PSI - Issue 44

ScienceDirect Available online at w w.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com Procedia Structural Integrity 44 (2023) 870–877 Structural Integrity Procedia 00 (2022) 000 – 000

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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.2023.01.113 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 1. Introduction The vulnerability of the existing building stock is a substantial economic and social problem, and the demand for retrofitting develops as existing structures age and decay (Beschi et al. (2015), Marino et al. (2019), Lima et al. (2018)). Recent earthquakes in Italy (herein: Molise 2002, L’Aquila 2009, Emilia 2012, Central I taly 2016-2017) as well as in 2452-3216 © 2022 The Author . 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 Post-earthquake observations have shown that poorly reinforced concrete (RC) beam-column joints in existing structures determine premature brittle failures during seismic action. Failure of these critical parts, which transfer stresses and moments between beams and columns, resulted in the catastrophic collapse of structures in low to moderate seismic risk zones. Exterior (i.e. corner or façade) beam-column joints of buildings constructed without or with insufficient transverse reinforcements are commonly involved in the failur . T e purp se of th s study was to investigate th ef ective vulnerability of two fu l-scale ex erior façade beam-column joi ts under ransvers cyclic loading. Both the specimen design strat gy and the test setup were conceived to emphasize th vulnerability of the joints and, th refore, to achieve shear f ilure in the joint panel prior to yielding both beam and column reinforcements un r the simu ated seismic action. In particular: (i) joint was characterized by he abs nc of any apaci y design principle (i.e. total lack of stirrups in the joint panel) to highlight structural d fici ncies typical of he 1960s-70s Italian construction pr cti e; (ii) beam a columns w re adequately designed to remain in the ela ic field during he t sts; (iii) the sp cimen was ev luated in the absence axial load. In this w rk, he exp rimental seismic performance is compared to the one pr dicted by code/lit ratu e odels. The est is then simulated using a umerical three-d mension l model for mod lling rack prop g tion and fracture in concrete using the smeared crack technique. The model also allowe for a more comprehensive examination of the effects f certain assumption o the mechanical performance of th RC joint during the experiment. Keywords: Reinforced C ncrete; Joint; Heritage; S ic behavior; Beam-colu n joints; Cyclic load 1. Introduction The vulnerability of the existing building stock is a substantial economic and social problem, and the demand for retrofitting develops as existing structures age and decay (Beschi et al. (2015), Marino et al. (2019), Lima et al. (2018)). Recent earthquakes in Italy (herein: Molise 2002, L’Aquila 2009, Emilia 2012, Central I taly 2016-2017) as well as in © 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 Post-earthquake observations have shown that poorly reinforced concrete (RC) beam-column joints in existing structures determine premature brittle failures during seismic action. Failure of these critical parts, which transfer stresses and moments between beams and columns, resulted in the catastrophic collapse of structures in low to moderate seismic risk zones. Exterior (i.e. corner or façade) beam-column joints of buildings constructed without or with insufficient transverse reinforcements are commonly involved in the failure. The purpose of this study was to investigate the effective vulnerability of two full-scale exterior façade beam-column joints under transverse cyclic loading. Both the specimen design strategy and the test setup were conceived to emphasize the vulnerability of the joints and, therefore, to achieve shear failure in the joint panel prior to yielding both beam and column reinforcements under the simulated seismic action. In particular: (i) joint was characterized by the absence of any capacity design principle (i.e. total lack of stirrups in the joint panel) to highlight structural deficiencies typical of the 1960s-70s Italian construction practice; (ii) beams and columns were adequately designed to remain in the elastic field during the tests; (iii) the specimen was evaluated in the absence of axial load. In this work, the experimental seismic performance is compared to the one predicted by code/literature models. The test is then simulated using a numerical three-dimensional model for modelling crack propagation and fracture in concrete using the smeared crack technique. The model also allowed for a more comprehensive examination of the effects of certain assumptions on the mechanical performance of the RC joint during the experiment. Keywords: Reinforced Concrete; Joint; Heritage; Seismic behavior; Beam-column joints; Cyclic load XIX ANIDIS Conference, Seismic Engineering in Italy Structural performance of unreinforced full-scale façade concrete beam-column joint under cyclic load Michele Angiolilli a , Amedeo Gregori b* , Roberto Tonelli c , Claudio Tonelli c , Edoardo Ciuffetelli b , Alfredo Peditto b a Laboratori Nazionali del Gran Sasso - INFN, 67100 L’Aquila, Italy b Dipartimento di Ingegneria Civile, Edile e Architettura, Università dell’Aquila, 67100 L’Aquila, Italy c Tonelli Consulting S.r.l., 67051 Avezzano, Italy XIX ANIDIS Conference, Seismic Engineering in Italy Structural performance of unreinforced full-scale façade concrete beam-column joint under cyclic load Michele Angiolilli a , Amedeo Gregori b* , Roberto Tonelli c , Claudio Tonelli c , Edoardo Ciuffetelli b , Alfredo Peditto b a Laboratori Nazionali del Gran Sasso - INFN, 67100 L’Aquila, Italy b Dipartimento di Ingegneria Civil , Edile e Architettura, Università dell’Aquila, 67100 L’Aquila, Italy c Tonelli Consulting S.r.l., 67051 Avezzano, Italy