PSI - Issue 64

Gabriella Maselli et al. / Procedia Structural Integrity 64 (2024) 1743–1751 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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shapes of any length. It is a low-cost process because it directly converts continuous fibres and resin into a finished part. The fibres are continuously impregnated and pulled through a heated mould, where they are shaped and hardened. From a constitutive point of view, pultruded elements can be considered as linear elastic, homogeneous and transversely isotropic in the case of aligned fibres, with the plane of isotropy normal to the longitudinal axis, i.e. the pultrusion axis. From the design point of view, particular attention must be paid to: (i) their mechanical behaviour; (ii) the connection technology between the elements. Regarding (i), their overall mechanical behaviour is heavily affected by warping strains as well as shear deformations due to their relatively low elastic moduli, which often makes design for serviceability and stability the governing limit states (Ascione et al. 2015). Furthermore, regarding the connections of FRP structures (ii), they are considered essential to provide the required load bearing capacities, but present challenges due to the brittle and anisotropic nature of the material. Currently, connections are mainly made with bolts, but must be carefully designed as holes in the composite material can create brittle zones that affect strength. The possible inclination of the load relative to the direction of the fibres can further compromise the strength of the connections (Ascione et al. 2017). 3. Techniques for the economic-environmental evaluation of circular strategies Products and strategies of CE have to be evaluated from an (i) economic perspective, using Life Cycle Costing (LCC) approaches that allow, among other objectives, to evaluate alternative design options at different scales (building/system/component/material); (ii) environmental perspective, mainly by implementing methods such as Life Cycle Assessment (LCA); (iii) social , using the Social-Life Cycle Assessment (S-LCA) to assess the socio-economic aspects of services, projects, and products. LCC has been used since the 1970s to assess the total life-cycle costs of products and to provide information in strategic business and political decision-making (UNEP/SETAC 2009). However, there are references to the use of the methodology by the US Department of Defence in the 1960s to assess the costs of military equipment (Jolliet et al. 2015). As normed in the Standard ISO 15686-5:2008, repealed with Standard ISO 15686 – 5:2017, the LCC considers all costs: (i) initial, such as investment costs and installation costs; (ii) future, such as energy costs, operating costs, maintenance costs, capital replacement costs, financing costs, as well as all resale, recovery or disposal costs that occur over the considered «cradle-to-grave» life span. According to a widely accepted classification, three types of LCC can be distinguished: (a) financial (fLCC) or conventional, which considers the internal costs linked to a specific product and borne by a specific actor and which results in the estimation of the Global Cost; (b) environmental (eLCC), which also takes into account monetised environmental externalities; (c) social (sLCC), which can further expand the boundaries of the analysis by including direct and indirect costs borne by society (Jansen et al., 2020). Life Cycle Assessment (LCA) is a standardised method that aims to assess the environmental impacts of products and services throughout their life cycle, from the extraction of raw materials to their disposal. This process consists of four steps according to ISO 14040 and ISO 14044: (a) definition of the objectives and scope, which includes the identification of the functional unit and system boundaries under analysis; (b) inventory, which consists of the collection and quantification of data related to input and output flows along all phases of the product life cycle; (c) assessment of impacts, where the collected information is analysed and aggregated into different environmental impact categories; (d) interpretation of the results and formulation of recommendations to mitigate environmental impacts. LCA is widely used to assess the environmental performance of services, products and industrial systems, as well as construction and building projects. However, some studies have identified some challenges in the application of LCA, including difficulties in data comparability, lack of sufficient and qualified data, data scalability problems, and uncertainties in the reporting of results. S-LCA is a methodology that can assess the social and socio-economic aspects of services, projects and products, considering positive and negative, actual and potential impacts along the life cycle. The indicators of S-LCA can be diverse: sustainable behaviour, health, safety, casualties, human rights, accountability, architectural quality, architectural diversity, added social value, future value, historical continuity, cultural heritage, governance, socio-economic impacts and labour policies (Kloepffer, 2008; Liu and Qian, 2018; Costa et al., 2019).