预应力损伤对混凝土梁桥自振频率的影响分析

Effect of prestress loss on natural frequency of concrete beam bridges

为考察结构自振频率对混凝土梁桥中预应力变化、衰减的敏感性,建立了简支梁桥及连续刚构桥有限元模型,并计算了简支梁在不同预应力值条件下的自振频率,以及连续刚构桥预应力衰减引起的自振频率变化。结果表明,对刚度较大的混凝土梁桥,预应力变化引起的自振频率改变非常微弱,在实践中难以作为监测识别结构预应力变化、衰减的有效指标。

To study the sensitivity of the natural frequency of prestressed concrete beam bridges to the loss and change of prestress, finite element models of a simply supported beam bridge and a continuous rigid frame bridge were established to calculate the modal property variation of the structures at different prestress level. The results show that, for concrete beam bridges usually with relatively higher rigidity, the change of natural frequency caused by prestress loss is too weak to be an effective index for practical monitoring of prestress loss in concrete beams.