In the design of multi-dowel timber connections exposed to dominant in-plane moment action under varying environmental conditions, calculation of fastener forces and their directions is not well understood and difficult to perform manually. The problem is that during progressive plasticisation of the dowel group, the dowel force direction of every individual fastener joint varies significantly as loading increases. Since plastic load-carrying capacity values according to Eurocode 5 (EC5) are also direction-dependent, it becomes problematic to find the correct force angles after plasticisation of the first dowel joints. Another disadvantage of the EC5 method is that it does not consider designs of wood connections failing in a brittle manner through cracking of the wood material. This type of failure is quite common in, for example, moment loaded mechanical timber connections. The overall objective of this work is to develop a new effective and flexible finite element model to simulate progressive joint plasticisation and possible crack propagation in mechanically jointed timber structures. The model was used to simulate bending- and moisture-related deformations, elasto-plastic fastener force distribution, and crack growth in glulam beams jointed with slotted-in steel plate connections.