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Due to their lightness and simple connectivity, steel racking systems are typically considered as “low-dissipative” structures, which is reflected in the modern seismic codes by the absence of capacity design and the adoption of low behaviour factors. This limited capability of stress redistribution significantly increases the vulnerability of racks under beyond-design seismic hazards and raises the demand for more resilient designs. Along these lines, the proposed Plastic Ovalization Strategy (POS) attempts to increase the ductility of the individual upright frames comprising the cross-aisle direction of racks, and at the same time to preserve their low-cost and easy-to-assemble nature. This is achieved by tasking the bearing failure mechanism of the diagonal bolt hole to absorb seismic deformations, while capacity design is employed to keep the rest of the structure in the elastic zone. Following a detailed discussion on the motives and basic principles of the strategy, two high-rise racking systems are designed twice by professional engineers, once using standard approaches and then by additionally employing the proposed POS rules. Finally, the two design solutions are compared by conducting a comprehensive seismic assessment, which employs a phenomenological macro-model comprising elastic elements and nonlinear springs to simulate the bearing failure mechanism.

Transparency and structural lightness are inspiring ideas in the design of footbridges. Glass is the most performing transparent material to be used for structural purposes because of its h...

Ground penetrating radar is a non-invasive technique that, amongst the various available state-of-the-art methods, is capable of accurately locating both metallic and nonmetallic buried objects. The main object of this paper is to describe the application of a GPR strategy to the non-destructive testing of concrete structures, particularly bridges, where there is a need to identify, quantify and categorize structural reinforcements. The new C-Thrue radar, developed by IDS GeoRadar, was used to investigate two bridges near Pisa (Italy). The acquisition of dense and regular grids was used to provide a full reconstruction of the geometry of the investigated area. Moreover, through the use of sensors in different polarizations, and dedicated data processing techniques, the C-Thrue radar enables the creation of spatially correlated data sets that represent scanned 3-D volumes of the ground, allowing demonstrable benefits in overall assessment of the required structural parameters.

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.

Background: The lack of codified standards for the design of automated rack supported warehouses forced engineers to use personal experience and commonly accepted rules. Objective: This paper investigates the efficacy of applying Eurocodes’ rules for the design and analysis of automated rack supported warehouses. Structural performance, construction feasibility and economic effort are considered. Method: A typical case study building was designed following the two approaches proposed by Eurocodes: elastic and dissipative. Results: The satisfaction of the capacity design requirements, used for dissipative approach, was not always possible. Analyses showed the development of non-uniform collapse mechanisms and yielding patterns. Conclusion: Specific design rules and analysis techniques shall be developed accounting for the structural performance of automated rack supported warehouses.