Strengthening of timber structures with glued-in rods

• Glued-in rods (GiR) connections/reinforcement to be regarded as systems.
• System parts: timber, rod, adhesive, geometry, setting procedure, quality control.
• Ductile failure modes in GiR to be preferred.
• Few technical approvals for specific products available.
• Limited number of design rules in actual and former design codes available.

The research and development of connecting and strengthening timber structural elements with glued-in rods (GiR) has been ongoing since the 1980s. Despite many successful applications in practice, agreement regarding design criteria has not been reached. This state-of-the-art review summarises results from both research and practical applications regarding connections and reinforcement with GiR. The review considers manufacturing methods, mechanisms and parameters governing the performance and strength of GiR, theoretical approaches to estimate their load-bearing capacity and existing design recommendations.