Publicação
Robustness of multi-story timber buildings in seismic regions
| Resumo: | In the past few years, the construction of multi-storey timber buildings has increased signi - cantly in locations where high intensity ground motions are likely to occur. On the other hand, the fast development of wood engineered products, as glued-laminated timber (GLT) and crosslaminated timber (CLT), has been challenging researchers to provide adequate guidelines for design and assessment of structures built in seismic regions. Some guidelines and analysis methods considered in seismic design can improve robustness, which is commonly described as the ability of structures to sustain limited damage without disproportionate e ects. This thesis main objective is the development of numerical modeling approaches for seismic and robustness assessment of multi-storey timber buildings. The work is divided in three distinct parts that complement each other. First, given the importance of diaphragms to transfer inertial loads to the lateral resisting systems, a phenomenological computational model approach for CLT diaphragms was proposed and validated by comparing numerical results to experimental data obtained from a two-story full-scale building tested on a shake-table. A second part of the thesis focused on the seismic performance of a three-story building through a probabilistic approach, which accounts for uncertainties in mechanical properties of members and connections. Nonlinear static analyses and multi-record incremental dynamic analyses were performed to characterize the q-factor and develop fragility curves for di erent damage levels. The results indicate that the detailing requirements of Eurocode 5 and Eurocode 8 are su cient to achieve the required performance, even though they also indicate that these requirements can be optimized to achieve more cost-e ective connections and members. Finally, the progressive collapse potential of seismic resistant heavy-timber structures was studied through an alternate load path analysis (ALPA). This robustness assessment involved nonlinear static analyses (pushdown analyses) that include uncertainties related to material properties and applied loads. Fragility functions were developed for di erent column loss scenarios and for two distinct diaphragm solutions. The rst one makes use of cross-laminated timber (CLT) panels connected with half-lap joints, while the second solution consists of a low weight solution with 18 mm oriented strand boards fastened to the GLT joists. The results indicate that the structural capacity for developing alternative load paths is highly dependent on the rotational capacity of connections. |
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| Autores principais: | Rodrigues, Leonardo Filipe Guilherme |
| Assunto: | Engenharia e Tecnologia::Engenharia Civil |
| Ano: | 2019 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | In the past few years, the construction of multi-storey timber buildings has increased signi - cantly in locations where high intensity ground motions are likely to occur. On the other hand, the fast development of wood engineered products, as glued-laminated timber (GLT) and crosslaminated timber (CLT), has been challenging researchers to provide adequate guidelines for design and assessment of structures built in seismic regions. Some guidelines and analysis methods considered in seismic design can improve robustness, which is commonly described as the ability of structures to sustain limited damage without disproportionate e ects. This thesis main objective is the development of numerical modeling approaches for seismic and robustness assessment of multi-storey timber buildings. The work is divided in three distinct parts that complement each other. First, given the importance of diaphragms to transfer inertial loads to the lateral resisting systems, a phenomenological computational model approach for CLT diaphragms was proposed and validated by comparing numerical results to experimental data obtained from a two-story full-scale building tested on a shake-table. A second part of the thesis focused on the seismic performance of a three-story building through a probabilistic approach, which accounts for uncertainties in mechanical properties of members and connections. Nonlinear static analyses and multi-record incremental dynamic analyses were performed to characterize the q-factor and develop fragility curves for di erent damage levels. The results indicate that the detailing requirements of Eurocode 5 and Eurocode 8 are su cient to achieve the required performance, even though they also indicate that these requirements can be optimized to achieve more cost-e ective connections and members. Finally, the progressive collapse potential of seismic resistant heavy-timber structures was studied through an alternate load path analysis (ALPA). This robustness assessment involved nonlinear static analyses (pushdown analyses) that include uncertainties related to material properties and applied loads. Fragility functions were developed for di erent column loss scenarios and for two distinct diaphragm solutions. The rst one makes use of cross-laminated timber (CLT) panels connected with half-lap joints, while the second solution consists of a low weight solution with 18 mm oriented strand boards fastened to the GLT joists. The results indicate that the structural capacity for developing alternative load paths is highly dependent on the rotational capacity of connections. |
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