PSI - Issue 70

Umeshkumar T. Mourya et al. / Procedia Structural Integrity 70 (2025) 35–42

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4. Summary and Conclusion This paper presents experimentally evaluated looseness in boltless beam-to-upright connections in cold-formed steel storage racks, a critical but often overlooked parameter in structural performance of racks. Using a single cantilever bending test setup, twelve different connection configurations were tested to quantify looseness under reversal loading. The results revealed significant variability in looseness values, ranging from 0.005 to 0.028 radians, corresponding to imperfection amplitudes between 1/200 and 1/35. These variations are influenced by beam depth, number of tabs in the end-connector, and upright thickness. A key observation is that even minor changes in geometry, particularly in upright thickness and tab clearances, can lead to substantial differences in the connection looseness. This highlights the necessity of explicitly accounting for looseness in analytical and numerical models, especially in the design of pallet racking systems subject to seismic or dynamic loads. The outcomes of this study emphasize that design codes and simulation practices should incorporate looseness as a critical input parameter. References Bernuzzi, C., & Castiglioni, C. A., 2001. Experimental analysis on the cyclic behaviour of beam-to-column joints in steel storage pallet racks. Thin Walled Structures, 39(10), 841–859. Dumbrava, F., & Cerbu, C., 2022. Effect of the Looseness of the Beam End Connection Used for the Pallet Racking Storage Systems, on the Mechanical Behavior of the Bearing Beams. Materials, 15,4278. CEN (2020). EN15512: Steel Static Storage Systems -Adjustable Pallet Racking Systems - Principles for Structural Design Gusella, F., Lavacchini, G., & Orlando, M., 2018. Monotonic and cyclic tests on beam-column joints of industrial pallet racks. Journal of Constructional Steel Research, 140, 92–107. Jovanović, Đ., Žarković, D., Vukobratović, V., & Brujić, Z. , 2019. Hysteresis model for beam-to-column connections of steel storage racks. Thin Walled Structures, 142(May), 189–204. Markazi, F. D., Beale, R. G., & Godley, M. H. R., 1997. Experimental analysis of semi-rigid boltless connectors. Thin-Walled Structures, 28(1), 57–87. Mohan, V., Prabha, P., Rajasankar, J., Iyer, N. R., Raviswaran, N., Nagendiran, V., & Kamalakannan, S. S. , 2015. Cold-formed steel pallet rack connection: an experimental study. International Journal of Advanced Structural Engineering, 7(1), 55 –68. Mourya, U. T., & Jayachandran, S. A., 2024. Moment-rotation model for a range of beam-to-upright connections in cold-formed steel storage racks. Structures, 66, 106842. Prabha, P., Marimuthu, V., Saravanan, M., & Arul Jayachandran, S. , 2010. Evaluation of connection flexibility in cold formed steel racks. Journal of Constructional Steel Research, 66(7), 863–872. RMI. (2019). Specification for the Design, Testing, and Utilization of Industrial Steel Storage Racks. Rack Manufacturers Institute, Inc. Shah, S. N. R., Sulong, N. H. R., Jumaat, M. Z., & Shariati, M. , 2016. State-of-the- art review on the design and performance of steel pallet rack connections. Engineering Failure Analysis, 66, 240–258. Zhao, X., Wang, T., Chen, Y., & Sivakumaran, K. S. , 2014. Flexural behavior of steel storage rack beam-to-upright connections. Journal of Constructional Steel Research, 99, 161–175.