Research on the Flexural Behavior of a Coastwise RS-OCT Beam That Has Endured Long-Term Fatigue Load for Years

Abstract

Retrofitted super-span old T-shaped concrete beams (RS-OCT beams) are commonly used in highway bridges in coastal cities and offshore zones in China. The realization of a practical ultimate state for this beam under a bending load is still lacking. In this study, a flexural experiment on an original RS-OCT beam subjected to a long-term vehicle cyclical load was conducted in a laboratory. Several interesting phenomena were discovered. Notably, a butt-weld joint typically exists on longitudinal reinforced bars, which may be vulnerable to bending. The RS-OCT beam simultaneously suffered from the double function of atmospheric environment and fatigue during service. Based on the time-dependent and fatigue theories of materials, finite element analysis was performed using the ABAQUS software. The flexural behavior of the RS-OCT beam at various time periods was simulated. Subsequently, the flexural bearing capacities of the beams were calculated. The safety reservation of the RS-OCT beam at various time stages was related to the change in material properties and upgrading of the loading level. The latter plays a dominant role in the service state.

Keywords

• RS-OCT beam
• coastal region
• flexural behavior
• long-term
• fatigue