基于拟夹层板法的高温及过火后网架结构计算方法研究

Calculation method based on equivalent sandwich plate method for grid structures in conditions of evaluated temperature and post fire

常温条件下,网架结构的拟夹层板法具有精度高、计算方便等特点,广泛应用于工程实际,但是高温条件下结构钢的性能蜕化,拟夹层板法的应用受到限制.将拟夹层板法位移计算离散化,提出一个适用于高温条件下的位移计算公式.以典型的正放四角锥网架结构为研究对象,考虑高温下材料热力学参数,选取材料弹塑性本构模型,采用几何非线性计算方法,通过对常温下拟夹层板法位移公式的修正,得到火灾高温下网架结构位移的简化计算方法.计算高温过火后网架结构有限元分析得到的位移值,统计有限元结果与拟夹层板法的比值,得到基于拟夹层板法的火灾后网架结构跨中位移的简化计算方法.

Due to high precision and easy calculation,equivalent sandwich plate method（ESPM）for grid structures is widely used in engineering under normal temperature conditions.As the performance of steel will degenerate under high temperature,the ESPM is no longer well applied.By making the orthogonal pyramid grid structures as research objects,considering the material thermodynamics parameters under high temperature,choosing the elastic-plastic constitutive formula,using the nonlinear solution method,and correcting the displacement formula of ESPM,a simplified calculation method for displacements of grid structures under elevated temperature is obtained.By using finite element method to calculate the displacements of grid structures after fire,and calculating the ratio of the FEM results to ESPM,a simplified calculation method based on ESPM for displacements of grid structure after fire is obtained.