Bearing model for glued laminated timber in bending – new aspects concerning modelling

Current product standard EN 1194 for glued laminated timber (GLT) is in
revision. Based on grown knowledge and experience with the product GLT since the first erection
of EN 1194 most characteristic values are still in discussion or are already corrected to constant
factors. Task of this paper is to present current available data sets of boards of spruce (picea Abies
karst.) tested in tension, and hence build up GLT. Emphasize has been taken on establishment of a
bearing model for GLT in bending, based on a statistical mean regression function for description
of the relationship between tension strength of boards and hence build up GLT which is conform
to EN 1194. In addition knowledge of representative statistical distribution functions in
combination with the determination of range of statistical parameters (mean, COV), sensitivity
analysis related to the laminating effect have been carried out in respect to formulated constraints.
Results are compared with researched publications concerning description of laminating effect of
GLT. Influence of the mechanical potential of finger joints on bending strength of GLT has been
theoretically examined and treated as second condition for GLT-model in bending and will be
presented in a separate paper. At the end a proposal for further regulation of GLT-bending
strength, based on the tension strength characteristics of the base material board is given.