Dynamic behavior investigation of reinforced concrete bridge under multi-hazard effect of rockfall impact and material corrosion

Abstract

Rockfall disasters pose a significant threat in mountainous areas, leading to severe damage and potential collapse of transportation infrastructure. On the other hand, the concrete and steel materials used in these structures deteriorate over time due to environmental corrosion. Therefore, this paper aims to comprehensively investigate the dynamic behavior of the bridge pier of a simply supported reinforced concrete (RC) bridge under the multi-hazard effect of rockfall impact and material corrosion. To achieve this, a comprehensive framework is proposed for analyzing the impact force and dynamic displacements of the bridge pier, which incorporates carbonation-induced corrosion models of concrete and steel, the bond-slip model, and the contact collision model for rockfall impact analysis. The study then explores the influences of various factors, including carbonation degree, rockfall weight, impact velocity, and impact angle, on the maximum impact force and dynamic displacements experienced by the bridge pier. Experimental data from a simply supported RC beam subjected to drop hammer impacts were employed to validate the correctness of the numerical modeling method. Subsequently, the numerical model of a two-span simply supported bridge was established to comprehensively investigate the dynamic behavior of the bridge pier under the combined effects of rockfall impact and material corrosion. The findings reveal that the impact force peak does not exhibit a clear relationship with the carbonation degree, but the displacement peak increases with the carbonation degree when the material corrodes over 60 years. Furthermore, the rockfall impact force peak and the displacement peak show a nonlinear increase in impact velocities, rockfall weight, and impact angle. The outcome of this study holds important implications for the design of resilient bridges and the development of effective maintenance strategies for a multitude of bridges exposed to rockfall hazards.