一种后张预应力筋腐蚀防护和监测的新方法

本文主要介绍一种在后张法预应力桥梁中采用的电绝缘预应力锚固体系。该锚固体系与普通的主要区别在于采用了电绝缘型的锚垫板。该垫板由圆环状承压板和塑料喇叭筒组成,而承压板中部采用传统的铸铁芯,周围包裹近乎绝缘的超高强混凝土。通过埋设电绝缘型锚垫板及采用塑料波纹管,使得预应力筋和锚具与周围混凝土绝缘隔离开来,不但能很好地起到对预应力筋的腐蚀防护,而且可应用阻抗表随时测量它们之间的阻抗。根据国外的研究成果,其阻抗值的大小反映了预应力筋受腐蚀程度。这样,可以通过监测动态阻抗值,组成无损检测系统,有效地提高预应力混凝土结构的安全性和耐久性。

A new method for corrosion protection and monitoring of post-tensioned prestressed tendons

This paper mainly introduces a kind of electrically insulated prestressed anchorage system used in post-tensioned prestressed Bridges. The main difference between this anchoring system and common anchorage system is that electrically insulated anchor plate is used. The plate consists of a circular pressure plate and a plastic horn, while the middle of the pressure plate is a traditional cast iron core surrounded by ultra-high strength concrete that is nearly insulated. By embedding the electrically insulated anchor plate and using plastic bellows, the prestressed tendons and anchors are isolated from the surrounding concrete insulation, which can not only protect the prestressed tendons well, but also measure the impedance between them at any time by using impedance meters. According to foreign research results, the impedance value reflects the degree of corrosion of prestressed tendons. In this way, the non-destructive testing system can be formed by monitoring the dynamic impedance value, and the safety and durability of prestressed concrete structures can be effectively improved.