Fire tests on finger-jointed timber boards

This testing report summarises the experimental investigations on finger-jointed timber speci- mens, glued with different types of adhesives, loaded in tension and exposed to standard ISO-fire. The tests were performed as part of the project entitled “Fire safety of bonded structural timber elements” in the frame of a CTI-project (Commission for Technology and Innovation). The extensive testing programme on finger-jointed timber specimens was performed in cooperation with industry partners at the Swiss Federal Institute of Technology Zurich (ETH Zurich). The main aim of this research project is to clarify if the currently used design model for the fire re- sistance of bonded structural timber elements, such as glued-laminated timber, should consider the behaviour of adhesives at elevated temperatures. In this experimental study, different adhesives available on the market from adhesive man- ufacturer from Europe (such as Casco AG, Dynea AG, Jowat AG, Türmerleim AG, Purbond AG) were tested. Adhesives being used for structural applications as well as adhesives not certified according to current European testing standards for the use in structural applications were tested. The fire performance of 12 different adhesives - of type 1C PUR, MUF, PRF, EPI, PVAc, UF - were tested in a finger-jointed connection for cross-sections with a width of 80, 140 and 200 mm. In total, 49 fire tests were performed under ISO-fire exposure at the Swiss Federal Labora- tories for Materials Testing and Research (EMPA) in Duebendorf/ Switzerland. Two tests were conducted with specimens equipped with thermocouples to determine the temperature distribu- tion along the cross-section width. In the other tests, different parameters and their influence on the fire resistance were varied, such as the adhesive in the finger joint, the width of the specimen, the load level and the type of fire exposure on the testing lamella. The tests were performed in two test series in March and April, 2011 as well as in July and August, 2012. The second test ...