Failure Projection of Corroding Bridge Post-Tensioning Tendons Considering Influential Factors and Issues

Post-tensioning has evolved to become an important technology for affecting integrity of bridge structures. However, tendon failures resulting from wire/strand corrosion have been reported within two years of construction. In response to this, a recent study introduced and evaluated an analytical modeling approach that projects initial occurrence and subsequent progression rate of wire and strand fractures and tendon failures, given statistics that characterize wire corrosion rate. The present study builds upon this model by considering and incorporating, first, fractures/failures arising not only from corrosion related cross section loss but also from resultant tensile overload of remaining wires and strands that may or may not have experienced some corrosion, and second, the number of strands per tendon, given that this parameter can vary from one structure to the next and, perhaps, within a given structure. Also performed was a sensitivity analysis that characterizes variability for different model runs, and results from this are discussed within the context of structures where corrosion damage is locally concentrated, as has been reported. The significance of each of these factors is discussed, and results are related to the timing of tendon failures on post-tensioned bridge structures.