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This paper reports on the development of a general-purpose Eurocode-compliant component-based connection finite element for steel-to-steel joints in fire. The development begins by utilising the temperature-dependent connection component characteristics previously developed at the University of Sheffield to create a component-based connection finite element to model flush endplate connections. Subsequently the element was extended to a new connection type with high ductility, the reverse channel. The component models have been developed for the reverse channel under tension and compression. The element has been incorporated into the nonlinear global structural analysis program Vulcan, in which it has been used along with a static-dynamic formulation. The use of the element is illustrated by modelling a fire test at the University of Manchester in which reverse channel connections were used.

The paper is focused to the temperature distribution in the reverse channel connections to concrete filled tubular column during two fire tests on an experimental building in Veselí nad Lužnicí. Temperatures of connections without fire protection as well as fire protected connections were investigated. The connected beams were without fire protection which allows to take into account a membrane action of a composite ceiling without fire resistance reduction of the connections.

The design methods currently proposed by the codes prescribe the strength assessment of structures to be based on their strength limit state. These design methods can be applied to isolated steel members to determine their design strengthin fire. The real response of a structural member is, however, more complex due to the thermal expansion and the presence of restraints against this expansion by the surrounding structure. It is therefore imperative to study the response of a structural member at high temperature in a way which includes its interaction with its surroundings. This paper focus on the numerical investigation of steel beams in structural frames connected to concrete filled tubular (CFT) columns through reverse channel connections and comparison to hand calculation procedures. Finite element models (FEM) of the sub-frames were validated against fire tests conducted on sub-frames and then their results were compared to the proposed simplified hand calculation procedures (HCM).

In this paper, a closed-form analytical solution for the prediction of moment-rotation and the rotational stiffness-rotation curves of I-shaped beam to cylindrical column connections, commonly used on offshore platforms, at room and elevated temperatures, are presented.

An analytical solution for the prediction of moment-rotation and the rotational stiffness-rotation curves of I-shaped beam to cylindrical column connections is presented. The results of this model are compared with those of a non-linear coupled mechanical-thermal finite element model and small-scale experimental tests previously provided by the authors.

In this paper, a closed-form analytical solution for the prediction of moment-rotation and the rotational stiffness-rotation curves of I-shaped beam to cylindrical column connections, commonly used on offshore platforms, at room and elevated temperatures, is presented. The required yield and plastic moments in this model are provided as an extension to Roark's relationships. The results of this model are compared with those of a non-linear coupled mechanical-thermal finite element model and small-scale experimental tests previously provided by the authors. A reasonable agreement has been found between the analytical model results and the experimental/numerical modeling results.

This article is extracted from the author’s doctoral thesis, and all its achievements belong to the authors of the article.

In order to improve the robustness of bare-steel and composite structures in fire, a novel axially and rotationally ductile connection has been proposed in this paper.

The component-based models of the bare-steel ductile connection and composite ductile connection have been proposed and incorporated into the software Vulcan to facilitate global frame analysis for performance-based structural fire engineering design. These component-based models are validated against detailed Abaqus FE models and experiments. A series of 2-D bare-steel frame models and 3-D composite frame models with ductile connections, idealised rigid and pinned connections, have been created using Vulcan to compare the fire performance of ductile connection with other connection types in bare-steel and composite structures.

The comparison results show that the proposed ductile connection can provide excellent ductility to accommodate the axial deformation of connected beam under fire conditions, thus reducing the axial forces generated in the connection and potentially preventing the premature brittle failure of the connection.

Compared with conventional connection types, the proposed ductile connection exhibits considerable deformability, and can potentially enhance the robustness of structures in fire.

In this paper, the authors adopt the theory of the circular economy to study the transitions that take place in three case studies in Mexico and Ecuador. The work is aimed to systematize a circular economy assessment tool that fosters opportunities for improvement in business practices.

The methodology is based on a descriptive quantitative analysis, where a checklist is made with 91 items and nine study variables. This is from the study of the bibliography and business practice. Furthermore, the neural network method is used in a case study to predict the level of circular economy and the importance of each variable according to the sensitivity by the Lek’s profile method.

It is based on a descriptive quantitative analysis, where a checklist with 91 items and nine study variables is made, defined from a bibliographic study and business practice. Furthermore, the neural network method is used in a case study to predict the level of circular economy and the importance of each variable based on sensitivity.

The application of the tool requires prior knowledge of the circular economy approach, which is why specialized personnel are needed for its application. This makes research more expensive in time and human resources.

The practical and methodological contribution of this work lies in the feasibility of the tool that favors the definition of improvement actions for the implementation contribution to the circular economy in business practices.

The social contribution is framed in the gradual transition to circular economy approaches in underdeveloped countries.

The use of the neural network method to predict the level of circular economy in a case study allows making decisions in a predictive way. This encourages the development of the circular economy according to the context needs.

En este trabajo adoptamos la teoría de la economía circular para estudiar las transiciones que ocurren en tres casos de estudio en México y Ecuador. El trabajo tiene como objetivo sistematizar una herramienta de evaluación de la economía circular que fomente oportunidades de mejora en las prácticas empresariales.

La metodología se basa en un análisis cuantitativo descriptivo, donde se elabora un checklist con 91 ítems y nueve variables de estudio. Esto a partir del estudio de la bibliografía y la práctica empresarial. Además, el método de la red neuronal se utiliza en un estudio de caso para predecir el nivel de economía circular y la importancia de cada variable según la sensibilidad utilizando el método Lekprofile.

