Reinforced moment-resisting glulam bolted connection with coupled long steel rod with screwheads for modern timber frame structures

Currently, there is no "timber moment frame structural system," as the basic glulam beam-to-column connections (usually represented by the bolted connections with slotted-in steel plates) offer limited rotational stiffness such that they are usually treated as pin connections. This paper proposes an innovative type of moment-resisting glulam beam-to-column connection reinforced by long steel rods with screwheads (LSRSs) and long self-tapping screws (STSs). The motivation is to provide a stiff yet resilient beam-to-column connection that could possibly be used for the mid-rise timber moment frame structural system without the need of shear walls or braces. Six specimens with different diameters of LSRSs were designed and experimentally tested to explore their rotational stiffness, moment-resisting capacities, hysteretic moment-rotation responses, and the associated failure modes. Results indicated that the proposed connection could provide not only a satisfying moment resistance, but also the energy dissipation and fast repairability that is related with structural seismic resilience. The design procedures and recommendations for the proposed connection were also provided based on the tested results. The presented experimental study serves as a handy reference for future designs and applications of the proposed connection in practical engineering projects.