基于振动法检测预应力混凝土梁有效应力的实验研究及有限元分析

在已建的预应力结构中,结构当前的应力检测一直是较难解决的问题。文中利用振动法研究无粘结预应力混凝土梁的振动特性,通过理论分析和实验研究发现,预应力改变了混凝土梁的有效刚度,从而改变了预应力混凝土梁的振动频率。因此可以通过振动频率值反推得到梁的有效应力。通过实验测试和有限元计算得到了预应力混凝土梁在不同预应力作用下的振动频率值,二者的结果吻合较好。研究表明,振动法可以用来检测无粘结预应力混凝土梁的有效应力,为结构的有效应力检测提供了一条参考途径。

FEM and experiment research on effective stress of prestressed concrete beam by vibrating method

Nowadays,current stress test of the prestressed structure has been difficult to be solved.In this study,the vibrating feature of a unbonded prestressed concrete beam was analyzed with the vibrating method.Through theoretical analysis and experimental study,it was found that the effective stiffness of a concrete beam was changed by prestressing force,and thereby the vibration frequency of the prestressed concrete beam was changed.Thus we could get the effective stress from the vibration frequency.In this paper,the vibration frequency of a prestressed concrete beam under different prestressing force was obtained respectively from experiment and calculation with finite element method,and the results of those two methods were in good agreement.It is demonstrated that vibrating method could be used to test the effective stress of a unbonded prestressed concrete beam,which provides reference to test effective stress of structures.