Inspection and assessment of PT structures: results from application to an existing bridge

Pre-stressed concrete with post-tensioned (PT) cables historically represented an attractive alternative to ordinary reinforced concrete (RC). A wide portion of the worldwide existing concrete bridges was PT. As the nominal service life of those structures expires, several collapses occurred, highlighting the problem of the inspection. The main issue is that PT cables may be affected by relevant corrosion phenomena related to the presence of air or water inside the ducts: such ‘hidden’ defects need to be determined through reliable testing methodologies. This paper presents the in-progress research aiming to quantify the influence of the damage of the single cable on the entire structure. The case study is an Italian viaduct composed of simply supported beams connected by an upper slab. An extensive investigation campaign was carried out to locate and quantify the damage. Starting from the data collected on-site a series of damage conditions of cables can be simulated.