电测法应用于混凝土结构的表面应变测试

Testing Study on Concrete Surface Strain Using Electrical-resistance Strain-measurement Method

以不同标距和不同贴片时间的应变片测量预应力混凝土梁表面应变,与标距500 mm的机械表测量结果进行比较。结果表明:应变片的标距越大,测量准确度越高,通常100 mm标距的应变片测量不确定度达9%,当标距增加到300 mm时,测量不确定度下降到5%。建议在应用电测法测量混凝土结构表面应变之前,应进行同工艺条件下的应变进行标定;采用环氧黏结贴剂应变片时,黏贴应对黏贴层厚度进行严格控制,并能保证环氧黏结贴剂的充分固化条件。在无法采用规范做法对黏贴后的应变片进行固化和稳定化处理的条件下,建议尽量在短时间内使用上述条件下的应变片测量方法。该研究特别适合一般条件下,混凝土表面应变测量的研究和教学工作。

By using strain foils of different gauge and different time measuring surface strain on prestressed concrete beam and comparing the results with those of mechanical table of 500 mm gauge,the appropriate conclusions are as follows： The greater the strain gauge distance,the higher the measurement accuracy（Usually 100 mm gauge of strain gauge measurement uncertainty is 9% while that of 300 mm reach 5%）.Before the application of electrical method for measuring the surface strain of the concrete structure,the strain foils should be calibrated under the same conditions.Epoxy adhesive patches strain films,the thickness of paste should paste the strict control and to ensure sufficient curing epoxy adhesive patch conditions.In the application of epoxy adhesive to strain gauges,the thickness of paste should be under control and curing epoxy adhesive patch conditions be ensured.It is recommended to apply strain gauges in a short time without prescriptive conditions of curing and stabilization treatment.The study for the general conditions is especially suitable for the research and teaching of concrete surface strain.