PSI - Issue 84

Francesco La Fortezza et al. / Procedia Structural Integrity 84 (2026) 368–375 373 and Q k must be calculated by applying the corresponding loads to the same calculation model. The more complicated part of the software concerns the calculation of the nodal forces f j . Each load lane, whether due to the exceptional vehicle or to the usual traffic loads, must be made to slide by the software over the point cloud representing the slab, in order to find the load positions that generate the maximum external actions E i . For this reason, the software considers a finite number of paths, represented by mixed-line geometric axes; the load lanes must be shifted along these paths. For each check, depending on the area where the load must be maximized (right or left side of the structure for the beams, centre or ends for the cross-beams), the results obtained for the relevant paths are summed. 3.2. Admissible values The software is capable of completing the analysis regardless of the limit states considered for determining the maximum admissible values Q i . The new exceptional transit guideline requires that for each bridge a trafficability check be carried out according to the bridge guidelines and effectively prescribes only that the structures be verified at the Ultimate Limit State, using safety factors calculated with respect to a 5-year return period. However, in addition to imposing that the passage of an exceptional vehicle should not cause collapse of the structure, it may be appropriate to also require that the stress state caused by the transit does not lead to irreversible damage. In other words, it is recommended to carry out checks also considering the Serviceability Limit States in the frequent combination of the analysis, for example checking that the permanent cracking of the reinforced concrete parts does not increase due to the load. It should also be considered that if a vehicle is given permission to cross, it could potentially transit over the bridge many times and with significant frequency. 3.3. Software TES – Verification Methodology Developed by SINA in accordance with the TE Guidelines The web interface was developed to streamline the authorization issuance process managed by concessionaires, each of which operates within its own working environment and is responsible for specific highway sections, in relation to haulage companies submitting requests. The operator is only required to enter the vehicle characteristics and select the entry and exit points of the motorway network to be travelled; the software automatically selects the models of the engineering structures affected by the vehicle passage and provides the verification results in accordance with the prescribed administrative procedure.

Fig. 2. Input Screens of the Web Application

Once the FEM models have been generated and the associated binary files created, containing the information required to perform sectional verifications for each individual structure for the transit of a generic exceptional vehicle, it is possible to proceed to the web application module. In addition to the computational models, databases must be prepared containing information related to: motorway sections and any secondary routes; engineering structures (bridges, viaducts, culverts, underpasses, overpasses) and interchanges, each with their respective geographic coordinates and chainage (pk).