New procedure for bridge analysis of heavy vehicles transit (NTEO)

Infrastructures such as Bridges and Viaducts can be significantly affected by the effects of Heavy Vehicles (H.V.) transit, which represent an unexpected overload, potentially greater than design stand- ard loads. Moreover, Heavy Vehicle transit authorization is a very onerous activity; as a matter of fact, safety check valuations of all the involved structures are required in reasonable time. NTEO (“New T.E. Online”) is a new H.V. transit authorization procedure, which aims to provide a semi- automatic method for estimating the assessment of several existing structures in the process of H.V. transit. The methodology is focused on the general approach of influence lines, related to the most critical sections of the examined structures (e.g. bending moment in the beam mid-span or shear in the beam support). The traditional definition of influence lines in bridge design is based on the common criteria of transversal distribution of the actions (Courbon, Massonet). Contrastingly, the NTEO procedure uses influence lines extrapolated from an explicit F.E.M. model of each structure involved in the H.V. transit. This choice requires the implementation of many calculation models, but at the same time leads to much more accurate and reliable results than the simplified theories of transversal distribution, especially when these theories can’t be applied. Once models have been created, it is possible to reuse the influence lines for different load scenarios, facili- tating authorizations for the following Heavy Vehicle transits