Study On Damage Assessment And Reinforcement Method Of Reinforced Concrete Frame Structure Factory Building After Fire

In China,there are 30,000 construction fires per year.Since various buildings are carriers of different values,the losses they cause are relatively large,and the economic loss is not less than one billion yuan.The structure widely used in China is concrete structure.When a fire occurs,the performance of various materials constituting the concrete structure will be affected to varying degrees,which will not only cause the disappearance of its usage function,but also cause a decrease in safety and bearing capacity.It may even cause the collapse of the entire structure,so the concrete structure needs to be reinforced.Fire temperature,damage of the components,and the reliability of the structure should be evaluated in advance,and on the basis of the evaluation,a feasible reinforcement scheme can be finally worked out.The research of this subject is based on the premise that a fluororesin concrete frame workshop of a company is required to be reinforced after fire,and a series of work has been carried out.The main contents are as follows:(1)Introduced the research background and significance of the research,from the heating and temperature fields,the mechanical properties of reinforced concrete materials under high temperature and after high temperature,the mechanical properties of structures and components under after high temperature and high temperature,and the reinforced concrete structure after fire.The research status of domestic and foreign research is discussed in the aspects of detection and evaluation,and the object to be researched and technical route of this paper are proposed.(2)The temperature judgment content is discussed from three aspects: fire duration,burn characteristics of the residue at the fire site,and appearance characteristics of the concrete structure after the fire.The temperature range and area under fire the fire scene is analyzed according to the engineering example.The most severe damage area,the severely affected area,the less affected area and the area not directly affected by the fire were determined,and the on-site fire temperature is finally determined.(3)The concrete structure detection method after fire is discussed from the aspects of concrete strength detection,steel bar mechanical property test,burned component burn depth test,concrete component deformation measurement,damaged component performance test,etc.,The identification methods of concrete structural members after fire is studied by preliminary identification and detailed identification.Through engineering examples,the appropriate methods are applied to measure the strength,mechanical properties of the steel bars,depth of burns,deformation,and component properties,and finally the results of the components are obtained.(4)Discussed the principle of reinforced concrete structure,introduced common reinforcement methods of concrete structure: spray repair method,cement grouting method,chemical grouting method,external bonded steel reinforcement method,modified force system reinforcement method,prestressed reinforcement method,outer steel reinforcement method and increase section method,through reinforcement,as well as the separate calculation and design of the reinforcement of the beam-slab column based on engineering example,the safety and usability of the structure is basically ensured,reference for reinforcement under similar circumstance is also provided.The loss caused by fire is huge.For the concrete frame structure with high proportion of application,the residual strength of the building can be more economically brought into play through on-site detection and rating after fire and reasonable reinforcement measures.Based on the previous theory and the actual fire situation of industrial concrete structure frame,this paper carries out the assessment of Engineering damage.The concrete measures of reinforcement are put forward,and the following conclusions are drawn: the temperature of the fire site can be determined by the duration of the fire,the residue of the fire site and the appearance of the fire components.Through the appraisal process of concrete frame workshop,we can get a clear understanding of the distribution of temperature field of fire components,and pay attention to the depth of carbonization,burn depth,compressive strength of concrete,mechanical properties of steel bars and deformation of components.While selecting typical fire components scientifically,we should also ensure the rationality of detection methods,so as to ensure the accuracy of performance determination of components.Sex.According to different damage grades,alternative reinforcement and repair schemes are provided.Combined with the actual project,external steel-bonded reinforcement method is adopted for columns and girders respectively,and economic and efficient reinforcement schemes are put forward.