The performance of a ductile moment resisting connection between a precast concrete column and a timber beam

A ductile moment resisting joint suitable for the connection of a precast concrete column to a glued laminated timber beam is described. The design, fabrication and test performance of four variants of the joint which was fabricated from structural steel components are described in detail. The design was strongly constrained by practical considerations including the requirement that it be capable of attachment to both the beam and column at the time of erection, that wide construction tolerances be accommodated at the erection stage and that its fabrication could readily be undertaken by precast concrete and structural steel fabricators without special facilities. A capacity design approach for the joint was followed, based on the current New Zealand structural steel and structural concrete codes of practice. The design of the test joints was based on a defined strength hierarchy intended to result in large inelastic deformations being localised to the structural steelwork components. These components performed well in the tests. Some of the precast column sections tested were insufficiently reinforced for shear. Although confinement reinforcement was not provided for the purpose and it was not intended that they themselves be ductile, those precast concrete column sections with adequate shear reinforcement appeared to be capable of sustaining moment through a limited number of inelastic reverse cycle rotations even without confinement reinforcement. It appears that if such a joint is to be developed further, the inelastic rotational capacity, of the concrete column itself may more reliably provide the required ductility if confinement reinforcement is provided at the hinge position.