体外索加固T型刚构桥的静动力性能研究

T型刚构桥的大部分病害均与预应力损失过大有关,因此目前对T型刚构旧桥加固的方法主要是通过增加预应力索及粘贴钢板等来补偿混凝土的预应力。为评价采用这种方法加固桥梁的效果,采用空间有限元法分析了一座体外索加固后的T型刚构桥的静动力性能,并进行了试验研究。结果表明:采用体外预应力成品索进行加固,预应力混凝土T型刚构的强度、刚度、抗剪能力和承载力都有明显的提高,达到了设计的要求,但是预应力混凝土T型刚构的部分振动频率与体外索的主振频率较为接近,应采取减振措施,预防体外索的疲劳破坏。

Study of static and dynamic behavior of T-shape rigid frame bridge reinforced by prestressed external tendon

According to the fact that most defects of this type of bridge are related to loss of prestress,the main method to reinforce old T-frame bridges is to compensate loss of prestress by increasing prestressed tendons. In order to evaluate the effect of this method, the static and dynamic behavior of a T-frame bridge reinforced by prestressed external tendons was analysed by 3D finite element method, and the field test study was also made. The results show that the strength,rigidity,shear resistance and bearing capacity of old bridge have been greatly improved, but partial vibration frequencies of T-frame bridge are close to master frequency of external tendons, so shock absorbing measures should be taken to prevent external tendons from fatigue failure.