基于内嵌式自感知钢绞线的预应力混凝土梁长期预应力损失监测

Monitoring Long⁃term Prestress Loss Caused by Prestressed Concrete Girder Based on Embedded Self⁃sensing Steel Strand

针对预应力混凝土结构长期预应力损失无有效监测技术的状况,在分析应力损失原理的基础上,提出了基于内嵌式自感知钢绞线的预应力损失监测方法,得到了预应力混凝土试验梁收缩徐变引起的应力损失,并通过规范计算得到钢筋松弛引起的应力损失,两者相加即为预应力结构长期预应力损失。监测结果表明,该方法可以正确反映预应力混凝土收缩徐变的长期预应力损失变化规律,长期预应力损失率及误差均在合理范围内,并引入了修正系数计算混凝土收缩徐变,理论计算值更接近实际值。内嵌式自感知钢绞线的拉伸试验效果和碱性浆体模拟试验效果均良好,可以将其应用到实际工程中。

In view of the situation that there is no effective monitoring technology for the long-term prestress loss of prestressed concrete structure,based on the analysis of the principle of stress loss,a prestress loss monitoring method of embedded self-sensing steel strand was proposed.Based on this method,the stress loss caused by shrinkage and creep of prestressed concrete test girder was monitored,the stress loss caused by reinforcement relaxation was calculated by the code,and the sum of the two is the long-term prestress loss of prestressed structure.The monitoring results show that this method can correctly reflect the change law of long-term prestress loss of prestressed concrete shrinkage and creep,and the long-term prestress loss rate and error are within a reasonable range.The correction coefficient is introduced to calculate concrete shrinkage and creep,and the theoretical calculation value is closer to the actual value.The tensile test results and alkaline slurry simulation test results of embedded self-sensing steel strand are good,which can be applied to practical engineering.