Study On Fatigue Properties Of Corroded Steel-Concrete Composite Beams

Steel-concrete composite structures are widely used in the field of bridge structures and building structures.The steel-concrete composite beam bridge exposed to the corrosive environment,the invasion of corrosive media caused the corrosion of studs,steel bars and steel beams,resulting in reduced load-bearing capacity,reduced stiffness,and poor ductility of the steel-concrete composite structure.These factors will directly lead to the safety performance of the steel-concrete composite structure,causing huge economic losses.The subject of this article originates from the National Natural Science Foundation of China “Research on Fatigue Performance of Steel-Concrete Composite Girder Bridges under the Action of Vehicle Loads and Environmental Factors”(Project Approval No.51678234).The steel-concrete composite beam is used as the research object and the artificial climate environment is used to accelerate The corrosion method is used to simulate the corrosion of steel-concrete composite beams under natural environment.The mechanical properties,failure forms and failure mechanism of corroded steel-concrete composite beams are studied by static test and fatigue test.The main contents include:(1)Carry out the static loading test of corroded steel-concrete composite beams,analyze the corrosion rules of studs and steel beams,and study the failure patterns of corroded steel-concrete composite beams.The law of interface relative slip distribution,flexural bearing capacity,ductility and stiffness.(2)Carry out fatigue tests on corroded steel-concrete composite beams,study the fatigue failure mechanism of composite beams,and obtain the relationship between the stiffness degradation of composite beams and the number of fatigue cycling loads,and analyze the beam fatigue life,residual deflection,and residual Changes of strain,residual slip and stiffness degradation.(3)Through the five corroded steel-concrete composite beams fatigue test data of regression analysis,established S-N fatigue life calculation formula for corroded steel beams,and the calculation formula is compared and analyzed with the calculation formula for the current fatigue life of steel beams.