Stability Behavior And Reliability Of H-shaped High Strength Steel Beam After Local Corrosion

High strength steel due to its own strength significantly increased,in the practical application of building structure can effectively reduce the components section size and weight,accordingly can also decrease the size of weld,improve welding quality and the structure fatigue life,at the same time can also reduce the all kinds of coating thickness and dosage,reduce the component production processing,transportation,installation and other expenses.Therefore,compared with ordinary steel,high strength steel is more and more widely used in large steel structure engineering due to its significant advantages in structural safety and environmental friendliness.Due to the physical and chemical characteristics of steel,it is easy to corrode when exposed to atmospheric environment,and the corrosion effect will degrade the resistance of steel structure members,reducing their reliability and safety.Around the steel structure corrosion problems in many scholars both at home and abroad research,but mostly concentrated in the uniform corrosion on the structural component performance impact category,compared with uniform corrosion and local corrosion harm the safety of the structure is more serious,so the bearing capacity of high strength steel flexural member after local corrosion influence law study is very necessary.In this paper,the bearing capacity of Q690 high-strength steel beam after local corrosion was studied by the finite element analysis software ABAQUS,and its reliability after corrosion was analyzed by combining the finite element analysis results.The main researc h contents are as follows:(1)The local corrosion damage of steel plate was simulated by the simplified morphology of cylinder corrosion pit.The existing sheet property test data of Q690 steel in our research group were used to simplify the constitutive model based on the real material property data.Considering the initial defects and residual stresses,the finite element analysis software of ABAQUS was used to establish the Q690high-strength steel beam model after local corrosion.The model is verified by comparing with the experimental results in the literature.(2)Analyze the bearing capacity of Q690 high-strength beam after local corrosion.The main parameters analyzed include: the corrosion volume loss of components,the depth of the simplified corrosion pit,the distribution location of the corrosion area,and the cross-section parameters.The influence of corrosion parameters on the bearing capacity of high-strength steel beams was obtained by analyzing the results of finite element analysis,and the bearing capacity prediction formula of high-strength steel beams with local corrosion was established under the combination of main parameters.(3)The uncertainty of resistance of Q690 high-strength steel beams after local corrosion is analyzed,and the specific statistical parameters of the uncertainty of resistance of high-strength steel beams after local corrosion are obtained through parameter statistical analysis of the material properties of members,geometric parameters and the uncertain random variables of calculation mode considering local corrosion.(4)based on the atmospheric environment of steel corrosion volume loss rate and its corrosion study the relationship between the fixed number of year,to establish a high strength steel beam attenuation model of resistance change with fixed number of year of the corrosion,a combination of high strength steel corrosion resistance statistical parameters uncertainty,JC method is used to calculate the time-varying reliability index in the design reference period,and based on the time-dependent reliability index analysis,Suggestions on the best inspection and repair time of Q690 high strength steel beam after corrosion are given,which can provide reference for the use,inspection,maintenance,reinf orcement and dismantling of the structure in the later stage of engineering.