Evaluation of Dynamic and Fatigue Behavior of Damaged Steel Beams Strengthened with Different Types of Techniques and a New Strengthening Method Proposal

In recent years, the use of carbon fiber-reinforced polymers to strengthen fatigue-damaged steel beams has increased significantly as an alternative to traditional methods due to their easy application to the damaged area, lightweight, durability, and sustainability. In addition to all these positive contributions, there are some disadvantages, such as debonding damage under loading. These disadvantages encourage researchers to produce new materials or apply materials used for other purposes in other fields for fatigue damage. In this paper, an alternative new strengthening technique is mentioned to improve the dynamic and fatigue behavior of fatigue-damaged steel beams. This technique is a strengthening application made using epoxy-based filler and carbon fiber-reinforced polymer fabric. Numerical and experimental studies are carried out on fatigue-damaged steel beams by applying this new technique and using different carbon fiber-reinforced polymers, such as a single and double layer of fabric and a single plate layer. The most significant improvement in dynamic behavior occurred on the specimen, strengthened with this newly proposed technique. In contrast, the lowest increase occurs on the sample strengthened with a single layer of fabric. While the lowest increase arises on the sample strengthened with a single layer of fabric in terms of fatigue life, the most significant progress in fatigue behavior makes on the sample strengthened with a single plate layer. As a result of comparing the results, it is concluded that this new strengthening technique could be an essential alternative to the currently used strengthening methods.