The Testing And Research On The Working Stress Measurement Of Concrete By The Grooving Method

The measurement of working stress is to measure the actual stress in a working structure component. The actual working stress of the concrete structure is one of the important indexes which reflect structure state, and it is one of the important parameters for building alteration and strengthened. So, the measurement of the actual stress seems particularly important in concrete structure.In the stress test of structure behavior, the measurement of working stress of concrete structure is a difficult problem to be solved. Stress releasing is a effective detecting method in the measurement of working stress of concrete structure. On the basis of finite element analysis, 5 concrete columns were made to carry on the experimental study about the measurement of working stress of concrete by the grooving method, a kind of simple and convenient, practical and reliable method was expected to find out to measure the actual work stress in concrete structure. The paper mainly includes the following contents:1. The release of stress on the measurement point was analyzed by the finite element program ABAQUS while using the grooving method, inlcude cuting transverse grooves, vertical grooves and quad ring hole, and the curves of stress-depth were drawn. The results indicate that when using the grooving method to release the stress of the concrete, the results of cuting two transverse slots have the same effect as cuting four slots came into being a quad ring hole, and also agree substantial effect as the ring-hole method of document [40], the results indicate that when the solts depth was 34mm, the stress on the concrete surface can be released to zero.2. Five concrete columns were tested and the test results were compared with the results of the finite element analysis. The strain of which depth the stress was released by theoretical calculation was concerned in the experiment. The release of stress when using the grooving method during different levels load was studied, and the residual strain owing to disturbance is unrelated with the load, its numerical value is absolutefigure rather than relative number value. According to the test result of this paper, the value of residual strain owing to disturbance factor is about -39 με . The experimenterror could be controled under ±10 με when recouped the effect of disturbancefactor.3. The influence factors including temperature and water on the measurement results of working stress of concrete columns in document [40] were analyzed. The results of the grooving method and the ring-hole method were compared and their potential application in practical projects were proposed in this paper.