Strengthening Shear-Damaged Reinforced Concrete Beams Using Iron-Based Shape Memory Alloys

Advanced steel reinforcement technologies are key to enabling more durable and resilient concrete infrastructure in the face of rapidly growing demands, accelerating climate change, and extreme hazards. However, solutions for improving the performance of concrete elements in shear have historically relied on passive means where the reinforcement is only engaged after diagonal or transverse concrete cracking has occurred. This paper presents a numerical investigation on the use of prestressed iron-based shape memory alloys (Fe-SMA) to strengthen shear-damaged reinforced concrete (RC) members. Firstly, a numerical model based on test data from the literature involving large-scale shear-critical RC beams is developed using the program VecTor2. Aparametric analysis is then conducted to determine the effects of externally bonded prestressed Fe-SMA on the shear response by varying the Fe-SMA and steel transverse reinforcement volume, the level of prestressing and the bidirectionality of SMA. The main focus of the analysis is on ultimate capacity and crack closing. The results of this study indicate that RC beams retrofitted using Fe-SMA exhibit reduced shear cracking and increased shear capacities.