Long-term shear performance study of a reinforced concrete beam in a seasonally frozen area: a 20-year service evaluation

Purpose The purpose of this study is to investigate the current durability and shear behavior of a reinforced concrete beam that has been used for 20 years in a seasonally frozen area, evaluate its existing service performance, and propose maintenance suggestions. Design/methodology/approach The durability of the test beam, including the carbonation depth, the depth of the concrete cover, and the steel corrosion potential, was tested. The shear performances of the test beam after 20 years of service, under cracked conditions, and after steel yield were evaluated using multiple loading with finite element models. Findings While the mechanical properties of the concrete were found to remain suitable, the degree of carbonation was severe and the concrete cover was insufficient to prevent the corrosion of the reinforcement. A small amount of corrosion activity was identified in the overall structure; however, the steel bars could still fully perform their function and were unaffected by corrosion. Due to some damage incurred during the use of the test beam, its stiffness decreased. Originality/value The appearance and development of cracks and the yield of the bottom longitudinal bars were found to have a significant impact on structural stiffness, while the yield of the stirrups had a minimal impact. The partial concrete spalling and steel corrosion observed in the test beams were found to have minimal impact on the overall bearing capacity. Nevertheless, regular monitoring of steel corrosion activity in test beams should be conducted, and necessary durability maintenance measures should be taken.