PSI - Issue 84

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ScienceDirect

Procedia Structural Integrity 84 (2026) 1039–1046

© 2026 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 Conference review under responsibility of the scientific committee of the Conference Keywords: Girder; Strengthening; FRM; CFRP bars; Polypropylene fibers; Innovative materials. Abstract The rehabilitation of historical bridges entails a dual challenge: preserving cultural heritage while ensuring adequate structural performance. This study explores the strengthening of a full-scale bridge girder that had been in service for nearly 90 years and exhibited severe corrosion-induced deterioration, including extensive concrete cover loss and corrosion of both longitudinal reinforcement and stirrups. The experimental program was conducted in two phases. In the first phase, the original girder was subjected to a four-point bending test under displacement control to assess its residual load-bearing capacity, with loading applied well beyond the yielding of the longitudinal reinforcement. In the second phase, an innovative strengthening method was implemented. The retrofit combined two 12 mm carbon fiber–reinforced polymer (CFRP) bars, designed to restore and enhance flexural strength, with a 50 mm fiber-reinforced mortar (FRM) overlay containing polypropylene fibers, intended to improve confinement and crack distribution. The strengthening process is described in detail, with particular focus on surface preparation, bonding mechanisms, and compatibility with the deteriorated substrate. Following the retrofit, the girder was retested under the same loading configuration up to failure. The paper discusses the implementation of the strengthening technique and presents the experimental results, comparing the unstrengthened and strengthened states. The findings demonstrate the effectiveness of hybrid CFRP–FRM systems as a practical and efficient solution for extending the service life of deteriorated bridge elements, while also providing valuable insights into their application on full-scale structural components. III Fabre Conference: Existing Bridges, Viaducts, and Tunnels: Research, Innovation, and Applications Extending the Service Life of Historical Bridges: Experimental Evaluation of a CFRP–FRM Retrofit System Anna Bontempi a, *, Nico Di Stefano a , Fausto Minelli a a Università degli Studi di Brescia, Via Branze 43, Brescia (BS), 25123, Italy

* Corresponding author. E-mail address: anna.bontempi@unibs.it

2452-3216 © 2026 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 Conference 10.1016/j.prostr.2026.06.133