PSI - Issue 84

Francesco La Fortezza et al. / Procedia Structural Integrity 84 (2026) 368–375

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• They define criteria for technical and safety escorts, including possible cooperation with the Traffic Police and specialized operators for transit monitoring and traffic management. • They assign clear responsibilities to bodies tasked with evaluating the compatibility of weights, dimensions and infrastructural impacts, including the use of remote monitoring or digital tracking systems.

From a technical standpoint, the LG TE operate systematically on:

• Assessing the compatibility of exceptional vehicles with road superstructures and structures using verification protocols based on load parameters, stress distribution and geometric characteristics of the network; • Establishing schemes for checking and monitoring infrastructure elements (bridges, viaducts) involved in the route, including specific structural inspections prior to authorization; • Classifying exceptional transports by mass, dimensions and type (indivisible pieces, complete convoys, etc.), with corresponding thresholds and technical evaluation procedures; • Defining operational control methods for the convoy during transit, including monitoring systems, communication with control authorities, and use of specialized escorts. Specifically, the TE Guidelines define traffic load models : a traffic load model is a conventional representation of the variable actions due to vehicular traffic that may act on a bridge and that must be considered in structural calculations to ensure the safety and serviceability of the structure. • Free traffic + normal transit speed: The most unfavorable combination of exceptional vehicles and load pattern 1 is considered; a dynamic amplification coefficient is applied as a function of the span length. • Free traffic + reduced speed: The combination of an exceptional vehicle and load pattern 1 is considered without dynamic amplification. • Stopped traffic + reduced speed (30 km/h) + no transverse restriction: Only the exceptional vehicle in the most unfavorable longitudinal position is considered. • Stopped traffic + reduced speed (30 km/h) + transverse restriction: As above, but with constraints on the transverse position of the loads. These differentiations are used to model different real operating conditions and to ensure that the structural calculation accounts for the worst possible scenarios. 3. TES Software: verification methodology developed by SINA in accordance with the LG TE The document aims to illustrate how SINA has incorporated the provisions of the LG TE by developing software that enables structural analysis of individual structures, thus allowing ASTM Group’s concessionaire to issue the necessary authorization for the transit of exceptional vehicles. Starting from finite element modelling of the structures and performing sectional checks in the most engineering-relevant areas, such as mid-span and support sections, it was possible to create a database with all the major structures for each individual concessionaire. Following the issuance of the LG TE, SINA, as the engineering company of the ASTM Group, developed software capable of processing verification requests for the transit of exceptional vehicles over the structures present along the motorway routes The LG TE define four principal traffic load conditions to be considered in the structural verification: