高温下钢管约束型钢混凝土柱的受力性能

火灾下无防火保护的结构构件温度会迅速上升，从而造成钢材和混凝土的强度明显下降。为了研究火灾下钢管约束型钢混凝土柱的受力性能，考虑火灾下钢管约束型钢混凝土柱的不均匀温度分布及温度对材料力学性能的影响，提出了火灾下受轴心荷载作用的钢管约束型钢混凝土柱承载力的计算方法。利用有限元软件ABAQUS对提出的计算方法进行了验证，结果吻合较好。进而采用该计算方法对影响高温下承载力的参数进行了分析，研究表明：随着构件截面尺寸的增加以及混凝土强度和钢材强度的提高，构件的承载力逐渐增加，而钢管壁厚的改变对承载力并无太大影响。利用有限元软件ABAQUS分析了荷载比、构件尺寸、钢管壁厚等因素对构件耐火极限的影响，发现耐火极限随着荷载比和钢管壁厚的增加而减小，随着构件尺寸的增加而增大。

Fire performance of circular tubed steel reinforced concrete columns

The temperature of the structural components without fire protection increases rapidly in fire, and it will result in significant? decline in the strength of steel and concrete. In order to investigate the mechanical performance of circular tubed steel reinforced concrete columns in high temperature, the effect of temperature on material properties and the asymmetry of temperature are analyzed, then the calculation method of bearing capacity of axial loading columns in fire is proposed. This method is verified by ABAQUS and good agreement is achieved. The parameters affecting the ultimate bearing capacity of columns in high temperature are studied using the method. The results show that the cross-section dimension and the strength of concrete and steel have significant effects on the ultimate bearing capacity, whilst the wall thickness of steel tube has little effect. The influences of load ratio, dimensions of specimen, and thickness of steel tube on the fire resistance are investigated by ABAQUS. It is shown that the cross-sections dimensions have significant effects on the resistance. However, with increase of load ratio and wall thickness of steel tube, the fire resistance is decreased.