The Displacement And Internal Force Analysis Of Steel Grid Structure After Fire

In recent decades, with the acceleration of the urbanization process, the buildinghas also experienced rapid development to the super high-rise, multi-functionaldirection. Space grid structure with uniform force, stiffness, etc., has become a widelyused form of building structure. But steel yield strength and elastic modulus decreasedwith increasing temperature, when building fire occurs, the grid structure due to thedual role of high temperature and structural loads, the structure will have a largerdeformation and internal forces, therefore, analysis of the residual stress of steelstructure after a fire provide the basis for repairing work later, of great significance.At present, the mechanical properties of the steel structure in fire are mainlyconcentrated in the steel frame with smaller interior room at home and abroad,consider the overall effect of the performance analysis for a large space steel structurefire rarely involved.This article describes the analysis of domestic and foreign steel fire resistanceresearch status, elaborated thermal conductivity of steel material and steel fireprotection measures, comparative summary of national structural steel thermalproperties and mechanical properties at high temperature curve, in which introducedon the basis of fire dynamic simulation software FDS fire and finite element analysissoftware ANSYS calculation steps and analysis of ideas. Combined with a practicalproject, gives the method of use fire dynamic simulation software FDS to calculatesteel structure temperature field after fire, gives the calculation procedure of thethermal-structure coupling analysis and the method of use thermal-structure couplinganalysis to calculations residual stress and deformation of steel structure after fire,provide the basis for the formulation subsequent repair program, provide an analyticalcalculation method for similar to related research projects. This paper carried out thefollowing work:(1) Proposed the analysis technology roadmap and ideas of large space steelstructure performance after fire.(2) Through the fireproof coatings fire resistant experiments gives the equivalentheat transfer coefficient of coating, determined the heating process using the methodof arrangement thermocouple on the steel member, and contrast with the oventemperature curve, objectively reflects the insulation of fireproof coating. (3) Through investigation and gather first-hand information of the large spacesteel truss after fire, using the fire dynamic simulation software FDS reductiontemperature field when the fire broked.(4) The extracted temperature loads and structural loads common applied to thestructural mode which was established using finite element analysis software ANSYS,set the calculation parameters which are change with temperature changes, Solvingget the residual stress and residual deformation of steel grid structure after fire.