Absolute strain detection method and dedicated strip specimen

Abstract

The invention relates to an absolute strain detection method and a dedicated strip specimen, and belongs to the field of reinforced concrete structure strain detection. The absolute strain detection method is characterized by comprising the steps of firstly pasting a strain gauge on the surface of a concrete structure along a direction to be detected; then measuring a resistance value R0 of the strain gauge by using a high-sensitivity digital bridge; cutting a strip specimen at the position of the strain gauge by using a cutting device; measuring a resistance value R1 of the strain gauge again after the strip specimen on which the strain gauge is pasted is completely separated from the surface of the concrete structure; acquiring the absolute strain [sigma] of the corresponding position direction by means of a formula [epsilon]=k*(R0-R1) / R0 and a formula [sigma]=[epsilon]*E according to a sensitivity coefficient k of the strain gauge and the resistance values R0, R1 before and after the strip specimen is cut. According to the invention, the specimen cutting difficulty is effectively reduced, weakening imposed on a main stress section of the structure by the operation of specimen cutting is reduced, and a triangular opening formed after the detection work facilitates the repair and restoration of the structure surface.

Description

Technical field: [0001] The invention relates to an absolute strain detection method and a special strip pattern, belonging to the field of strain detection of reinforced concrete structures, in particular to the detection of absolute strain along the longitudinal direction of the structure on the surface of a beam-column type reinforced concrete structure. Background technique: [0002] With the development of the city and the continuous deepening of various infrastructure constructions, a large number of reinforced concrete beam-column structures have entered the maintenance and use stage. In the inspection and evaluation of the built reinforced concrete structure, it is necessary to fully understand the actual working condition of the structure. For example, in the field of bridge structure inspection: in order to fully understand the actual working conditions of the structure, effective methods can be used to detect the appearance of the structure, the properties of stee...

AI Technical Summary

Problems solved by technology

[0006] 1. From the point of view of the stress and strain release effect of the structure, affected by the redistribution of stress and strain around the hole, the strain release effect of the opening (groove) on the surface of the structure on the area around the hole will rapidly attenuate as the strain measuring point moves away from the hole edge. However, the heterogeneous characteristics of concrete materials require that the strain measurement measures used need a sufficiently large measurement gauge length. The methods disclosed in these two patents will encounter stress-strain release effects and strain measurement gauge lengths in the process of realization. irreconcilable difficulties

[0007] 2. Judging from the strain measurement results, the area around the hole is still part of the structure after the hole is opened, and the hole (groove) can only completely release the stress and strain at the edge of the hole on the surface of the structure, while the above two patents submitted In the measured strain area of ​​the method, the degree of strain release in each position and direction around the hole will be inconsistent. Affected by the inhomogeneity of the concrete material, the size and direction of the stress-strain release in the measured area around the hole will be very chaotic, which will directly affect the absolute Strain Test Results

[0008] 3. Judging from the effect of applying the reverse recovery load, the tested concrete structure is a non-homogeneous and dense structure, and the stress and strain release degree of each part in the hole (slot) is inconsistent after the hole is opened (the constraint of the structure at the bottom of the hole It will cause inconsistencies in the release of stress and strain at different depths), and the application of reverse loads cannot well restore and reproduce the original stress and strain state around the hole. This defect will cause the method disclosed in the appealed patent to be implemented. It is difficult to restore the strain test position to the state before the stress and strain release at the same time

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