Thermo-mechanical Coupling Numerical Analysis Of Prestressed Steel Column In Fire Condition

In the architectural construction,pillar is the main component of the force,has important significance to the stability of the structure.The prestressing system introduced into the columns,can improve the bearing capacity of pillar,reduce the deformation of structure and saving materials.But the steels are not resistant of fire,under conflagrations as the temperature rises,the performance of steels will be changed.Prestressed cables as prestressed member,with the increase of temperature and deformation of component itself,the cprestressing force will have considerable degree of loss.In the prestressed process,prestress value is not the bigger the better,the appropriate initial prestress will improve the bearing capacoty of steel column,however the excessive prestressed instead will cause bad influence.Therefore,optimal initial prestress value need to think a lot in the analysis.Prestressed steel columns from the structure form can be divided into outside support column and inside support column.In general,the capability of outside support columnis better than inside support column,but form the building types and exterior,inside support column also has its own peculiarity,in many ways,it’s more popular with the architects and people.Combining with prestressed steel column under the fire of the loss of prestress,through theoretical analysis and numerical calculation,analysis of the loss of prestress of prestressed steel column under fire conditions,the optimal initial prestress value and maximum bearing capacity.In this paper,from the perspective of a single component,the prestressed steel column as the research object.(1)Analysis of internal bracing prestressed steel column and external prestressed steel column two forms of the similarities and differences of structure and function.On this basis this paper introduces the design idea and method of prestressed steel colum.(2)According to the principle of heat transfer,analyzes the material strength of steel at high temperatures,there will be a certain degree of attenuation to calibrate after prestressed steel column under the condition of high temperature heat coupling analysis lays the foundation.(3)Through theoretical analysis and calculation,analyzes the two forms of prestressed steel column under the condition of fire at the loss of prestress,the optimal initial values and the bearing capacity of prestressed situation,and has carried on the contrast.(4)By the method of finite element,the prestressed steel column,a coupled thermo-mechanical simulation put forward under the condition of the whole fire,different location of the prestressed steel column temperature may present different distribution.Analyzed the lasso prestressed with the change of the fire time and temperature,and compares the theoretical calculation results show that the firecontinued with the rise of temperature with time,an increasing loss of prestress in cable.In this paper,the working condition,the pillars of load,structure size and other factors constant,the lasso under different initial prestressing values influence the change of lateral displacement of the prestressed steel column in the central,demonstrated the important role of the optimal initial prestress.