PSI - Issue 44

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

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Procedia Structural Integrity 44 (2023) 590–597

XIX ANIDIS Conference, Seismic Engineering in Italy XIX ANIDIS Conference, Seismic Engineering in Italy

Validation of a New Equation to Estimate the Yield Strength of Lead Rubber Bearings Masoud Pourmasoud a, *, Alan R. L. Park b , Iman Hajirasouliha c , James Lim a , Amirmahmoud Behzadi d Validation of a New Equation to Estimate the Yield Strength of Lead Rubber Bearings Masoud Pourmasoud a, *, Alan R. L. Park b , Iman Hajirasouliha c , James Lim a , Amirmahmoud Behzadi d

a Department of Civil and Environmental Engineering, University of Auckland, New Zealand b Low Damage Design Company, New Zealand c Department of Civil Engineering, The University of Sheffield, UK d Department of Civil Engineering, Shomal University, Iran a Department of Civil and Environmental Engineering, University of Auckland, New Zealand b Low Damag Design Company, New Zealand c Department of Civil Engineering, The University of Sheffield, UK d Department of Civil E gineering, Shomal University, Iran

Abstract Abstract

© 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. The design of seismic isolators as specified by building code requirements is well defined and well established. However, there is still some refinement required for these design practices, especially in terms of estimating the yield strength and confinement of lead cores. The Lead Core is a key component in a Lead Rubber Bearing (LRB) that provides energy absorption resulting in the damping of a unit/system. Historically, designers have used a standard value for lead yield (7-10 MPa) depending on individual preferences. However, based on prototype test results, it has been shown that lead yielding is variable and strongly influenced by a number of physical parameters. This piece of research has focused on validating a newly developed equation to estimate the yield strength of lead rubber bearing regarding the confinement category of the lead cores. The yield strength results from prototype tests were compared with the predicted yield strengths from the proposed equation. The output trends present an appropriate match between the prototype test and the proposed equation so that the difference for most cases falls within ±5%. © 22 h LSEVIER B.V. T i i p c e rti le u r t e CC li tt s://creativecom ons.org/licens s/by-nc-nd/4.0)Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in ItalyKeywords: RC beam-column joints; nonlinear analysis; rotational springs; seismic capacity Keywords : Seismic Isolation; Lead Core; Yield Strength; Confinement Category. The design of seismic isolators as specified by building code requirements is well defined and well established. However, there is still some refinement required for these design ractices, especially in terms of estimating the yield strength and confinem nt of lead cores. The Lead Cor is a key component in a Lead Rubber Bearing (LRB) that provides energy absorption resulting in the damping of a unit/system. Historically, designers have used a standar value for lead yield (7-10 MPa) depending on individual preferences. However, based on prototype test results, it has be n s own that lead yiel ing is variable and strongly influenced by a number of physical parameters. This piece f research has focused on v lidati g a newly developed equation to estimate the yield strength of le d rub er bearing regarding the confinement cat gory of the lead cores. The yield strength results from prot type tests w re compared wit the predicted yield strengths from the proposed equation. The output trends present an appropriate match between th prototyp test and the proposed quation so that the difference for most cases falls wit in ±5%. © 2022 The Authors. Publis ed 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 th cientific committee of the XIX ANIDIS Conference, Seismi Enginee ing in ItalyKeywords: RC beam-column joints; nonli ear analysis; rotational springs; s ismic capacity Keywords : Seismic Isolation; Lead Core; Yi ld Strength; Confinement Category.

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* Corresponding author. Tel.: +64-27-388-5463. E-mail address: mpou570@aucklanduni.ac.nz * Corresponding author. Tel.: +64-27-388-5463. E-mail address: mpou570@aucklanduni.ac.nz

1. Introduction 1. Introduction

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.2023.01.077 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 Seismic isolation systems have become commonplace worldwide due to their effectiveness in providing a low damage design solution for a variety of structures including ‒ but not restricted to ‒ hospitals, schools, nuclear power plants, control towers, and retrofitting of existing buildings (Whittaker 2019; Clemente and Martelli 2019; Jampole et al. 2020; Xie et al. 2022). Code compliant buildings are generally designed for a specific earthquake tolerance although more significant events are possible, which can escalate the accelerations imparted on the building and affect the content’s performance (FEMA 2018; FEMA 2007; Whittaker 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 u der responsibility of t scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy Seismic isolation systems have become commonplace worldwide due to their effectiveness in providing a low damage design solution for a variety of structures in luding ‒ but ot restricte to ‒ hospitals, schools, nuclear power plants, c ntrol towers, and retrofitting of existing buildings (Whittaker 2019; Clemente and Martelli 2019; Jampole et al. 2020; Xie et al. 2022). Code complia t buildings are generally designed for a specific earthquake tolerance although m re significant events are possible, which an esc late the accelerations imparted on the building and affect the conte t’s performance (FEMA 2018; FEMA 2007; Whittaker