Influence of number of layers on embedment strength of dowel-type connections for glulam and cross-laminated timber

The purpose of this paper is to provide a better understanding of the embedment behaviour of dowel type fasteners in laminated timber. The influence of the number and thickness of the lamellas on embedment strength in glued laminated timber (GLT) and cross-laminated timber (CLT) is experimentally investigated and discussed. Full hole embedment tests in compression were conducted with specimens of equal properties (thickness, density), only with changes in the investigated parameter. The results show the embedment strength in CLT is influenced by locking effect of thinner crossed layers. In addition, the densification of crossed layers-the hardening effect-is clearly pronounced and leads to higher embedment stresses and strengths at larger dowel displacements. Stiffness values are presented in this paper but not discussed. The comparison of embedment strength values with well-known empirical models showed good agreement for GLT. In contrast, the results for CLT were far below the values calculated with existing models and are discussed in the paper. The findings are important to provide a safe and efficient joint to achieve more efficient use of CLT products.