A new technique using high level prestressing to construct a rigid joint between the column and beam of timber frames is proposed in this paper. Two timber substructure specimens, two-third scale models possessing the moment-resisting connections, were tested. The connections were constructed using prestressing bars, bent flat steel bars like a U-shape bar, high-strength bars, and thick square washers. The bent flat steel bars were bonded with epoxy resin glue to both the top zones and bottom zones at the beam section with flexure to strengthen the flexural tension in the beam subjected to moment. The high-strength bars were also bonded with a beam-column joint to resist the local bearing stress due to the flexural compression zone in the beam.
The specimens were subjected to reversed cyclic loading in accordance with a prescribed displacement history. The connections tested exceeded the performance of previous other connections, in terms of stiffness, strength and energy dissipation. In particular, the stiffness of the joint functioned as well as the rigid joint of a reinforced concrete frame. A model is proposed in this paper to predict the envelop curve of the idealized moment-rotation angle relationship. Comparisons between experimental and theoretical values were found to be reasonably accurate.
