火灾下铝合金梁的温度响应及影响因素分析

Temperature response and the influence factor analysis of aluminum alloy beams under fire

铝合金材料为温度敏感性材料,其用于建筑结构时,须进行必要的抗火设计。文章确定了不同边界条件下铝合金梁临界温度的判别准则,考察了火灾下铝合金梁变形及内力的温度效应,研究了跨度等因素对铝合金梁温度响应及临界温度的影响。结果表明:常温及低温阶段,铝合金梁的位移随跨度的增加而增大,随温度的继续升高,其位移基本趋于一致;铝合金梁的轴向压力随跨度的增加而减小,而轴向拉力则随之增大;载荷类型对铝合金梁内力及变形行为的影响甚微;跨度对无轴力边界梁的临界温度影响较小,而对存在轴力边界梁的临界温度影响较大;不同边界约束条件下,简支梁的临界温度最低,且规范计算所得铝合金梁的临界温度偏保守。

Aluminum alloy materials are temperature sensitive materials,so it is necessary to carry out fire resistance design for the building structure with aluminum alloy materials.The criterion for critical temperature of aluminum alloy beams under different boundary conditions is determined.The temperature effect on the deformation and internal force of aluminum alloy beams under fire is studied.The effects of factors such as span on the response and critical temperature of aluminum alloy beams are discussed.The analysis results show that the displacement of aluminum alloy beam increases with the span at room temperature and low temperature,and the displacement of aluminum alloy beam basically tends to be the same as the temperature continues to rise;the axial compressive force of aluminum alloy beam decreases with the increase of span,while the axial tensile force increases with it;the types of load have only a limited effect on the deformation and internal force of aluminum alloy beams;the influence of span on the critical temperature of aluminum alloy beams is different under different boundary constraints conditions that the critical temperature of the beam is little affected under boundary condition for which there is no axial force,and the critical temperature of the beam is affected with a greater extent under boundary condition for which there is axial force;the critical temperature of simply supported beams is the lowest under different boundary constraints conditions,and the critical temperature of aluminum alloy beams calculated according to the code is conservative.