PSI - Issue 44

Agnese Natali et al. / Procedia Structural Integrity 44 (2023) 2326–2333 Agnese Natali, Francesco Morelli / Structural Integrity Procedia 00 (2022) 000–000

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4. Conclusions In this paper, a novel design approach—named “Plastic Ovalization admitted Strategy”—with experimental validation for seismic resistant Automated Rack Supported Warehouses (ARSWs) is presented. This new method is based on concentrating dissipation in diagonal-to-upright connections through the plastic ovalization of the connection holes. The core of the approach is the design of the connection, with capacity rules that prevent other fragile failures in the connection itself, and of all the other elements, which shall be over-resistant with respect to the connection. After the numerical assessment of the performance of ARSWs structures designed with this new approach, an experimental campaign is carried out to evaluate resistance, failure mode and plastic deformation capacity of the connection for different positions of the bolt. An additional hole is added in the inner side of the diagonal to limit and control the bearing resistance in compression (to drive plastic deformations in the diagonal only, not in the upright). The tests show that if the approach is correctly applied (upright / brace / connection / material choice), the response is characterized by an appropriate ductile behaviour, with plastic deformations developing mainly in the two ends of the diagonals. Indeed, the adopted design rules seems to prevent other fragile failures of the connections and other mechanisms in diagonal and upright elements. Besides, the geometrical parameters (distance of the outer hole from the free edge e1, distance between the two holes p1) can be used to obtain the desired hierarchy among bearing in tension/compression of the diagonal and bearing of upright. Further tests, executed on different types of cross sections, are needed to study the influence of the geometrical and mechanical properties on the proposed strategy. Moreover, the assessment of the performance of the whole structure and the final definition of the behaviour and over-strength factors are still needed. The research conducted was carried out in the STEELWAR research project, funded by the European Commission, Research Fund for Coal and Steel (Grant Agreement No.754102), which is gratefully acknowledged. References Bozorgnia, Y., Atik, L., Ancheta, T., Atkinson, G., Baker, J., Baltay, A., Boore, D., et al., 2014. NGA-West2 research project. Earthquake Spectra. ECCS “Recommended testing procedure for assessing the behaviour of structural steel elements under cyclic loads,” 1986. . EN 1993-1-3:2006 Eurocode 3: Design of steel structures - Part 1-3: General rules - Supplementary rules for cold-formed members and sheeting, 2006. . EN 1998-1:2004: Eurocode 8: Design of structures for earthquake resistance – Part 1: General rules, seismic actions and rules for buildings., 2004. . Haque, A. B. M. R., and Alam, M. S., 2015. Preliminary Investigation on the Overstrength and Force Reduction Factors for Industrial Rack Clad Buildings. Jalayer, F., and Cornell, C. A., 2009. Alternative non-linear demand estimation methods for probability-based seismic assessments. Earthquake Engineering & Structural Dynamics, 38(8), 951–972. DOI: 10.1002/eqe.876 Mazzoni, 2017. The open system for earthquake engineering simulation (OpenSEES) user command-language manual. Natali, A., Morelli, F., and Salvatore, W., 2022a. On the Seismic Design and Behavior of Automated Rack Supported Warehouse. DOI: 10.21203/rs.3.rs-1577721/v1 Natali, A., Morelli, F., and Salvatore, W., 2022b. Seismic performance of currently designed Automated Rack Supported Warehouses. 7h World Congress on Civil, Structural, and Environmental Engineering (CSEE’22). Natali, A., Morelli, F., and Salvatore, W., 2022c. Influence of the Design Parameters on the Current Seismic Design Approach for Automated Rack Supported Warehouses. DOI: 10.11159/icsect22.202 Tsarpalis, D., 2022. “Ductile Seismic Design, Performance Assessment, and Taxonomic Characterization of Steel Racking Systems”, Doctoral Thesis, National Technical University of Athens, Institute of Steel Structures. Tsarpalis, D., Vamvatsikos, D., Delladonna, F., Fabini, M., Hermanek, J., Margotan, P., Sesana, S., et al., 2022. Macro-characteristics and taxonomy of steel racking systems for seismic vulnerability assessment. Bulletin of Earthquake Engineering. Tsarpalis, D., Vamvatsikos, D., Vayas, I., and Delladonna, F., 2021. Simplified Modeling for the Seismic Performance Assessment of Automated Rack-Supported Warehouses. Journal of Structural Engineering, 147.