Los resultados muestran que la herramienta es aplicable a diferentes contextos y simultáneamente permite la evaluación de la economía circular de forma holística. Además, la herramienta se puede vincular a técnicas predictivas, como el método de red neuronal. Esto se demostró en un estudio de caso.

en el uso del método de redes neuronales para predecir el nivel de economía circular en un caso de estudio. Esto permite la capacidad de tomar decisiones de forma predictiva y esto incentiva el desarrollo de la economía circular según la necesidad del contexto.

Las limitaciones se centran en la necesidad de conocer el tema de la economía circular para la aplicación de la herramienta. Por lo tanto, se necesita capacitación antes de comenzar un nuevo estudio. Esto encarece la investigación en tiempo y recursos humanos.

El aporte práctico y metodológico de este trabajo radica en la viabilidad de la herramienta que favorece la definición de acciones de mejora para la contribución de la implementación a la economía circular en las prácticas empresariales.

La contribución social es parte de la transición gradual a enfoques de economía circular en países subdesarrollados.

This research studies a plastic recycling system from a reverse logistics angle and investigates the potential benefits of a multimodality strategy to the network design of plastic recycling. This research aims to quantify the impact of multimodality on the network, to provide decision support for the design of more sustainable plastic recycling networks in the future.

A MILP model is developed to assess different plastic waste collection, treatment and transportation scenarios. Comprehensive costs of the network are considered, including emission costs. A baseline scenario represents the optimized current situation while other scenarios allow multimodality options (barge and train) to be applied.

Results show that transportation cost contributes to about 7 percent of the total cost and multimodality can bring a reduction of almost 20 percent in transportation costs (CO₂‐eq emissions included). In our illustrative case with two plastic separation methods, the post‐separation channel benefits more from a multimodality strategy than the source‐separation channel. This relates to the locations and availability of intermediate facilities and the quantity of waste transported on each route.

This study applies a reverse logistics network model to design a plastic recycling network with special structures and incorporates a multimodality strategy to improve sustainability. Emission costs (carbon emission equivalents times carbon tax) are added to the total cost of the network to be optimized.

The purpose of this paper is to identify the major reverse logistics design aspects in used clothing value chains, and those enabling and challenging manifestation of value creation.

This research is based on an exploratory study of 12 established organizations in Swedish used clothing networks. Data were gathered through semi-structured interviews, secondary sources, and subsequent field visits.

Empirical insights on how various design aspects influence value creation in used clothing value chains are provided. Crucial among these are strategic and consistent collection, presence of multi-channel sales, and communication of post-retail concepts for manifesting value by bolstering consumer satisfaction, environmental motivation, and corporate image. Inter-organizational collaboration in reverse logistics processes and workplace training, further renders higher economic, environmental and information values.

The paper proposes a holistic framework of design aspects in reverse value chains, and extends existing knowledge on how these aspects manifest value creation. By doing so, a nuanced view of the design aspects is offered by highlighting how they can differentially, either enable, or challenge value creation. In this connection, seven supporting propositions are developed for in-depth future research.

The paper includes implications for the devising strategic solutions for higher value creation, by understanding of the key enablers and challenges, for many actors in the used clothing networks.

The role of various design aspects in reverse value chains for manifesting multifaceted stakeholder value creation is explicitly defined in the paper.

This study provides a comprehensive framework of adaptation in triadic business relationship settings in the service sector. The framework is based on the industrial network approach (see, e.g., Axelsson & Easton, 1992; Håkansson & Snehota, 1995a). The study describes how adaptations initiate, how they progress, and what the outcomes of these adaptations are. Furthermore, the framework takes into account how adaptations spread in triadic relationship settings. The empirical context is corporate travel management, which is a chain of activities where an industrial enterprise, and its preferred travel agency and service supplier partners combine their resources. The scientific philosophy, on which the knowledge creation is based, is realist ontology. Epistemologically, the study relies on constructionist processes and interpretation. Case studies with in-depth interviews are the main source of data.

This paper aims to analyze the benefits of the blockchain to the circular economy (CE), which is composed of both closed-loop supply chain (CLSC) systems and reverse omnichannel solutions. By ensuring transparency, traceability, visibility and security, the blockchain allows firms to acquire operational capabilities through a CLSC and service capabilities through a reverse omnichannel, which can boost business performance considerably. The related network of relationships can be reinforced by establishing incentives, which entail both smart contracts in the blockchain and active return approaches in CE.

After identifying the boundaries of the theoretical framework, several research hypotheses are developed according to the literature review and emerging gaps. These gaps link to the impact of the blockchain on CE systems (CLSC and reverse omnichannel), as well as the influence on business performance. The hypotheses are then tested using structural equation modeling and adopting a partial least squares-path modeling technique on a dataset composed of 157 firms. Finally, multigroup analysis is used to test the impact of incentives on the research hypotheses.

The blockchain facilitates a more efficient CE system, although reverse omnichannel solutions seldom bring any benefits to performance. The shift from a passive to an active return approach must be carefully evaluated. The CLSC network can benefit from an active return approach by developing appealing incentives for collectors and enhancing the positive effects of the blockchain. In contrast, consumer incentives can have detrimental effects on the blockchain. Various combinations of incentives can only bring a few business performance increases, while collector incentives are vital to reinforce the CE system's operational and service capabilities.

This paper takes a new approach toward the study of CE, which considers a dual circular system composed of a CLSC and a reverse omnichannel. The research explores whether the adoption of blockchain technology enables better return processes by improving the operations in CLSC and services in reverse omnichannel. Finally, this is the first empirical work to evaluate the benefits emerging from incentives, which can activate smart contracts in the blockchain and enable active return approaches in CE.