Fire Resistance Performance Research On Combined Load-bearing Wall Of Box-type Steel Structure

The steel has the characteristics of light weight and high strength,coupled with the advantages of convenient construction and other advantages of the prefabricated building,which promoted the birth of the fabricated steel structure system.With the large-scale application of fabricated steel structure buildings,research on the fire resistance of steel structures is also very important.In the past,research mainly focused on the research of beams,columns and other components,and the research on the fire resistance of the wall is lacking.The subject study the fire resistance performance of the combined load-bearing walls based on the research project of"Study on the seismic performance of box-type steel structures"^[1].In the box-type steel structure,the combined load-bearing wall is subjected to horizontal force and vertical load,which is the main load-bearing member,so it has important practical significance for its fire-resistant design and popularization.In this paper,the finite element software ABAQUS is used to simulate the fire resistance performance of the combined load-bearing wall of box-type steel structure,and study the temperature field distribution and mechanical response under fire action.It mainly includes the key measuring points of the wall section temperature-time variation characteristics in the heating stage,failure mode,fire resistance limit,etc.The paper propose an optimization design method,the main research contents as follows:（1）Firstly,the suitable thermal parameters of the wall material are selected,and the fire resistance analysis model of the combined load-bearing wall of the box-plate assembly is established.The temperature field analysis is carried out to obtain the distribution law of the temperature field of the section and the temperature value of the key measuring points.Through the parameter analysis of the wall keel section height（rock wool thickness）,keel spacing and number of openings,gypsum board layer and thickness,cladding type,high thickness ratio,find out the main influencing factors.The temperature value of the key measuring points is selected for control,and the practical calculation formula of the predicted temperature value of the key measuring points is obtained.The design method of anti-fire optimization is proposed,which provides a reference for practical engineering.（2）Selecting the appropriate thermodynamic constitutive model of the wall material,the analysis results of the above temperature field are introduced into the stress field for thermal coupling analysis,and the main factors affecting the fire endurance are found.The paper obtains the measures of fire resistance of the box-type composite load-bearing wall under different fire-resistant structural,put forward the fire resistance design method of the wall under different fire resistance requirements,and obtain the practical calculation formula of fire endurance.（3）In this paper,the fire-resistant design method and practical calculation formula proposed for the box-mounted steel structure combined load-bearing wall provide a reference for practical engineering applications.