PSI - Issue 44

ScienceDirect Available online at www.sciencedirect.com ScienceDirect 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 Procedia Structural Integrity 44 (2023) 1076–1083

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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.2023.01.139 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 Existing reinforced concrete buildings, characterized by high seismic vulnerability, constitute a significant part of the existing building heritage, especially in Europe (Eurostat 2001). The high seismic vulnerability of the existing reinforced concrete buildings is connected to the durability of the materials used and the deficiencies deriving from a seismic design based on inadequate criteria concerning the performance requirements demanded by the latest generation of Italian technical code (NTC2018) in combination with the increase in expected seismic intensity, introduced by recent seismic hazard maps. In recent years, multiple methodologies have been developed to mitigate 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. r /licenses/ y-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the XIX ANIDIS Conference, Seismic Engineering in Italy Abstract Usually, the works for seismic improvement do not allow the use of the building. The interruption of use in many cases is not allowed especially for buildings with strategic or public service functions. In recent years, an alternative approach to intervention has spread that allows operating exclusively outside the structure through the use of a technology called a structural exoskeleton. The exoskeleton in many cases consists of a bi-dimensional or three-dimensional truss steel structure. The goal of this technology is to transfer most part the seismic action to the external structure. This allows for avoiding reinforcements to the existing structure. for the building-exoskeleton system to be effective against seismic action, the exoskeleton must be sufficiently stiff and the coupling device between the two structures must not produce internal constraints and generate unwanted stresses for the existing structural elements. A critical aspect of the application of this technology is the transfer of the floor seismic forces from the existing structure to the exoskeleton. The present work illustrates the study of an innovative building-exoskeleton coupling device to transfer the seismic shear forces of the floor from the existing structure to the exoskeleton without generating in-plane and out-of-plane bending interactions. The study of the coupling device was carried out as part of the seismic improvement project of a real case study. The seismic improvement project involves the construction of external shear walls consisting of steel trusses. The results of nonlinear numerical analyses on the global models of the building-exoskeleton systems as well as the results of local numerical analyses of the coupling device are illustrated. Keywords: Exoskeleton , seismic improvement , seismic vulnerability. 1. Int oduction Existing reinforced concrete buildings, characterized by high seismic vulnerability, constitute a significant part of the existing building heritage, especially in Europe (Eurostat 2001). The high seismic vulnerability of the existing reinforced concrete buildings is connected to the durability of the materials used and the deficiencies deriving from a seismic des gn based on inadequate criteri conc rning the p rformance equ rement dem nded by the la est gen ratio of Italian t chnical code (NTC2018) in combination with the incr a e in exp cted seismic intens ty, introdu by recent seismic hazard maps. In recent years, multiple m thodologies have be n d veloped to mitigate © 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 Usually, the works for seismic improvement do not allow the use of the building. The interruption of use in many cases is not allowed especially for buildings with strategic or public service functions. In recent years, an alternative approach to intervention has spread that allows operating exclusively outside the structure through the use of a technology called a structural exoskeleton. The exoskeleton in many cases consists of a bi-dimensional or three-dimensional truss steel structure. The goal of this technology is to transfer most part the seismic action to the external structure. This allows for avoiding reinforcements to the existing structure. for the building-exoskeleton system to be effective against seismic action, the exoskeleton must be sufficiently stiff and the coupling device between the two structures must not produce internal constraints and generate unwanted stresses for the existing structural elements. A critical aspect of the application of this technology is the transfer of the floor seismic forces from the existing structure to the exoskeleton. The present work illustrates the study of an innovative building-exoskeleton coupling device to transfer the seismic shear forces of the floor from the existing structure to the exoskeleton without generating in-plane and out-of-plane bending interactions. The study of the coupling device was carried out as part of the seismic improvement project of a real case study. The seismic improvement project involves the construction of external shear walls consisting of steel trusses. The results of nonlinear numerical analyses on the global models of the building-exoskeleton systems as well as the results of local numerical analyses of the coupling device are illustrated. XIX ANIDIS Conference, Seismic Engineering in Italy Shear devices coupling exoskeleton and existing RC buildings for seismic improvement Fabrizio Comodini a , Alessando Fulco b, Marco Mezzi b a University eCampus,Novedrate (CO) 22060, Italy b Civil and environmental engineering department, University of Perugia , Perugia 06125, Italy XIX ANIDIS Conference, Seismic Engineering in Italy Shear devices coupling exoskeleton and existing RC buildings for seismic improvement Fabrizio Comodini a , Alessando Fulco b, Marco Mezzi b a University eCampus,Novedrate (CO) 22060, Italy b Civil and environmental engineering department, University of Perugia , Perugia 06125, Italy Keywords: Exoskeleton , seismic improvement , seismic vulnerability.