Experimental Study And Analysis Of Fatigue Behavior Of Reinforced Concrete Beams Under Marine Corrosion Environment

In the 1940s,due to the need of industrialization,urbanization and energy development,reinforced concrete members were used to the maximum extent in coastal and offshore structural engineering.In the harsh environment of seawater corrosion,alternation of wet and dry and cyclic loads for a long time,the corrosion of steel bars eventually led to serious structural damage.So fatigue failure occurs under the cyclic load of sea waves,which affects the service life of the structure.Corrosion fatigue is an important cause of durability problems,which has received high attention.At present,the research data in this field are insufficient,and the research on the development law of corrosion fatigue should be in the stage of imperfect research.In this paper,the experimental study of reinforced concrete test beams under cyclic loading in atmospheric,freshwater and chloride environments is carried out.The mechanical properties and stiffness damage evolution of reinforced concrete members under three kinds of environments and cyclic loads are further explored.At the same time,the failure mode,crack width,deflection development law and fatigue life are analyzed.1.Through data analysis,in order to further study corrosion fatigue and its basic mechanical properties of reinforced concrete members in harsh marine environment,cyclic load fatigue tests were carried out in atmospheric environment,freshwater environment and chloride salt corrosion environment.2.The effects of the interaction of corrosion,fatigue and corrosion fatigue on the bearing capacity,stiffness and deformation performance of reinforced concrete beams are further verified through experimental design and test.3.The coupling effect between corrosion and fatigue is further verified by the research.The results show that the fatigue life of reinforced concrete members is closely related to loading environment and cyclic load level,and the ductility and ultimate bearing capacity of reinforced concrete members are significantly reduced under the combined action of corrosion environment and cyclic load.Under the combined action of chloride corrosion and the upper limit of 0.7PU cyclic load,the fatigue life decreases the most.The research in this paper is of great significance to further study the durability of coastal and offshore structural engineering.4.Combining with the results of this study,the fatigue life and its regularity of reinforced concrete beams in harsh marine environment are further studied,and the S-N curve(fatigue life curve)given to the existing experimental data is given.According to the existing literature and experimental results,a fatigue life prediction model is established based on the stiffness damage accumulation of reinforced concrete beams.The error between the predicted results and the experimental results is less than 13%.