Long-term Mechanical Properties Of Steel-concrete Composite Beam Subjected To Corrosion And Loading

Steel-concrete composite beam is a composite structure made up of steel beam and concrete slab connected by connecting parts.It has been widely used in bridge construction in recent years due to its advantages such as high stiffness,light weight and convenient construction.In the actual use process,the concrete bridge face plate is generally damaged or cracked.The corrosive medium will intrude into the stud connector between the concrete slab and the steel beam along the bridge face plate,which will affect the connection performance between the stud and the concrete slab.When serious,it will even affect the working performance of composite beam.Based on this,the long-term performance of steel-concrete composite beam under the action of stud corrosion and load is studied.It has important engineering application value and theoretical significance to understand the performance degradation law during normal use and to reflect the stress state of the structure.In view of the current research status of steel-concrete composite beams,steel-concrete connectors and steel-concrete composite beams are selected as the research objects.The long-term mechanical properties test of the corrosion environment and the joint action of load on the components has completed the following main work:(1)Adopt the method of constant current accelerating corrosion to corrode the fasteners of connectors.A 225-day long-term test was conducted on 7 steel-concrete joints,including 2 uncorroded specimens and 5 corroded specimens.The effects of load and stud corrosion on long-term interface slip and concrete strain of connectors are analyzed.The effects of long-term load and stud corrosion on the performance of the components are studied.To explore the law of long-term performance degradation.(2)A specially designed loading device that ACTS together with corrosion and load.The composite beam bolts were corroded by constant current accelerating corrosion method.A 225-day long test was carried out on 11 steel-concrete composite beams,including 3 non-corrosive specimens,3 non-load corrosive specimens and 5corrosion-bearing specimens.The effects of load and bolt corrosion rate on long-term interface slip,deflection,concrete strain and steel beam strain of composite beams are analyzed.The effects of load and bolt corrosion rate on long-term interface slip,deflection,concrete strain and steel beam strain of composite beams are studied.The effects of long-term load and stud corrosion on stress redistribution of composite beams are analyzed.(3)Based on experimental research and theoretical analysis,the change rule of pin rust was introduced.A time-varying formula for the long-term deflection of steel-concrete composite beams under the action of stud corrosion and load is presented.The results are in good agreement with the test results,which verifies the correctness of the theoretical analysis.