectors found in traditional half lap joints. 2-D nonlinear beam modelling was preferred over 3-D detailed finite element modelling to reduce computational effort. Three distinct timber frame models were developed in order to best capture the experimental response. A correlation was found between model output and experimental results and was used to develop a half-timbered frame model. These models are difficult to control nonlinear behaviour due to multiple hysteretic models that complicate analyses. A parametric study was conducted on both the half-timbered frame and timber frame by varying wall configuration and studying cumulative energy dissipation and the effect of slenderness and load capacity with increasing drift. A macro-model inspired by the macro-modelling of masonry infill walls is proposed at the end of the work as a simplified solution to avoid modelling complexity of traditional timber frames in masonry buildings while maintaining overall mechanical behaviour by concentrating all nonlinearity in the central connection. |
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| Autores principais: | Lukic, Relja |
| Ano: | 2016 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Ancient heritage is abundant with timber-framed structures that function as strengthening solutions with infill and as independent structural systems. In earthquake areas they have been used as seismic-resistant construction and their good behaviour during seismic events has been documented and observed. However, building typologies like Pombalino buildings in Lisbon have not experienced seismic activity and therefore their behaviour is unknown. Pombalino buildings and others are under risk of failure during seismic events if their mechanical behaviour is not properly quantified and understood. Traditional timber framed walls exhibit nonlinear hysteretic response under in-plane cyclic loading. To better understand their influence in the global response of buildings, it is important to define numerical modelling strategies for this type of constructive element. Therefore, the work presented in this thesis aims at better understanding the mechanical behaviour of timber frame walls based on numerical simulation. The experimental campaign by Poletti (2013) on in-place cyclic testing of traditional half-timbered frames and timber frames at the University of Minho is used as reference. Based on the experimental results, numerical models were developed that capture the cyclic response of traditional timber frame walls including flexural behaviour, pinching and strength degradation. The numerical models were constructed in the finite element software OpenSees with calibrated springs representing nailed connectors found in traditional half lap joints. 2-D nonlinear beam modelling was preferred over 3-D detailed finite element modelling to reduce computational effort. Three distinct timber frame models were developed in order to best capture the experimental response. A correlation was found between model output and experimental results and was used to develop a half-timbered frame model. These models are difficult to control nonlinear behaviour due to multiple hysteretic models that complicate analyses. A parametric study was conducted on both the half-timbered frame and timber frame by varying wall configuration and studying cumulative energy dissipation and the effect of slenderness and load capacity with increasing drift. A macro-model inspired by the macro-modelling of masonry infill walls is proposed at the end of the work as a simplified solution to avoid modelling complexity of traditional timber frames in masonry buildings while maintaining overall mechanical behaviour by concentrating all nonlinearity in the central connection. |
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