In the present paper, an analytical presentation of some popular aluminium systems that contribute to sustainability of structures is presented. Special emphasis has been given to the properties of aluminium, while the influence of these systems in the overall performance of the structure regarding environment and economy is described. In particular, characteristics of aluminium elements such as high reflectivity and recyclability and their role in life cycle analysis (LCA) are analyzed. The connections between energy efficiency and conservation of buildings and aluminium application are also discussed. Building applications such as curtain walls, window frames and facade sheets are presented and thoroughly investigated, considering their environmental and economic aspects. Furthermore, many innovative techniques that use aluminium elements in collaboration with other systems in order to produce renewable energy, such as solar panels and photovoltaics, are introduced. Finally, environmental innovations such as optimized ventilation mechanisms and light and shade management systems based on aluminium members are presented.

Floating modular energy islands (FMEIs) are modular, interconnected floating structures designed to collectively produce, store, convert, and transport renewable energy. This review aims to establish a foundation for developing innovative approaches to sustainably harness multi-energy sources in offshore environments. It leverages existing technological expertise while exploring new solutions to address specific challenges associated with FMEIs. The review initially presents existing technologies for floating energy structures and assesses their applicability to FMEI. The structural materials that could be utilised for the construction of a floating energy island are subsequently reviewed. Next, the offshore construction technologies suitable for FMEI are reviewed. Finally, studies on the life cycle assessment of hybrid energy systems are examined, highlighting the environmental advantages of integrating multiple renewable energy sources, thereby underscoring the potential of FMEIs.

Within the framework of optimisation of structural elements, in the last years, significant activity has been demonstrated towards developing new sectional designs beyond standardised forms aiming to combine aesthetic innovation, material efficiency, and weight over stiffness, together with structural reliability and manufacture cost savings. Moreover, in terms of sustainability performance, as material-weight reduction leads to less carbon emissions from production to installation processes, the pursuit of suitable materials that can correspond to this challenge becomes imperative. In this context, aluminium is lightweight and corrosion resistant, but due to its low elastic modulus, an increased cross-sectional stiffness is required. In this paper, 16 previously optimised aluminium cross-section profiles are presented and analysed using the finite element analysis software ABAQUS. The obtained ultimate compression resistances were compared with the predictions made in accordance with Eurocode 9, the direct strength method (DSM), and the continuous strength method (CSM). The percentage of difference of these design methods with respect to FE results is depicted. The outcomes point out the vagueness in accuracy of the prediction methods, particularly in reference to stocky or slender cross-sections.

The effectiveness of a hybrid technique for identifying seismic damage in planar, multistory, steel X- or V-braced frames is demonstrated here through an example of a six-story frame. This proposed technique, referred to as “M and P”, combines the instrumental monitoring (M) with pushover analysis (P). According to the methodology, the diagram of stepping eigenfrequencies of the frame in the inelastic region is initially plotted against seismic roof displacement. The fundamental natural frequency, detected through monitoring, is then utilized in this key diagram to reveal the inelastic roof displacement that corresponds to the damage state of the steel-braced frame. This displacement is subsequently used as the target in the pushover analysis, facilitating the identification of seismic damage within the existing steel-braced frame. Finally, the damage image is correlated with the damage stiffness matrix of the frame at the same inelastic roof displacement. The investigation results indicate that combining instrumental monitoring with pushover analysis using the eigenfrequencies curves established by the “M and P” technique allows for accurate identification of the seismic damage potential in existing damaged steel-braced frames. The “M and P” technique is a straightforward method for immediate damage assessment in steel structures after damage occurs, regardless of the cause.