Pre-failure behavior of continuous post-tensioned and post-grouted beam in case of tendon failure

Grouted tendons are a common solution for long-span bridge structures. The grout provides bond and corrosion protection for prestressing steel. However, if the grouting is defective, corrosion of the prestressing steel may initiate and eventually lead to tendon failure. The consequences and noticeability of tendon failure depend on the structure's design, with some structures experiencing more sudden failure than others. Existing methodologies allow the assessment of robustness at the cross-section level. However, tendon failure occurring on the top surface of bridge beams is often difficult to detect in practice. In hyperstatic beams, the yielding of a single cross-section is less substantial in comparison to its ability to form a plastic hinge, thereby contributing to load redistribution along the beam. In this study, four two-span hyperstatic beams with different reinforcing ratios are loaded to failure. This study assesses the member-level robustness and pre-failure behavior of PTC beams in the event of tendon failure. A non-linear calculation model has been developed to simulate the effects of tendon failure at the middle support. The model can be used to analyze the safety and robustness of post-tensioned concrete bridges with suspected tendon failure.