The search for an adhesive to grant glulam ductile behaviour

Ductility could enhance the load-bearing performance of glulam beams. The authors propose that a ductile glulam beam could be attained by adjusting the characteristics of the adhesive layers to permit the plastic “yielding” of the interface at a certain shear level. Calculation models were developed to predict the necessary properties of the adhesive layer. The results were presented to a partner from the chemical industry. Different adhesive layers were developed and tested with small beech specimens in tensile shear loading. The most promising mixes were selected to manufacture some small glulam beams which were tested in bending. The feasibility study was a success: the beams exhibited clear signs of ductile behaviour.