Numerical Evaluation of Failure Mechanisms and Retrofitting of Connections in Mass Timber Buildings

With the growing trend in industry towards zero carbon construction, mass timber structures are becoming more accepted globally. Beam-to-column connections in mass timber buildings are currently designed to carry shear actions. However, the connections may be considered to take moment actions and large rotations to comply with ductility and robustness requirements of the building standards. The current study deploys finite element analysis (FEA) to investigate the failure due to large deformation and rotation of a typical bolted beam-to-column connection and provides an economic retrofitting design solution using self-tapping screws (STS). The FEA is validated against current or published experimental results and is used to conduct a thorough assessment of the retrofitted connection. It is shown that a proper arrangement of screws can delay the brittle failure, develop significant moment-resisting capacity, and enhance the rotational ductility of the connection.