Study On Static And Fatigue Behavior Of Steel-Concrete Composite Beams With Corroded Stud

Steel-concrete composite beams are widely used in industrial plants,high-rise buildings and bridge structures in recent years because of their dual advantages of both steel and concrete structures.At present,most of the structural design process only considers the security and applicability,ignoring the durability of the structure.The variable environmental erosion effects such as acid rain,chloride and sulphate,as well as the lack of construction control and post-maintenance,have caused many problems such as decreased bearing capacity,reduced stiffness and loss of service function in many structures before reaching the design reference period.Many durability problems have been discovered in the course of service,especially in the application of coastal bridges,including the corrosion of internal steel bars because of the cracking of concrete slabs,the corrosion of the steel beam and the corrosion of shear connectors caused by corrosive materials invading the interface between steel and concrete slabs,thus affecting the cooperative performance of the composite beam.Therefore,the durability study of steel-concrete composite beams is of great value and significance to China’s economic and social development.In this paper,the durability of steel-concrete composite beam is studied.The main contents include the following aspects:(1)The steel-concrete composite beam is subjected to constant current energization to accelerate corrosion,and is energized for different time to obtain different stud corrosion rates.On this basis,positive static load test and negative static load test are carried out on the specimens respectively.The mechanical properties of composite beams,such as overall bearing capacity,relative slip between materials,mid-span deflection development and strain development of steel beams,are introduced in detail after bolt corrosion.(2)The steel-concrete composite beams are modeled by ABAQUS finite element analysis software.The average diameter of the stud after corrosion is taken to simulate the corrosion rate of the stud.The deflection changes of the composite beams under positive and negative static loads after stud corrosion are analyzed and compared with the experimental values.(3)The steel-concrete composite beam is subjected to constant current energization to accelerate corrosion,and is energized for different time to obtain different stud corrosion rates.The positive fatigue test and the negative fatigue test are carried out on the specimens respectively,and the phenomena of the composite beams with different corrosion rates during the fatigue loading process were observed.The mechanical properties of steel-concrete composite beams under cyclic loading,such as fatigue life,mid-span deflection development,relative slip between materials and steel beam strain development,are also introduced.