A multi-phase survey approach for post-tensioned prestressed concrete bridge decks

The assessment of existing structures is a crucial task upon which rely an efficient retrofit design. Bridges are ‘key elements’ of the infrastructural network, and ensuring their good serviceability is of paramount importance. In 2020, in Italy were enacted the ‘Guidelines for the classification, risk management, safety evaluation and monitoring of existing bridges’: the underlying philosophy is to deepen the analysis only on those bridges showing poor maintenance conditions. Prestressed concrete bridges with post-tensioned cables are one of the bridge typologies mostly affected by relevant structural issues and whose assessment is more complicated. In this research, a multiphase methodology is proposed, specifically to be applied to PT bridges. The method is organized in progressive levels of knowledges. The aim is to provide an answer about how to perform the safety assessment of these structures and how deep shall be the preliminary knowledge campaign to consider the PT bridge completely investigated.