Damage Prognosis Of Steel Structure With Corrosion Into Consideration

Steel structures have the advantages of lightweight,high strength,good plasticity and other characteristics.Steel structure is a common form of architectural structure.With the increase of steel production and the increasingly mature of design,the steel structure engineering is increasing year by year and has been widely used in many civil engineering fields,such as housing,industrial plants,bridges.However,the corrosion of the steel is inevitable.Under the influence of long-term corrosion,the bearing capacity of the steel structure will be greatly reduced and the service life will become short.Therefore,it is very significant to study the prognosis of steel structures with corrosion based on historical data and the current information.The main works and achievements are as follows:(1)This thesis studies the coating of corrosion prediction model and improves the grey model(1,1)to propose an improved metabolic GM(1,1)model that can enhance the precision of forecasting the life of coating.The improved metabolic GM(1,1)is used to forecast a real concrete-filled steel tubular arch bridge with coating corrosion,and a comparison is made between the proposed model and the related reference.The result shows that the effect of corrosion can't be ignored and the proposed method has excellent precision and feasibility.(2)This thesis studies the performance of corrosion steel members and focuses on the impact of section area,bearing capacity and constitutive relation of an axial compressed steel member and H-shaped steel beam with corrosion.The result shows that elastic modulus,yield strength of the steel and the section area,bearing capacity of the steel structural members will gradually decrease with the increasing of corrosion time.Through this study,it is recommended that design value of axial compressed steel members and H-shaped steel beams with corrosion should set aside sufficient safety reserves.(3)According to the test data of corrosion steel and research findings,this thesis proposes a constitutive relation model of corroded steel.On this basis,this thesis proposes a method by integrating the Monte Carlo method and Weibull model that can forecast the damage of axial compressed steel members,H-shaped steel beams and steel structures with corrosion.Notably,the cross-section loss of members and the reduction of steel mechanical property should be taken into accounted in the building process of finite element model for sake of the effect of corrosion.The result shows that proposed approach can quickly and effectively forecast the further structural reliability with corrosion into consideration,furthermore ensure the safety of structures in the future.