| The durability problem of concrete and prestressed concrete structures caused by corrosive effects of various media in the environment has become a hot topic in engineering and academic circles.However,the research results on the deterioration of prestressed concrete performance under various corrosive media in typical industrial environment are still insufficient.In view of the reinforced concrete and prestressed concrete structures in the corrosive industrial environment such as pickling workshop,the following research was carried out according to the ideas and methods of "material mechanism,component performance and engineering application" :(1)Combined with acidic industrial environment of the corrosive medium,the corrosion mechanism of prestressed concrete was clarified,and on this basis,time-varying models of prestressed concrete material with engineering practicability was explored.An original model of concrete strength degradation described with p H was established,and an equivalent constitutive model considering the stress corrosion of the steel strand was put forward.(2)Based on the stochastic process theory of component resistance and the corrosion degradation model of materials,the modeling method of prestressed concrete beams considering bond slip and stress corrosion was proposed,and the time-varying performance analysis of corroded members with bearing capacity was carried out using the statistical theory and the Monte-Carlo method.Compared with the existing test results,the relative errors of yield moment and ultimate moment were both below 10%,which verified the accuracy of the material deterioration model.At the same time,according to the simulation results,it is concluded that the corrosion of reinforcement in the elastic stage has little influence on the mechanical properties,but has great influence on the stiffness and bearing capacity of the beam after cracking.(3)Taking the concrete structure workshop under the environment of industrial acid corrosion as the research object,the numerical simulation method was used to conduct the random process analysis of the load effect and resistance of major components,in order to explore the deterioration process of the carrying capacity and normal service performance of the building structure in the actual industrial environment.Based on the reliability theory,the time-varying failure probability of major structural components under the combined action of environmental corrosion and load was calculated and summarized.The results show that the concentration of environmental corrosive media has a significant effect on the durability and safety of key components,and the crane beam is more sensitive to the change of the concentration of corrosive media.(4)Combined with the actual industrial building structures,the theoretical framework and process of the current concrete structure life were introduced.Based on the elastic analysis method,the failure mode of the structural system was determined,and the probability combination method was used to calculate the failure probability and reliability index.The results show that: With the increase of the acid fog concentration,the service life of the scaffold column and crane beam is shortened significantly,and the service life of the crane beam is more affected by the acid fog concentration.At the same time,the parameter sensitivity analysis of the building structure under the industrial corrosion environment was carried out,the influence of different factors on the service life of the structure was discussed,and the prestressed concrete life promotion method was preliminarily explored. |
