Determination of Actual Yield and Tensile Strength of Existing Steel Structures by Testing on Small Specimens

This paper presents a new tensile testing method using small, bow-tie-shaped steel specimens, that can be extracted by drilling a M39 bolt hole with a hollow core drill. This core can be used for testing, while minimizing the impact of material extraction on the structure. Tensile tests have been carried out on these small specimens in a number of thicknesses and steel grades covering the field of existing steel structures. The testing method is validated by comparison with standardized tensile tests. The small specimen tests show equivalent results to standardized tests, while requiring far less material. By finite element modelling, the suitability of the method for different steel types is assessed within the scope of existing steel bridge structures. The method is proposed as alternative to current standardized test methods to determine the steel grade or the actual values of fy and fu.