SEISMIC STRENGTHENING OF TRADITIONAL CARPENTRY JOINTS

Traditional timber construction was based on using plain timber elements and carpentry joints that work by contact pressure and friction, often these joints had only minor reinforcement generically intended to avoid disassembling. In current practice, interventions for the upgrading of carpentry joints are mainly based on empirical knowledge according to tradition, are not specifically conceived for the case of seismic action and often result in overstrengthening. The mechanical behavior of the carpentry joints is examined with emphasis on those most used in roof structures. The main connection type is the birdsmouth joint, connecting rafters to the tie beam; its behavior has been studied numerically and experimentally in monotonic and cyclic conditions. Other forms of connection are discussed as well. Some general criteria for the seismic strengthening of these joints are presented.