Strengthening of structural timber İ-beams with steel elements: experimental analysis and performance evaluation

Timber which is an ecologically sustainable and renewable resource, is one of the oldest construction materials used throughout history. Nowadays, timber has become a preferred choice in the modern construction sector due to its lower carbon footprint relative to alternative building components. This widespread use has also led to research aimed at enhancing the structural performance of timber. Research on the strengthening of timber beams has predominantly focused on polymer composite applications, particularly carbon fiber-reinforced polymers (CFRP). However, the effects of steel reinforcement configurations on the structural performance of timber beam have not been sufficiently investigated in the literature. In response to this gap in the existing literature, this study; I-section timber beams produced from Ardanuç spruce has been experimentally examined through of four innovative steel reinforcement configurations and their effects on the structural performance of timber beams. As a result of the experimental studies conducted, it was observed that different steel reinforcement configurations have a decisive effect on the mechanical behavior and damage mechanisms of the beams. The results demonstrated that the rod-based (RB) reinforcement provided the most comprehensive and balanced. This configuration showed the best performance among other methods, significantly increasing stiffness by approximately 138%, maximum load by 28%, and energy absorption by 45%. However detailed analyses conducted on all groups also highlight the characteristic weak point of reinforced timber beams. İn this context; the presence of discontinuous web joint has been noted as a key element that triggers structural damage and decisive in the system's attainment of its ultimate capacity. The study concludes that while discrete steel elements, particularly the rod system, offer a highly effective means of reinforcing timber beams, their performance is intrinsically linked to the quality of the base material.