PSI - Issue 62

Eleonora Bruschi et al. / Procedia Structural Integrity 62 (2024) 299–306 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Keywords: Post-tensioned concrete bridges; Special inspections; Guidelines; Post-tensioned degradation; Test procedures

1. Introduction According to the Italian Guidelines 2020, Special Inspection for the assessment of reinforced concrete bridges and viaducts with post-tensioned cables (PT bridges) are required in order to determine where to perform investigations and how or which tests are more suitable. The proposed Italian methodology, presented in the document named “ Ispezioni speciali su ponti esistenti in c.a.p. a cavi scorrevoli ai sensi delle Linee Guida: la classificazione e la valutazione accurata ” (hereinafter referred as IGSI - Italian Guidelines for Special Inspection) has been developed drawing inspiration from the Guidelines of the Federal HighWay Administration (FHWA, 2013) and from the Highways England in CS 465 – Management of post-tensioned concrete bridges (Highways England, 2020). As shown in the flowchart of Fig. 1, Special Inspection are based on a multiphase procedure, which allows a progressive deepening knowledge of the PT system status and to optimize interventions. Phase 0 and Phase 1 are compulsory for all bridges regardless of the level of defects detected on the structure. Then, the assessment phase gets more accurate depending upon the gravity of the defects.

Fig. 1. Flowchart of the multiphase method (Mazzatura et al.).

The aim of this work is to validate the procedure suggested by the Italian Guidelines for Special Inspection (IGSI) and to provide detailed instructions on how to accurately conduct an evaluation of PT bridges/viaducts. To serve this purpose, a seven-span long bridge made up of several cable families was chosen to be proposed as a case study. 2. Case study Dora Riparia River Bridge, located in Avigliana (Turin) SP197 Provincial Road, was built in 1958. The bridge is seven-span long for a total length (from abutment to abutment) of 155.20 m and consists in a simply supported