Mechanical performance of glued-in rod glulam beam to column moment connection: An experimental study

Engineered timber elements are gaining wide acceptance in construction with the increased practice of mass timber structures. The design of moment resistance connection is a contentious issue amongst practitioners and researchers. However, studies available on the performance of timber frame moment resisting connections made of various engineered timber sections are quite limited. This paper presents the outcome of a research study on the experimental assessment of the mechanical performance of a glued in rod (GIR) to glue laminated timber (GLT) beam to column moment connection. The research was carried in two stages: (1) investigating the pull-out behaviour of a GIR embedded in GLT and (2) verification of a full scale GLT moment connection using GIRs. The results of GIR pull-out testing revealed that the failure is mostly characterised by interface (GIR to GLT) shear bond delamination and slippage. Rod slip failure mode in the GLT was also observed in the full-scale connection tests. Subsequently, using the experimental data gathered in the two stages of testing, a simple approach to estimate the moment capacity of full-scale connection using three parameters and an analytical approach to estimate the rotational stiffness of GIR to GLT connection are presented. Furthermore, existing design formulations to predict the moment capacities of GIR to GLT are compared with the experimental data. The study enables a better understanding of the mechanical performance of a GIR to GLT moment resistance connection. Further, studies are needed with different parameters that influence the behaviour of GIR to GLT connections.