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) 1356–1363

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

© 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 The non-linear out of plane dynamical response of the masonry wall, suitably reinforced at the top and hit by sequences of acceleration pulses, alternating in sign and with different intensity and duration, is the subject of the paper. The wall moves out of its plane with a gradually changing failure mechanism and two relevant aspects characterize this motion: the occurrence of a rotational build up under the action of the pulse sequence, in spite of their alternating in sign and the occurrence of the dynamical collapse. This last takes place when, under the second last pulse of the sequence, the increasing mechanism has reached the critical configuration in which all resistance of the wall is lost. The arriving of the last pulse, pushing the wall to further increase its rotation, yields the collapse. The ratio between the dynamical and the statical collapse accelerations – the so-called strength reduction or performance factors – is thus directly determined following the dynamical response of the wall to the pulse sequences. The paper, which is part of an ongoing research (Coccia et al. 2022) reveals how the wall, so vulnerable under the out of plane seismic actions, can mobilize collapse mechanisms capable of defending it by the destructive action of the quakes. Abstract The non-linear out of plane dynamical response of the masonry wall, suitably reinforced at the top and hit by sequences of accelera ion pulses, alternating in sign and with different intensity and duration, is the subject of the paper. The wall moves out of its plane with a gradually changing failure mechanism and two relevant aspects characterize this motion: the occurrence of a rotational build up under th action of the pulse quenc , in pite of their al ernating in sign nd the ccurrence of th dy amical collapse. This la t takes pl ce when, under the second last pulse of the sequence the increasing mechanism has reached th critical configuration in which resistance o the wall is lost. The arriving of the last ulse, pushing the wall to further increase its rotation, yields the col apse. Th ratio between t e dynamical and the statical collaps accelerations – the so-called str ngth re uction or performance factors – is thus directly determined following th dynamical respons of the wall to t e pulse sequenc s. The paper, which is part of an ongoing re e r h (Coccia et al. 2022) r veals how t wall, so vulnerable under the o t of pla e seismic actions can mobilize collapse mechanisms capable of defending it by the destructive action of the quakes. Keywords: masonry reinf rced wall; seismic analysis; rocking; pulse; force reduction factor 1. Introduction The paper analyses the dynamical response of the masonry wall, suitably reinforced, hit by a sequence of horizontal acceleration pulses acting orthogonally to its plane. It represents the top floor façade wall, the most vulnerable structural component of the masonry building under seismic actions. The motion of the masonry wall starts when the seismic actions reach a level for which cracks form, giving rise to a mechanism. XIX ANIDIS Conference, Seismic Engineering in Italy Dynamical assessment of the performance factor “Q” for the masonry wall under the out of plane seismic action Simona Coccia a, *, Mario Como a a DICII – University of Rome “Tor Vergata”, Via del Politecnico 1, 00133 Rome (Italy) XIX ANIDIS Conference, Seismic Engineering in Italy Dynamical assessment of the performance factor “Q” for the masonry wall under the out of plane seismic action Simona Coccia a, *, Mario Como a a DICII – University of Rome “Tor Vergata”, Via del Politecnico 1, 00133 Rome (Italy) Keywords: masonry reinforced wall; seismic analysis; rocking; pulse; force reduction factor 1. Introduction The paper analyses the dynamical response of the masonry wall, suitably reinforced, hit by a sequence of horizontal acceleration pulses acting orthogonally to its plane. It represents the top floor façade wall, the most vulnerable structural component of the masonry building under seismic actions. The motion of the masonry wall starts when the seismic actions reach a level for which cracks form, giving rise to a mechanism.

* Corresponding author. Tel.: +39-06-72597076 E-mail address: coccia@ing.uniroma2.it

* Corresponding author. Tel.: +39-06-72597076 E-mail address: coccia@ing.uniroma2.it

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.2023.01.174 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