Study On Fire Resistance Of Axial Compression Column Made Of S690 High Structural Steel

The study on the fire resistance of high-strength structural steel S690 axial column can be divided into two ways:the first one is to study the stable bearing capacity N_cr,T under high temperature by means of constant temperature loading;the second is through constant In the way of carrying the temperature rise,the steel column is placed in a fire-heating environment to study the critical temperature T_crr under the steel column fire.In this paper,the fire resistance of high-strength structural steel S690 axial column will be studied by these two methods.The existing design specifications for fire resistance are based on experimental studies and numerical studies of a large number of ordinary carbon steel components.There is no specific design method for high strength structural steel.There is no specific design method for the fire resistance of high strength structural steel.In this paper,the numerical simulation method is used to calculate the fire resistance performance of high-strength S690 structural steel axial compression column by calculating the stability bearing capacity of high-strength steel column under high temperature and the critical temperature value of high-strength steel column under fire.The result is:（1）Based on the test data of the mechanical properties of high-strength structural steel S690 under high temperature,compared with the high-temperature properties of ordinary carbon steel,the results show that the high-strength structural steel S690 is predicted by the deterioration of mechanical properties of ordinary carbon steel at high temperature is not suitable.Using the Origin software to fit the high-temperature structural test results of high-strength structural steel S690,the prediction formula of material properties（elastic modulus,yield strength and ultimate strength）degradation of high-strength structural steel S690 at high temperature was proposed.（2）The finite element analysis model of welded H-type axial compression steel column was established by using finite element software ANSYS.The reliability of the model establishment was verified by comparison with the experimental results in the existing literature.The parameters of the stability coefficient of high-strength structural steel S690 welded H-axis axial compression column under normal temperature and high temperature are analyzed,and the column curve under normal temperature and high temperature is redrawn according to the finite element calculation value（stability coefficient-long-ratio ratio relationship）.The calculation design of the stability coefficient of high-strength structural steel S690 axial compression column under normal temperature is proposed.The calculation method of high-temperature stability coefficient in Chinese,European and American codes is revised.The high-strength structural steel S690 axial compression column is proposed.The coefficient calculation design method is summarized and the design method for calculating the stability coefficient of high-strength structural steel axial compression column at high temperature is summarized.（3）The finite element software ANSYS was used to establish the steel column thermal analysis model under different working conditions,and the reliability of the thermal analysis results was verified by the standard steel column heating formula.By analyzing the thermal analysis results,the steel was fired under different working conditions.The section temperature distribution law of the column is analyzed and a simplified model for calculating the section temperature distribution is proposed.（4）Based on the results of thermal analysis,a thermal-structural coupling analysis model was established,and the same calculation model as the fire resistance test parameters of axial compression steel columns in the existing literature was established,and the reliability of the model was compared.The critical temperature analysis of the high-strength structural steel S690 axial compression column under different working conditions is carried out,and the design suggestions for the critical temperature check of high-strength structural steel S690 axial compression column under different working conditions are proposed.