PSI - Issue 44

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

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Procedia Structural Integrity 44 (2023) 1284–1291

© 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. © 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: elastomeric bearings, device stability, full-scale tests, shape factors, large deformation, codes requirements. D ring e rthquake trong mo i ns, anti-se smic d vice are subjected to large horizontal deformation combined t ertical s ress due to gravity loads. For elastomeric bearings, th most widespread technology u ed to this aim, t i necessary to value critic load capacity under this combined effect, to ensure th ir stability in service. In this pap r, elaborations of data from experimental campaign on full-scale rubber bearings (HDRBs) ar compared to results f rm brief theoretical overview, to valuate their stability limits. To examine he effect of d vice geometrical characteriz tion n beari g m chanical behavior, to check instab lity mode and t evaluate the interaction between vertical pressur and shear deformation, three different types of full-scale devices have been considered ( ϕ 500, ϕ 600, ϕ 700). Experimental data refers to “soft” natural rubber bearings, havi a shear modulus G= 0.4MPa (at γ =100%), an equivale t damping factor ξ = 10÷15, primary shape fa tor S 1 varying i th ra e [19,44 – 22,72] and a sec ndary shape factor S 2 varying i the range [2,8÷3,4]. Data derive fr m static shear tests, at increasing l vels of she r strain (up to γ = 250%) combined to g owi g compressiv stress (from 6 MPa to 20 MPa). Th ir laboration has been ac ompanied by the use of dimensionle s factors, n partic r the ratio γ /S 2 , that r sults an ffective design parameter to describe bearing performa ce. On the base f analytical formul ti ns f om literat re, the exper ment l results have bee matche w th theor tical evaluations of the critical load. The experimental occurrence of buckling instability has been read also in light of design guidelines provided for rubber devices. © 2022 The Authors. Published by ELSEVIER B.V. This is an ope acces article under CC BY-NC-ND lic nse ( https://creativec mmo s.org/licenses/by-nc-nd/4.0 ) P er-review under responsibility of the scientific committee of the XIX ANIDIS Conferenc , Seismic Engineering in Italy Keywords: elastomeric bearings, device stability, full-scale tests, shape factors, large deformation, codes requirements. During earthquake strong motions, anti-seismic devices are subjected to large horizontal deformations combined to vertical stress due to gravity loads. For elastomeric bearings, the most widespread technology used to this aim, it is necessary to value critical load capacity under this combined effect, to ensure their stability in service. In this paper, elaborations of data from experimental campaign on full-scale rubber bearings (HDRBs) are compared to results form a brief theoretical overview, to evaluate their stability limits. To examine the effect of device geometrical characterization on bearing mechanical behavior, to check instability mode and to evaluate the interaction between vertical pressure and shear deformation, three different types of full-scale devices have been considered ( ϕ 500, ϕ 600, ϕ 700). Experimental data refers to “soft” natural rubber bearings, having a shear modulus G= 0.4MPa (at γ =100%), an equivalent damping factor ξ = 10÷15, a primary shape factor S 1 varying in the range [19,44 – 22,72] and a secondary shape factor S 2 varying in the range [2,8÷3,4]. Data derive from static shear tests, at increasing levels of shear strain (up to γ = 250%) combined to growing compressive stress (from 6 MPa to 20 MPa). Their elaboration has been accompanied by the use of dimensionless factors, in particular the ratio γ /S 2 , that results an effective design parameter to describe bearing performance. On the base of analytical formulations from literature, the experimental results have been matched with theoretical evaluations of the critical load. The experimental occurrence of buckling instability has been read also in light of design guidelines provided for rubber devices. XIX ANIDIS Conference, Seismic Engineering in Italy Stability issues for elastomeric bearings: analytical formulations compared to experimental results Laura Giovanna Guidi a *, Giuseppe Brandonisio a , Antonello De Luca a a Dept. of Structures for Engineering and Architecture, University of Naples Federico II, , Piazzale Tecchio 80, 80125 Naples, Italy XIX ANIDIS Conference, Seismic Engineering in Italy Stability issues for elastomeric bearings: analytical formulations compared to experimental results Laura Giovanna Guidi a *, Giuseppe Brandonisio a , Antonello De Luca a a Dept. of Structures for Engineering and Architecture, University of Naples Federico II, , Piazzale Tecchio 80, 80125 Naples, Italy Abstract Abstract

* Corresponding author. E-mail address: lauragiovanna.guidi@unina.it * Correspon ing author. E-mail address: lauragiovanna.guidi@unina.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 © 2022 The Authors. Published by ELSEVIER B.V. This is an open access article under th CC BY-NC-ND license (https://creativecommons.org/licens s/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.2023.01.165