钢-混凝土组合楼盖抗火性能的数值分析方法

为模拟高温下钢筋与混凝土、压型钢板与混凝土之间的粘结-滑移性能,本文分别建立了四节点粘结-滑移空间单元刚度方程和八节点粘结-滑移单元刚度方程,给出了高温下混凝土的破坏模型和非线性本构关系及结构钢在高温下的应力-应变关系和屈服模型;然后建立了用于模拟钢.混凝土组合楼盖在火灾下的结构性能的有限元格式,并编制了相应的分析程序。通过与常温下和高温下试验结果进行对比,初步验证了本文分析理论和程序的正确性和可靠性。

Numerical approach of behavior of steel-concrete composite slabs subjected to fire

In order to model the bond-slip behavior between steel reinforcing bars or steel profile deck and concrete at elevated temperature, the stiffness matrices of a 4-noded element and a 8-noded element were developed based on the concept of FEM respectively. The failure model and nonlinear constitutive relationship was proposed for concrete subjected to triaxial stresses at high temperature. The strength and stress-strain relationship was presented for structural steel at elevated temperature. Employing the Newton-Raphson iteration, a nonlinear finite element formulation was established to analyze the structural behavior of steel-concrete composite floors subjected to fire. Based on this procedure, a corresponding program was composed in Fortran Language. The effectiveness and reliability of the approach were verified by the good agreement between the theoretical results and results obtained by experiments both at room temperature and at elevated temperature.