Glued laminated timber in bending: new aspects concerning modelling

The current product standard EN 1194 for glued laminated timber (GLT) is under revision. Most characteristic values are still in discussion or have already been corrected to constant factors based on the knowledge and experience gained concerning the product GLT since EN 1194 was first established. The task of this paper is to present currently available data sets for spruce boards (Picea abies Karst.) tested in tension, and hence in constructed GLT. Emphasis was placed on the establishment of a bearing model for GLT in bending based on a statistical mean regression function for description of the relationship between the tensile strength of boards and hence in constructed GLT, which conforms to EN 1194. In addition to the knowledge of representative statistical distribution functions in combination with the determination of a range of statistical parameters (mean, COV), sensitivity analyses related to the laminating effect were carried out in respect of formulated constraints. The results were compared with researched publications. The influence of the mechanical potential of finger joints on the bending strength of GLT was theoretically examined and treated as a second condition for the GLT-model in bending, but the research work has not yet been concluded here and will be presented in a separate paper. Finally, a proposal for further regulation of GLT-bending strength based on the tensile strength characteristics of the base material board is given.