Calibration of the X-ray Diffraction Technique in Measuring In-service Stresses in Corrugated Steel Bars

The X-ray diffraction technique for determining residual stresses in construction steels has been commonly used in the international scientific community for decades. Taking advantage of the concepts on which the technique is based, the authors have previously calibrated and used the technique for the in situ determination of the stress states of metallic structures in service. This article presents an advance in the latter utility by means of the laboratory calibration of the X-ray diffraction technique in corrugated steel. The interaction between radiation and steel is complex, so, in the scientific community, it is considered pertinent to resort to empirical and experimental calibration processes. Two bars of corrugated steel were subjected to increasing tensile loads. The load states introduced in the testing machine were compared with those determined by X-ray diffraction. The correlation between the values of the loads applied and those determined by the proposed technique is excellent. The experimental conditions of the calibration tests are precisely detailed so that they are easily reproducible. This work represents a necessary first step in employing the technique in the buildings or civil works.