Behaviour of bond lines in DVW reinforced timber connections

This paper presents a study of the behaviour of bond lines of Densified Veneer Wood (DVW) reinforced timber connections. Studies by Leijten in the 90s have shown that reinforcing timber connections with DVW results in a significant enhancement of connection properties. The DVW is in these connections glued to the timber. Recently these reinforced connections were studied in column-beam and splice type arrangements using a connecting flitch plate. In these arrangements additional stresses are introduced in the bond line. For the present study the fracture mechanical properties of bond lines between DVW and Norway Spruce were determined experimentally. These properties were implemented in three dimensional finite element models to study the behaviour and capacity of the bond line of the connection. Also an experimental study is presented to verify the numerical procedure. It is concluded that the numerical predictions correspond well to the experiments. It is also concluded that the bond line of the connection does not fail if the tested epoxy and polyurethane adhesives are used with a bond line thickness between 0.2 and 0.7 millimetres.