Tensile Behaviour of ETFE Foils with Various Types of Area Weld Seams

Abstract

ETFE foils are already an established building material in membrane construction. Many prestigious buildings have already been realised with the transparent and printable foils. The manufacturing and installation of the mostly double-curved ETFE foil structures are made possible by the weldability of the fluoropolymer. The manufactured weld seams can be divided into area and edge weld seams. Both types of ETFE weld seams provide a lower uniaxial tensile strength in comparison to the base material. Weld seams in ETFE structures are the decisive points for the limit state design, see also FprCEN/TS 19102, which for the first time provides a standardised design concept for membrane structures based on the Eurocode design philosophy. With the release of prCEN/TS 19102, a minimum tensile strength and a partial safety factor for area weld seams are given relying on the partial safety concept of the Eurocodes according to EN 1990. Nevertheless, the given values are not based on a comprehensive experimental test evaluation so far. In the frame of this contribution, for the first time, results of investigations into the tensile strength of different configurations of area weld seams are presented. These configurations include different manufacturers, foil products, foil thicknesses, test temperatures, types of area weld seams and welding processes. Based on these results, a general minimum requirement for the tensile strength of area weld seams could be determined for future standardization processes beside that a new reliability analysis according to EN 1990 for the determination of the partial safety factor for area weld seams has been carried out. These new results will be used to improve the design concept of the future Eurocode for membrane structures which will be developed on the basis of prCEN/TS 19102. In this contribution first results of this investigations are presented

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