Current maintenance practices for aging prestressed concrete bridges are facing challenging tasks to judge structural adequacy and remaining service life even with insufficient information and invisible deterioration. For prestressed concrete bridges, remaining prestress forces and corrosion of strands are the most crucial data. To accumulate the data, full-sized and deteriorated 45-year-old prestressed concrete bridge girders were recovered from an existing bridge. The post-tensioned girders were tested to observe key performance indicators such as cracking, yielding and crushing. The proposed strain compatibility method considering average tested material properties and measured prestressing force provides reasonable estimation of the flexural capacity of the old prestressed concrete girders. From the observed flexural behavior, a flexural cracking can give a good indication of the residual prestressing force. Based on the experiment, discussion on the assessment of existing bridges and shift from safety-oriented limit states to quantitative approach for extended service life.

当前老化预应力混凝土桥梁的维护实践面临着判断结构充分性和剩余使用寿命的挑战性任务，即使信息不足和无形的恶化。对于预应力混凝土桥梁，剩余预应力和钢绞线腐蚀是最关键的数据。为了积累数据，从一座现有桥梁中恢复了全尺寸和损坏的 45 年历史的预应力混凝土桥梁。对后张梁进行测试，以观察关键性能指标，如开裂、屈服和压碎。所提出的应变相容性方法考虑了平均测试材料特性和测量的预应力，为旧预应力混凝土梁的抗弯能力提供了合理的估计。从观察到的弯曲行为，弯曲裂纹可以很好地指示残余预应力。在实验的基础上，探讨了现有桥梁的评估和从以安全为导向的极限状态转变为延长使用寿命的定量方法。