预应力钢丝绳加固后的RC简支T梁承载能力退化研究

Study on Load-bearing Capacity Degradation of RC Simple-supported T-Beams Reinforced with Prestressed Steel Strands

摘要:

预应力钢丝绳加固方法在国内桥梁加固中应用已超过10 a，但部分最早采用该方法加固的桥梁出现了承载能力不足的问题。为深入分析这一现象，通过对比两片运营10余年的预应力钢丝绳加固简支T梁的静载破坏试验，重点研究T梁跨中挠度、裂缝及应变随外荷载变化的情况。结果表明，抗弯承载能力的退化主要源于加固时所增加的刚度随着时间的推移逐渐减弱。经过进一步分析，刚度降低的主要原因是预应力钢丝绳的应力松弛。这一结论为今后预应力钢丝绳加固技术的应用与改进提供了重要的参考依据，有助于提高桥梁的长期安全性与可靠性。

Abstract:

The prestressed steel strand reinforcement method has been used in bridge reinforcement in China for over 10 years. However, some of the earliest bridges reinforced by this method have experienced issues with insufficient load-bearing capacity. To analyze this phenomenon in depth, the key research focuses on the situation of mid-span deflection, cracks and strain of T-beams with the change of external loads by comparing the static load failure tests of two prestressed steel wire rope reinforced simple-supported T-beams that have been in operation for more than 10 years. The results indicate that the degradation of anti-bending load-bearing capacity is mainly due to the fact that the increased stiffness during reinforcement gradually weakens over time. Further analysis reveals that the main reason of the stiffness reduction is the stress relaxation of the prestressed steel strands. This conclusion provides the important references for the future application and improvement of prestressed steel strand reinforcement technology, which helps to improve the long-term safety and reliability of bridges.