Study On Probability Model Of Flexural Bearing Capacity Of Corroded Steel Beams In General Atmospheric Environment

Steel structures exposed to atmospheric corrosive environments for a long time are highly susceptible to rust damage,resulting in deterioration of the bearing capacity of the components,seriously affecting the subsequent service performance and reliability of the structure,and even causing safety accidents.The corrosion of steel structure i s affected by many factors such as materials and environment,and has obvious random characteristics.In this paper,the corrosion surface is statistically analyzed by probability method,and the probability model of the bending capacity of corroded steel beam is established,which is the existing corrosion steel.Structural reliability analysis provides theoretical support.The specific research carried out in the thesis includes the following aspects:(1)Through the surface topography test of the general atmospheric environment accelerated corrosion steel plate and natural exposure corrosion steel plate,the statistical law of surface characteristics and thickness loss of corroded steel was studied,and the probability model of corrosion equivalent loss thickness and non-uniform corrosion ratio was established.The rust depth random field model is used to accurately characterize and simulate the corrosion surface.(2)The monotonic tensile test of accelerated corrosion and natural exposed corrosion specimens was completed.Based on the rust statistical characteristics and stochastic model,the rusted steel map reconstruction and monotonic tension finite element parametric analysis were carried out.Based on the statistical analysis of experimental and numerical simulation results.Probability model of yield strength of corroded steel obeying normal distribution is proposed,and the degradation law of mechanical properties of corroded steel is revealed.(3)Considering the influence of corrosion thickness loss and strength degradation,the calculation formula of the flexural capacity of corroded steel beams is proposed,and the influence of different corrosion characteristics on the flexural capacity of corroded steel beams is analyzed.Finally,the equivalent loss of corroded steel is introduced.Based on the thickness probability model and the strength probability model,the probability model of the bending capacity of corroded steel beams is established.