Numerical analyses for the prediction of the splitting strength of beams loaded perpendicular-to-grain by dowel-type connections

The paper presents a parametric numerical study on the splitting strength of timber beams loaded perpendicular-to-grain by dowel-type connections. The main aims of the numerical investigations are: (1) find out the influence of main connection parameters on the splitting strength of beams; (2) compare the above evaluated influences with the ones proposed by the first author in a recently developed semi-empirical prediction formula. The first part of the paper presents the mentioned new semi-empirical prediction formula which has been developed by means of a survey on experimental data from literature. The formula is presented in its main aspects and later its prediction capability is discussed and compared with the ones of formulae embodied in new European and German design codes for timber structures. The second part of the paper reports the main results of parametric numerical analyses carried out in the framework of Linear Elastic Fracture Mechanics (LEFM) by means of a crack propagation approach. The analyses are performed on beams of different size loaded at mid-span by both single and multiple dowel connections. The main investigated parameters are the connection width (l r), the connection depth (h m), and the number of rows of fasteners (n). They are analysed for different beam heights (h) and for different distances of the most distant row of fasteners from beam loaded edge (h e). The numerical results are compared with available experimental test data and with the relationships embodied in the above-mentioned semi-empirical prediction formula.