Browsing by Author "Paiva, Lucas"
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- 3D numerical modeling of geosynthetics for soil reinforcement: a bibliometric analysis and literature reviewPublication . Paiva, Lucas; Pinho-Lopes, Margarida; Paula, António Miguel; Valente, RoberttSoil reinforcement using geosynthetics is an efficient and cost-effective solution for a variety of geotechnical structures. Along with the increasing use of geosynthetics, there is a need to expand and enhance the design methodologies for these elements, which are still frequently based on conservative limit equilibrium approaches. In this paper, a bibliometric analysis was conducted on geosynthetic-reinforced soil structures (GRS), identifying the state of the art, research trends, and other indicators. The data were obtained from the Scopus platform and processed by VOSViewer v1.6 software. The initial search comprised 552 papers and the screening process selected 516 relevant papers from 1992 to October 2023. The study analyzed the occurrence of publications by year, keyword trends, authors, citations/co-citations, and bibliographic coupling. Then, a focus was given to 3D modeling research on geosynthetics, highlighting the dominant modeling techniques, material properties, and design challenges in GRS. The bibliometric analysis provided a crucial guideline in the identification of relevant papers and research trends, and a series of conclusions were presented regarding the 3D modeling techniques, choice of material properties, and boundary conditions.
- Análise numérica de uma ligação de treliça com chapas metálicas dentadas: caso de estudo de uma ligação tipo heel jointPublication . Paiva, Lucas; Braz-César, Manuel; Paula, António MiguelTreliças em madeira com ligações tradicionais por pinos são geralmente modeladas como pórticos de ligações rígidas, e os esforços nas barras são depois transmitidos para o dimensionamento das ligações. Outras metodologias recomendam que a análise seja feita com mais rigor, levando em conta a distribuição de tensões, comportamento da madeira e a avalição da distribuição de esforços na ligação. Há uma grande gama de informação relacionada às ligações do tipo pinos, mas a análise mecânica dos esforços em ligações com chapas metálicas dentadas ainda está em desenvolvimento. O presente documento compara duas metodologias para a distribuição de esforços nas linhas de ruptura de ligações com chapas metálicas dentadas, utilizando uma abordagem analítica e um método numérico, utilizando software comercial Midas/Gen. Os resultados apresentam a validação do modelo analítico para o caso mais simples de uma linha de ruptura, mas confrontam as premissas da redistribuição dos esforços entre linhas adjacentes.
- Computational modeling of joint lines in punched metal plate fastenersPublication . Paiva, Lucas; Braz-César, Manuel; Paula, António MiguelPunched metal plate fasteners (nail plates) are currently the top choice in the wooden-truss industry because of its high mechanical capacity and easy automated assembly. Here, a computational modelling is proposed to evaluate the force distribution within the plate’s anchorage area and in the rupture lines, a structural system that in most cases is highly hyperestatic and does not feature an analytical solution. This method can be applied to areas with multiple gaps (rupture lines) and therefore its analysis is discussed from a quantitative and qualitive point of view.
- Geosynthetics for sustainable cities: 3D models and mechanical damagePublication . Paiva, Lucas; Lopes, Margarida Pinho; Valente, R.; Paula, António MiguelGeosynthetics for sustainable cities: 3D models and mechanical damage.
- Geosynthetics for sustainable cities: 3D numerical models and mechanical damagePublication . Paiva, Lucas; Paula, António Miguel; Lopes, Margarida Pinho; Valente, R.Geotechnical works play a major role on the infrastructure development. Geosynthetics are the most efficient, cost-effective and environmentally- friendly solution to a variety of geotechnical structures (e.g., roadways, foundations, retaining walls). Thus, improving the design methods of geosynthetics can increase safety and reduce infrastructure costs (GDS goal 9).Verify if constitutive models and parameters replicate the response of real structures. Improve the existing models with nonlinear & time- dependent constitutive models
- Geosynthetics for sustainable cities: 3D numerical models and mechanical damagePublication . Paiva, Lucas; Paula, António Miguel; Lopes, Margarida Pinho; Valente, R.Geotechnical works play a major role on the infrastructure development. Geosynthetics are the most efficient, cost-effective and environmentally- friendly solution to a variety of geotechnical structures (e.g., roadways, foundations, retaining walls). Thus, improving the design methods of geosynthetics can increase safety and reduce infrastructure costs (GDS goal 9).
