This paper provides a discussion and thoughtful application on a large sample of the procedures for the classification of existing bridges recently adopted in Italy and defined within the Italian Guidelines for the classification, risk management, safety evaluation and monitoring of existing bridges and the early published Operating Instructions. Focusing on the classification at the territorial level, first the logic flows to the classification on the base of the structural risk are shown, resulting in the definition of the “structural warning class”, providing the motivations that support the criteria for the definition of such procedures. Then, a statistical analysis of the results obtained from the classification of 661 existing Italian bridges is performed, focusing on the vulnerability classification and on the influence of each parameter on its evaluation.

Automated Rack Supported Warehouses (ARSWs), consisting in huge steel buildings offering optimized storage solutions, have been facing a huge diffusion in the last decade, mainly due to the necessity of having bigger and more efficient places to stock and handle goods through automated systems. However, there is not a specific regulatory framework for them, and they are currently being designed adopting the approach used for traditional steel racks. Even if traditional steel racks and ARSWs have several common aspects, there are relevant differences that do not allow to adopt the same design approach, especially for seismic actions. With the aim of highlighting the factors and parameters currently influencing the seismic design and the behaviour of these constructions, and the consequent need of a different design approach, the present paper presents a critical analysis of the seismic design approach currently adopted by technicians and designers. Then, a set of 5 structures designed by 5 of the major European companies specialized in this field is used to perform both the critical analysis of the different design approaches adopted and the assessment of the seismic performance. The results of the seismic assessment highlight the main typical criticalities and the necessity of a novel proper design approach.

Steel racking systems are widely adopted for storage purposes: they are thin-walled structures composed of consecutive trusses, connected with beams on which the palletized goods are stored. Their geometry and structural configuration strongly depend on market and operator necessities, and, in modern applications, racks can also function as the supporting structure of the warehouse itself in the form of Rack Supported or High-Bay Warehouses. With the increase of the overall geometric dimensions and the global weight of the stored material, the seismic action becomes more relevant for the design. Along these lines, the development and experimental testing of a dedicated seismic design approach for ductile steel racks is here presented, with particular attention to Rack Supported Warehouses. This approach exploits the ductility of trusses introduced via the plastic ovalization mechanism of the diagonal-to-upright connections while a tailored capacity design is used to assure the elastic behaviour of the rest of the structure and to keep the brittle failure mechanisms at bay.

Steel racking systems are widely adopted for storage purposes: they are thin-walled structures composed of consecutive trusses, connected with beams on which the palletized goods are stored. Their geometry and structural configuration strongly depend on market and operator necessities, and, in modern applications, the racks can also function as the supporting structure of the warehouse itself in the form of Rack Supported or High-Bay Warehouses. With the increase of the overall geometric dimensions and the global weight of the stored material, the seismic action becomes more relevant for the design. Along these lines, we present the development and experimental testing of a dedicated seismic design approach for ductile steel racks, with particular attention to Rack Supported Warehouses. This approach exploits the ductility of trusses introduced via the plastic ovalization mechanism of the diagonal-to-upright connections while a tailored capacity design is used to assure the elastic behaviour of the rest of the structure and to keep the brittle failure mechanisms at bay.

Snap-clip systems are widely employed in product engineering, yet their application in the constructions field remains limited. This study investigates the mechanical behavior of a cantilever-type snap-clip connection specifically conceived for structural applications and manufactured through metal Additive Manufacturing, focusing on the assembly and retention response of the connection. An analytical formulation is developed to predict insertion forces during the assembly process. The model describes the interaction between clip deformation, contact mechanics, and frictional effects, and enables the derivation of optimized head geometries that minimize peak assembly force. Simplified two-dimensional finite element simulations are first used to validate the analytical approach, followed by the analyses of the design constraints imposed by Laser Powder Bed Fusion for the production of three-dimensional assembly specimens. Experimental tests at both material and snap clip connection levels are then used, the former to assess the effective friction coefficient of the printed material and the latter to evaluate the assembly forces, the repeatability of the assembly phase and the ultimate load bearing capacity. Results demonstrate that the snap-clip response can be accurately predicted through the proposed analytical framework and significantly tuned through geometric optimization. The study establishes a mechanical foundation for structurally scalable, reversible, and tool-less snap-clip connections enabled by additive manufacturing.