PSI - Issue 78

Available online at www.sciencedirect.com

ScienceDirect

Procedia Structural Integrity 78 (2026) 718–725

© 2025 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 XX ANIDIS Conference organizers Keywords: arch bridge; reinforced concrete; tuned mass damper; seismic retrofit; rebars’ corrosion. Abstract This study explores the effectiveness of low-mass Tuned Mass Dampers (TMDs) for the seismic retrofit of existing reinforced concrete (r.c.) arch bridges. A case study bridge, located in the Valvestino Valley in Northern Italy and designed in the late 1950s by the renowned engineer Riccardo Morandi, is presented. The structure comprises a 90-meter-span box-section arch supporting a 127.7-meter-long deck via spandrel columns. Nonlinear time-history (NLTH) analyses of the existing configuration revealed critical vulnerabilities under Ultimate Limit State (ULS) seismic loading, primarily due to reinforcement corrosion, insufficient shear detailing, and limited ductility. In response, a minimally invasive retrofit strategy was proposed, combining unidirectional bearings and hysteretic dampers in the longitudinal direction, and low-mass TMDs to mitigate transverse motions. A parametric study on the mechanical properties of the TMDs was carried out, revealing that an optimized configuration led to 41.2% reduced piers’ transverse drift together with significantly lower cross- sections’ stresses and strains. The robustness of the solution was confirmed under varying corrosion scenarios and multi-directional seismic inputs. The results confirm the effectiveness of low mass TMDs in enhancing seismic response without altering the structural identity of existing r.c. arch bridges. 1. Introduction Reinforced concrete (r.c.) bridges built in the two decades after the 2 nd world war were designed with rudimental or inadequate seismic provisions compared to those of modern building codes . These include “Maillart - type” arch XX ANIDIS Conference Enhancing the seismic response of a historic r.c. arch bridge by means of low-mass TMDs Samuele Faini a , Emanuele Gandelli a, *, Enrico Faccin a , Luca Facconi a , Fausto Minelli a a Department of Civil, Environmental, Architectural Engineering and Mathematics (DICATAM), University of Brescia, Italy

* Corresponding author. Tel.: +39 0303715968 E-mail address: emanuele.gandelli@unibs.it

2452-3216 © 2025 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 XX ANIDIS Conference organizers 10.1016/j.prostr.2025.12.092