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用梁格法建立了无黏结预应力混凝土斜交空心板梁桥的上部结构有限元模型,对比研究了3种工况的铰缝损伤对桥梁自振特性的影响。由结果分析发现,斜交空心板梁桥前五阶振型均表现出一定的空间特性,各阶振型的变化主要表现在横桥方向;自振频率均随阶次的增加,对铰缝损伤的影响敏感性增大;不同部位的铰缝损伤对自振频率的影响程度不同,跨中横向均匀损伤比四分点均匀损伤的影响程度相对较大,单铰缝损伤对结构低阶自振频率的影响不明显,但高阶频率对单缝损伤的敏感性较高。3种铰缝损伤工况下,各阶频率相对变化率与铰缝损伤程度之间均满足指数函数增长的关系。
The superstructure finite element model of the unbonded prestressed concrete skewed hollow girder bridge was established by the beam method. The influence of the joint damage of the three conditions on the natural vibration characteristics of the bridge was compared. From the result analysis, it is found that the first five modes of skewed hollow girder bridges show some spatial characteristics, and the changes of each mode are mainly in the transverse direction. The natural frequencies increase with order, The sensitivity of damage increased; different parts of the hinge joint damage on the natural frequency of different degrees of impact across the middle of the horizontal even damage than the average impact of a quarter of a relatively large degree of damage single-hinge joints on the low-order structure The effect of vibration frequency is not obvious, but high-order frequency is more sensitive to single-slit damage. Under the three kinds of joint damage conditions, the relationship between the relative rate of change of each order and the degree of damage of the hinge joint all satisfies the exponential function growth.