Study On Seismic Performance Of Corroded H Steel Column Under Neutral Salt Spray Environment

In recent years,the steel structure has been widely used in practical engineering because of its high strength,light weight and excellent seismic performance.However,many steel structures in the marine atmosphere environment for a long time are difficult to prevent the occurrence of corrosion by protection measures.Corrosion not only can weaken the cross-section of the component,but also will result in many rust pit of different sizes under the surface.Rust pit will make the steel surface produces stress concentration,reduce the plasticity and fracture toughness of steel,and accelerate the initiation and propagation of the crack,which reduces the seismic performance of the steel structure.According to the above problem,from two aspects of material and components,the effects of corrosion on the steel mechanical properties and the seismic behaviors of steel frame columns are studied in this paper.The main research work include:(1)Six steel frame columns with different corrosion degree and a batch of plate specimens were obtained by spraying neutral salt spray periodically outside,and 7uncorroded steel columns were combined with the existing ones,and the results showed that the corrosion rate of steel frame columns was higher than that of non-corroded steel columns.The surface morphology characteristic parameters were obtained by scanning the surface morphology of the corroded plate specimens.The relationship between the surface characteristic parameters and the weight loss rate was established by statistics and analysis of the obtained characteristic parameters.(2)Based on the monotone tensile test of plate specimens,the influence of corrosion degree on the failure morphology and main mechanical properties of the plate was studied.The results showed that the fracture cross-section of the specimens with severe corrosion degree was irregular,and with the aggravation of corrosion,the fracture cross-section of the specimens with serious corrosion degree was irregular.The tensile constitutive model of corroded steel was established because of the obvious decrease in the performance of the specimens and the difference in the performance degradation between the flange plate and the web plate.(3)Seven corroded steel frame columns with corrosion ages of 0,4,6,8,10,12 and 14 were subjected to low cycle reciprocating loading tests.The failure pattern,hysteretic curve,skeleton curve and load-strain curve of H-beam frame column under corrosion are studied,and the degradation rule of seismic behavior of corroded H-beam frame column is obtained.(4)Based on the finite element analysis software ANSYS,the finite element model of the steel frame column is established and analyzed,and the reliability of the finite element simulation analysis is verified by comparing the results obtained by the finite element calculation with the test results,so that the weight loss rate of the component and the width-to-width ratio of the flange are carried out,The expansion and analysis of the effect of high-thickness ratio and axial compression ratio on the performance of the material.