Biaxial test procedures to determine foil properties – Background to Annex E of CEN/TS 19102

Abstract The novel European design standard for membrane structures DIN CEN/TS 19102 was published in 2024. Among others, it provides verification rules for structural foils. Particularly, it offers the possibility to base the foil design on material properties of foils under biaxial stress states. In the informative Annex E “Test procedures to determine foil properties”, biaxial test methods are provided. They include biaxial creep tests to cover long‐term loads like prestress and snow as well as biaxial hysteresis load tests to cover short‐term wind loads. Additionally, it formulates equations in order to evaluate deformation and stiffness properties. This contribution provides an overview over the possibilities which this annex offers as well as an assessment of the experimental efforts it takes. Advantages and limits of this method are explained.