Level 3 Assessment of Highway Girder Deck Bridges according to the Italian Guidelines: Influence of Transverse Load Distribution

Abstract

The Italian Ministry of Infrastructure and Transportation adopted the guidelines on risk classification and management, safety assessment and monitoring of existing bridges through the Decree No. 578 dated 17 December 2020. This document must be used by all managing entities to prevent damage due to a lack of maintenance to these crucial components of the infrastructure system. The approach of the guidelines for existing bridges is developed across six levels, ranging from Level 0 to Level 5. The research work presented in this article is focused on Level 3, which pertains to preliminary assessments conducted on existing bridges. Through an automated procedure, the preliminary verification is performed by comparing bending and shear stress generated by traffic load schemes extracted from previous standards with the ones based on the current code. These loads are applied to a series of girder deck models, selected through a statistical study conducted on a database of bridges. Performance indices are derived from the comparison to evaluate the adequacy of previously designed and constructed structures by applying the load models specified in the current regulations for designing new bridges. The analysis results highlight a performance gap, which varies depending on the standard code at hand.