Publicação
Experimental and numerical assessment of the seismic behaviour of log and cross- Laminated Timber Systems
| Resumo: | This thesis focuses on the study of the seismic behaviour of two engineered timber construction systems, the first of which, is the log house system - one of the earliest forms of timber construction that is in use even till date, albeit with significant improvements. The second construction system is one of the most recent entrants into the building industry, the cross-laminated timber (CLT) system. The thesis aims at assessing the seismic resistance of the aforementioned systems based on a combined approach of experimental tests and numerical simulations. The focus is more on the CLT system as log houses offer limited scope for flexibility in design and geometry and also pose restrictions with regard to the number of storeys that can be constructed. Full-scale specimens of a log house and CLT house were subjected to a series of seismic tests with peak ground accelerations ranging from 0.07g to 0.5g at the National Laboratory for Civil Engineering (LNEC) in Lisbon, Portugal, as part of the SERIES project on multi-storey timber buildings. Neither of the structures underwent any major damage and remained intact at the end of the tests. Prior to the shaking table tests, quasi-static tests were conducted on the connectors and walls used in the structures. Based on the results of the component and global level testing, threedimensional finite element models of the two structures were developed. In the case of the log house, it was difficult to characterize the behaviour of each of the components that contribute to lateral load resistance and hence only a simple representative model of the structure, whose validity was determined based on linear modal analysis, was developed in SAP2000. For the CLT house, models that could simulate the behaviour of the angle brackets and hold-downs were developed in OpenSees and SAP2000 and their validity was determined by a comparison with the experimental results at both connector and wall levels. The parameters affecting the lateral load resistance of CLT walls such as vertical load, wall length and the presence of openings, were investigated via a sensitivity analysis. An analytical prediction of the lateral load capacity of CLT walls connected to a rigid foundation using connectors with known mechanical properties was made using MATLAB. A 3D finite element model of the CLT building was developed in SAP2000 because its popularity among practising engineers and its user-friendly interface. The validity of the full-scale model was determined by subjecting it to linear and nonlinear analyses. The pushover analyses revealed that the CLT house was quite far from collapse. Finally, some of the factors that can lower the capacity of CLT structures were investigated. |
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| Autores principais: | Aranha, Chrysl Assumpta |
| Assunto: | Seismic behaviour Finite element modelling Timber structures Comportamento sísmico Modelação por elementos finitos Estruturas de madeira |
| Ano: | 2016 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | This thesis focuses on the study of the seismic behaviour of two engineered timber construction systems, the first of which, is the log house system - one of the earliest forms of timber construction that is in use even till date, albeit with significant improvements. The second construction system is one of the most recent entrants into the building industry, the cross-laminated timber (CLT) system. The thesis aims at assessing the seismic resistance of the aforementioned systems based on a combined approach of experimental tests and numerical simulations. The focus is more on the CLT system as log houses offer limited scope for flexibility in design and geometry and also pose restrictions with regard to the number of storeys that can be constructed. Full-scale specimens of a log house and CLT house were subjected to a series of seismic tests with peak ground accelerations ranging from 0.07g to 0.5g at the National Laboratory for Civil Engineering (LNEC) in Lisbon, Portugal, as part of the SERIES project on multi-storey timber buildings. Neither of the structures underwent any major damage and remained intact at the end of the tests. Prior to the shaking table tests, quasi-static tests were conducted on the connectors and walls used in the structures. Based on the results of the component and global level testing, threedimensional finite element models of the two structures were developed. In the case of the log house, it was difficult to characterize the behaviour of each of the components that contribute to lateral load resistance and hence only a simple representative model of the structure, whose validity was determined based on linear modal analysis, was developed in SAP2000. For the CLT house, models that could simulate the behaviour of the angle brackets and hold-downs were developed in OpenSees and SAP2000 and their validity was determined by a comparison with the experimental results at both connector and wall levels. The parameters affecting the lateral load resistance of CLT walls such as vertical load, wall length and the presence of openings, were investigated via a sensitivity analysis. An analytical prediction of the lateral load capacity of CLT walls connected to a rigid foundation using connectors with known mechanical properties was made using MATLAB. A 3D finite element model of the CLT building was developed in SAP2000 because its popularity among practising engineers and its user-friendly interface. The validity of the full-scale model was determined by subjecting it to linear and nonlinear analyses. The pushover analyses revealed that the CLT house was quite far from collapse. Finally, some of the factors that can lower the capacity of CLT structures were investigated. |
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