PSI - Issue 84

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ScienceDirect

Procedia Structural Integrity 84 (2026) 944–951

III Fabre Conference: Existing Bridges, Viaducts, and Tunnels: Research, Innovation, and Applications Fire analysis of seismically isolated bridges with

prestressed concrete deck Fabio Mazza a, *, Ciriaco Marino a a Department of Civil Engineering, University of Calabria, Ponte P. Bucci, 87036 Rende (Cosenza), Italy

© 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 Keywords: Seismic isolation; Prestressed concrete deck; Vehicle collisions; Fire scenarios; Thermal analysis. Abstract Isolation at the deck level is a widely used technique in the Italian bridge network to improve the seismic performance of bridges with prestressed concrete (PC) deck. The significant increase of vehicle collisions involving bridges of critical transport infrastructures leads to fuel burning in an open fire compartment, that induces fires characterized by high temperatures within the first few minutes of fire initiation. Severe fire vulnerability can be observed in prestressing strands of PC decks, with low fire resistance due to the high-tension stress, and elastomeric (e.g. high-damping-laminated-rubber bearings, HDRBs) isolators, when temperatures exceed the point at which vulcanization between layers of rubber and steel plates occurs. Aim of this work is to analyse thermal response of seismically isolated bridges with prestressed concrete deck subjected to the most probable fire scenarios. The heat release rate curves for different types of vehicles (i.e. bus, heavy goods vehicle, fuel track, car and motorcycle) are selected, also considering multiple collisions on the assumption that that all vehicles involved ignite simultaneously. A simply supported bridge with PC deck is designed in line with the Italian code in a high-risk seismic zone, assuming three spans of equal length supported by two RC abutments and two frames constituted of four RC circular piers. Eight identical HDRBs are inserted on the top of the piers as support of four PC beams, equally spaced apart, and a RC slab. Natural fire curves for different combinations of vehicles are obtained using the zone model of the CFAST software, assuming two fire locations in the central span of the bridge: i.e. at the centre, both longitudinally and transversely; adjacent to the RC pier and transversely centred. Finally, fire fragility curves of the bridge are obtained using thermo-mechanical results obtained using the SAFIR software and the Bayesan cloud analysis.

* Corresponding author. Tel.: +39-0984-496908; fax: +39-0984-494045. E-mail address: fabio.mazza@unical.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.2026.06.121