State-of-the-art review on timber connections with glued-in steel rods

Adhesive joints have been known and applied for timber structures for decades. Hybrid joints with glued-in rods are nowadays successfully used for both constructing new and strengthening existing timber structures. Since the 1980s the research and development of timber joints with bonded-in rods have been going on, however agreement regarding design criteria for these connections has not been reached. Today, connections with glued-in rods are not included in the European design code. Thus, it is desired to gather the current state of knowledge to enable application in practice of the existing and documented knowledge and experience. This paper summarizes practical and theoretical approaches from research done regarding joints with glued-in steel rods mostly in Europe and published in English, German or Swedish. The review considers manufacturing methods, mechanisms and parameters governing the performance and strength of the joints, theoretical approaches and existing design recommendations.