Numerical Simulation Research On Overall Fire-resistant Performance Of Diagonal Square Pyramid Space Trusses

Diagonal square pyramid space trusses has many advantages such as large spacestiffness, strong integrity, good seismic behavior, convenience of manufacture andinstallation, it becomes one of the most widely used structure style in space structures.However, the steel members share poor fire-resistance. Thus these structures will bedamaged or even collapse under fire. Nevertheless the study of diagonal squarepyramid space trusses centralized on its static and dynamic behavior, design methodand construction method, there are few study on overall fire-resistant performance. Sothe further research on overall fire-resistant performance of diagonal square pyramidspace trusses is very necessary.Based on existing researches, Theoretical analysis and numerical simulationhave been carried out hereby to investigate the temperature field and overallfire-resistant performance under fire conditions. The main research work covered inthis paper includes:(1) The air temperature ascending in large space building under fire issystematically analyzed. And by analyzing the influencing parameters of airtemperature empirical formula for large space building, a simplified formula isestablished, which has a high calculation accuracy.(2) A iterative method and two simplifying algorithms of calculating steelmember temperature distribution are summarized, And the simplifying algorithmsthat best fit for engineering application is determined by taking a comparativeanalysis of them.(3) The regularities of axial force and the displacement properties of the diagonalsquare pyramid space trusses without fire protection coating thickness are studiedsystematically and comprehensively, the changing processes of members, which hasthe biggest tension or the biggest compression, are also tracked, and at the same time,the regularities of support reactions were discussed.(4) The fire-resistant performance of diagonal square pyramid space trusses indifferent influence factors, including the static loading ratio, the geometric parameter and the supporting conditions, were simulated and analyzed. Meanwhile thefire-resistant behavior of diagonal square pyramid trusses is compared with otherforms of space trusses.(5) The fire-resistant performance of diagonal square pyramid space trusses inthe fire protection coating thickness were analyzed for a series of static loading ratios,based on the scheme of fire safety recommended, The fire protection coatingthickness of the structures in different influencing factors were calculated andconsolidated into form to give some advices in the fire-resistant design of diagonalsquare pyramid trusses.