PSI - Issue 84

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ScienceDirect

Procedia Structural Integrity 84 (2026) 615–622

© 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: Bridge assessment; traffic loading; traffic simulation; probabilstic models. Abstract Structural verifications result from a combination of load effects and resistance. While a great deal of research has focussed on the resistance side, the load side has received less attention. In fact, structures like highway bridges are subjected to greatly variable loads, particularly the traffic loading. It is then apparent that existing bridges would benefit from the use of site-specific traffic loads, rather than the conservative loads conceived at the design stage. This paper presents a methodology to derive traffic loads from site-specific traffic data within the framework of the Italian guidelines on existing highway bridges. Traffic micro-simulation is a versatile tool to generate realistic traffic scenarios, particularly the congested conditions which govern long-span bridges. The simulation outcome is then extrapolated to find a site-specific characteristic traffic loading value. Finally, load effects based on real traffic data are computed for a sample 50-m-long bridge, resulting in considerably reduced loads compared to the Eurocode Load Model 1. The presented approach may well spare many existing bridges from unnecessary restrictions or interventions. 1. Introduction Bridges are an essential part of any transportation network and are built primarily to carry traffic. However, the highway traffic loading is greatly variable, depending on several factors like the economic development of the area. III Fabre Conference: Existing Bridges, Viaducts, and Tunnels: Research, Innovation, and Applications The use of traffic data for structural assessment in compliance with the Italian guidelines on existing bridges Alessandro Lipari a * a ENEA Italian National Agency for New Technologies, Energy and Sustainable Economic Development, SS7 Via Appia km 706, 72100 Brindisi, Italy

* Corresponding author. Tel.: +39-0831-201254. E-mail address: alessandro.lipari@enea.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.2026.06.079