预应力张拉对32 m箱梁模型动力特性的影响

Study on the Influence of Prestressing Tension on the Dynamic Characteristics of the 32 m Span Box Girder Model

基于高速铁路32 m模型箱梁的预应力张拉试验,结合理论公式的推导,对预应力混凝土箱梁动力特性的改变进行了分析和探讨。理论分析公式表明预应力会使结构竖向频率增大,而试验结果表明预应力使得箱梁模型的竖向频率减小。在预应力张拉这一弹性过程中,预应力对结构动力特性变化的影响很小,说明预应力张拉不是引起模型箱梁动力特性改变的主要因素。

Based on the prestressing test of 32 m span box girder model used in the high speed railway, and combined with the deduction of the theoretical equation, the changes of the dynamic characteristics of prestressed concrete box girder were analyzed and discussed. The analysis of the theoretical equation displayed that prestress would lead to the increase in the vertical frequency of the structure of the box girder model, while, the test results showed the opposite. In the elastic process of the prestressing ten- sion, the prestress had insignificant influence on the changes of dynamic characteristics, which proved that prestressing tension was not the main factor contributing to the changing of dynamic characteristics of the box girder model.