基于收缩徐变自辨识的大跨径梁桥长期挠度预测

Long-term Deflection Prediction of Long-span Beam Bridge Based on Shrinkage Creep Self-identification

为准确获取实际结构中的收缩与徐变时变规律,提高长期下挠预测的准确性,提出了在实体结构中直接辨识结构收缩徐变的理论与预埋式徐变自辨识系统,通过试验梁试验进行了初步验证。结果表明在采用同样的结构变形计算方法的前提下,通过徐变自辨识系统所得的试验梁徐变系数曲线可更好地代表结构的真实徐变,梁体跨中变形计算采用自辨识徐变系数的预测情况较现行规范公式预测的结果更接近实测变形。提出的预埋式混凝土徐变自辨识系统能有效识别出结构体的收缩徐变,可极大提高对混凝土结构变形预测的准确性,为大跨径梁桥的长期变形预测提供了新手段。

To accurately obtain the time-dependent regularity of shrinkage and creep in actual structure, improve prediction accuracy of long-term deflection, a theory for direct identificating shrinkage creep in structure and a set of embedded self-identification system are presented, and a preliminary validation is conducted through the experiment beam test. The results show that （1） the identified creep coefficient curve of the test beam could better represent the real creep of the structure by using the same calculation method of structural deformation; （2） the calculated mid-span deformation of the beam using a self-identification creep coefficient prediction is closer to the measured deformation than theoretical predicted result. The proposed embedded concrete creep self-identification system could effectively identify the shrinkage creep of structure, and significantly improve the accuracy of deformation prediction of concrete structure , which provides a new means for long-term deflection prediction of long-span beam bridge.