PSI - Issue 44

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2022) 000–000 Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia

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Procedia Structural Integrity 44 (2023) 2318–2325

XIX ANIDIS Conference, Seismic Engineering in Italy On the seismic response of rack structures affected by pinching Alessandro Mei * , Maurizio Orlando, Luca Salvatori *

A

Department of Civil and Environmental Engineering of Florence, Via di S. Marta, 3 – 50139, Firenze, Italy

© 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy. Abstract The nonlinear static and dynamic behavior of rack structures affected by joint pinching are studied using a simplified single-degree of-freedom system. Since the joints of steel rack structures play a crucial role in the capacity design methodology, as they are the main source of energy dissipation, their behavior is widely studied in the literature, highlighting their reduced hysteresis loop. However, no systematic study investigates and associates these characteristics with a possible increase in displacement demand. Using a single-degree-of-freedom system focuses attention on the type of cyclic behavior and allows a comparison of linear and nonlinear responses, the latter evaluated using both elastic-plastic and pinching laws. At prescribed ductility, the elastic-plastic and pinching responses can be compared with the prescriptions of Italian and European building codes. This simplified method was also applied to case studies of experimental pushover tests on racks found in the literature. Results showed that neglecting the joint pinching behavior for a rack structure can lead to an underestimation of the displacement demand in the case of the application of the nonlinear static seismic analysis method and hence to the overestimation of the q-factor for the application of linear seismic analysis methods. © 2022 The Authors. Published by ELSEVIER B.V. This is an open-access article under the CC BY-NC-ND license ( https://creativecommons.org/licenses/by-nc-nd/4.0 ) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy Keywords: Racks; Steel Structures; Pinching; Steel Joints; Pushover Analysis; Force reduction factor. 1. Introduction In recent years, the use of steel racks and steel rack warehouses increased thanks to their lightness, fast assembly, and relative economic benefits. Rack structures are made of cold-formed steel and usually, structural schemes used in the calculation are simple: frame with semi-rigid joints in the down-aisle direction and truss in the cross-aisle direction. 1. Introduction

* Corresponding author. E-mail address: alessandro.mei@unifi.it

2452-3216 © 2022 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy

2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy. 10.1016/j.prostr.2023.01.296