混凝土轨枕预应力筋张拉过程中墩头断裂原因分析

An Analysis of the Causes for the Fracture of Pier Heads in the Course of Stretching the Pre-Stressed Reinforcement of Concrete Sleepers

在预应力筋张拉过程中,有时在墩头部位会出现断裂现象,对于预应力筋张拉工作造成很大困扰,造成这种断裂的因素有很多。利用有限元软件Abaqus对混凝土轨枕预应力筋张拉过程进行了模拟,考虑了短钢丝、锚固板磨损等因素对张拉过程中墩头与钢丝端部应力的影响,对影响墩头断裂的因素进行分析,得出以下结论:当短钢丝长度偏差10 mm时,钢丝端部的纵向应力较正常状态增大3.02%,超过钢丝极限应力达4.46%。建议在预应力钢筋张拉过程中,钢丝长度偏差控制在10 mm以内,并尽量避免短钢丝的出现。

In the process of stretching the pre-stressed reinforcing bars,sometimes the pier head may crack or be broken,which causes great trouble to the work of pre-stressing.The fracture may result from many factors such as the existence of short steel wires,the wear of the anchor plate and so on.With the help of the finite element software Abaqus,the tensioning process of pre-stressed tendons for concrete sleepers is simulated,with the influence of short steel wires,the wear of the anchor plate and other factors on the stress of pier heads and steel wire end during the tensioning process taken into account,so as to analyze the factors affecting the fracture of pier heads, upon the basis of which it is concluded that, when the length deviation of the short wire is 10 mm, the longitudinal stress at the end of the wire is 3.02% higher than the normal state, and the stress exceeds the limit of the wire limit by 4.46%. It is recommended that the length deviation of the wire be limited to 10 mm during the stretching process of the pre-stressed reinforcing bar, and the appearance of the short wire should be avoided.