Wide width tensile strength test is widely used to evaluate the stress-strain relationships of geotextiles and to determine the adequate geotextile type during design stage. This test provides useful data about the average strain distribution, however, localized strains due to production defects, seams and punctured zones may affect the mechanical performance of geosynthetic materials and skew test results. Furthermore, the grip type (i.e., hydraulic or roller grip) used in a tensile strength test may influence the measured stresses and strains due to clamping effect. In this study, a number of both punctured and non-punctured geosynthetic specimens were tested to determine strain distributions under wide-with tensile loading using optical flow techniques. Specimens were tested using both roller and pneumatic grips to identify the effects of clamping. A total of 7 optical flow techniques have been utilized to define strain distributions of the geosynthetics samples under tensile loading. The results indicated that optical flow techniques are highly effective in determining the average strain values. Furthermore, the image-based strains could clearly identify the performance of different grip types. No discernible change in strength was observed under the presence of punctures; however, significant localized strains were evident around the punctured area.
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