- Load transfer models in joint lines of punched metal plate fastenersPublication . Paiva, Lucas; Braz-César, M.T.; Souza, Edson Florentino deTimber joints are a key part of timber structures, and their performance is a major requisite to successful timber constructions. Among all the connection types, punched metal plate fasteners are the most economical and e cient, reasons why this connection dominates the prefabricated truss industry. However, the structural load bearing capacity of these timber connections is mechanically complex and di cult to analyse. Besides, the current standards oversimplify many current joint con gurations and don’t provide a guideline to predict the stress distribution within the plate. Most research to date has focused on modelling and testing punched metal plate fasteners from a FEM 3-D perspective, accounting for all its parts (timber, plate, teeth and toothwood interface) whilst knowledge on the 2-D stress distribution within the plate is limited. The complete joint modeling with a 3-D model based on FEM gives precise results on the mechanical behavior of those plates, but requires more time to model and more computational processing. In a truss design point of view, where many connections need to be verify, a 2-D static model is usually the annalist’s choice, and despite the large industrial application of metal plates, the internal force ow still lacks research. The research reported in this thesis describes four methods to account for the stress distribution in punched metal plate fasteners. Each model is based on a particular plate behavior and aims to identify the critic rupture lines to successfully attend the ultimate limit state criteria. A heel joint was taken as starting point to study the stress distribution in the rupture lines, and a computational tool (NPCalc) was developed based on the current standards to verify the main connection aspects. The connection was modeled by the four methods and the results were analysed and compared, seeking to identify how the stress ows within the plate once the loads are applied. Two manual and two numerical methods were presented. The results showed a considerable variability with the model’s choice, and the numerical models pointed to be more conservative. However, the simple regions (delimited by only one rupture line) presented equal results regardless the chosen model. Finally, the conclusions of the elaborated research are presented, discussing the extension of its results and the suggestions for future development, in order to complement the analysis and modeling of wooden trusses with punched metal plate fasteners.
- Numerical analysis of load distribution in joint lines with punched metal plate fastenersPublication . Paiva, Lucas; Braz-César, Manuel; Paula, António MiguelWood trusses with traditional bolted or nailed connections are generally modeled as pinned joints, and the forces on the wooden members are directly transmitted to the connections by shear plane contact. Other methodologies recommend that the analysis should be done more rigorously, taking into account the wood behavior and the evaluation of stress distribution within the connection area. There is a wide range of related data to pin-type connections, but the mechanical analysis of punched metal plate fasteners (nail plates) is still under developed. Nail plate connections are capable of transfer moments, therefore, appropriated modeling should be applied. The present paper compares two methodologies for the stress distribution in the rupture lines of nail plates, using an analytical approach and a numerical method with the commercial software Midas/Gen. The results show a quantitative parity for the proposed analytical model in the case of a single joint line, but the stresses diverge in both methods for zones that presents more than one joint line.
- Numerical analysis of load distribution in joint lines with punched metal plate fastenersPublication . Paiva, Lucas; Braz-César, Manuel; Paula, António MiguelWood trusses with traditional bolted or nailed connections are generally modeled as pinned joints, and the forces on the wood members are directly transmitted to the connections by shear plane contact. Other methodologies recommend that the analysis should be done more rigorously, taking into account the wood behavior and the evaluation of stress distribution within the connection area. There’s a wide range of related data to pin-type connections, but the mechanical analysis of punched metal plate fasteners (nail plates) is still under development. Nail plate connections are capable of transfer moments, therefore, appropriated modeling should be applied. The present paper compares two methodologies for the stress distribution in the rupture lines of nail plates, using an analytical approach and a numerical method with the commercial software Midas/Gen. The results shows a quantitative parity for the proposed analytical model in the case of a single joint line, but the stresses diverge in both methods for zones that presents more than one joint line.
- Numerical analysis of load distribution in joint lines with punched metal plate fastenersPublication . Paiva, Lucas; Braz-César, Manuel; Paula, António MiguelWood trusses with traditional bolted or nailed connections are generally modeled as pinned joints, and the forces on the wood members are directly transmitted to the connections by shear plane contact. Other methodologies recommend that the analysis should be done more rigorously, taking into account the wood behavior and the evaluation of stress distribution within the connection area. There’s a wide range of related data to pin-type connections, but the mechanical analysis of punched metal plate fasteners (nail plates) is still under development. Nail plate connections are capable of transfer moments, therefore, appropriated modeling should be applied. The present paper compares two methodologies for the stress distribution in the rupture lines of nail plates, using an analytical approach and a numerical method with the commercial software Midas/Gen. The results shows a quantitative parity for the proposed analytical model in the case of a single joint line, but the stresses diverge in both methods for zones that presents more than one joint line.