PSI - Issue 44

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

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 44 (2023) 442–449

© 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 When performing the seismic analysis of existing unreinforced masonry buildings, flexible diaphragms are often present. In case the flexibility of these elements is particularly significant, the execution of meaningful pushover analyses with fixed load pattern, performed on a three-dimensional model of the structure, is widely recognized to be problematic and tends to provide information only on the failure condition of the weakest wall. Thus, single bidimensional models of each structural wall are usually required and separated pushover analyses are carried out on each of them. In this paper, different modelling strategies to model single walls and entire buildings to perform nonlinear seismic analysis, are compared. In particular, simplified approaches included in current building codes are compared with more refined approaches, to find out the main differences among code compliant and advanced models and highlight possible weaknesses of code-compliant strategies. © 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: unreinforced masonry; nonlinear analysis; equivalent-frame models; wall analysis; flexible floors 1. Introduction When dealing with existing unreinforced masonry (URM) buildings, flexible diaphragms are often present. In case the flexibility of these elements is particularly significant, the seismic analysis by means of pushover analyses with fixed load pattern, performed on a three-dimensional model of the structure, is widely recognized to be problematic and tends to provide information only on the failure condition of the weakest wall. For this reason, XIX ANIDIS Conference, Seismic Engineering in Italy Comparison of refined and code-compliant modelling strategies for the seismic analysis of unreinforced masonry buildings Stefano Bracchi a *, Maria Rota b , Andrea Penna c a Dept. of Buildings and Infrastructures, EUCENTRE Foundation, Via Ferrata 1, 27100 Pavia, Italy b Dept. of I dustrial Products, EUC NTRE Foundation, Via Ferrata 1, 27 00 Pavia, Italy c Dept. of Civil Engineering and Architecture, University of Pavi , Via Ferrata 3, 27100 Pavia, Italy Abstract When performing the seismic analysis of existing unreinforced masonry buildings, flexible diaphragms are often present. In case the flexibility of thes le ents is particularly si nifica t, th execution of mea ing ul pushover analy es with fixed load pattern, performed on a thr e-di sional model of the structur , is widely recognized to be problematic and ten s to rovide information only on the failure condition of the weakes wall. Thus, single bidimensional m dels of each s ructural wall ar usually required and separ ted pushover analyses ar carried out on each of them. In th s p per, ifferent modelling strategies to mode single walls and entir buildings to perform nonlinear seismic nalysis, are compared. In particular, simp ified approaches included in current building codes are c mpared with more r fined pproaches, t find out the main differences among cod - compliant and advanced models and highlight possible weaknesses of code-compliant strategies. © 2022 The Authors. Publish d 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 re ponsibility of scientific committe of the XIX ANIDIS C nfere ce, Seismic Engineering in Italy Keywords: unreinforced masonry; nonlinear analysis; equivalent-frame models; wall analysis; flexible floors 1. Introduction When dealing with existing unreinforced masonry (URM) buildings, flexible diaphragms are often present. In case t flexibility of these eleme ts is particul rly significant, the seismic analysis by mean of pushover analyses with fixed load pattern, performed on three-dimens on l model of the structure, is widely recognized to be problematic an tends to rovide inf rmation only o the failure condi ion of the weakest wall. F r this reason, XIX ANIDIS Conference, Seismic Engineering in Italy Comparison of refined and code-compliant modelling strategies for the seismic analysis of unreinforced masonry buildings Stefano Bracchi a *, Maria Rota b , Andrea Penna c a Dept. of Buildings and Infrastructures, EUCENTRE Foundation, Via Ferrata 1, 27100 Pavia, Italy b Dept. of Industrial Products, EUCENTRE Foundation, Via Ferrata 1, 27100 Pavia, Italy c Dept. of Civil Engineering and Architecture, University of Pavia, Via Ferrata 3, 27100 Pavia, Italy

* Corresponding author. Tel.: +39 0382-5169843 E-mail address: stefano.bracchi@eucentre.it * Corresponding author. Tel.: +39 0382-5169843 E-mail address: stefano.bracchi@eucentre.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 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.2023.01.058