火灾下轴向约束钢柱性能的Shanley理论模拟

Oretical Simulation of Axial Restrained Steel Column in Fire with Shanley Model

摘要:

给出了一种运用改进的Shanley方法对轴力和弯矩共同作用下的约束钢柱的分析方法。在已有的Shanley模型上考虑轴向约束的影响，以铰链的两肢的应变作为基本未知量，并且考虑升温过程中引起的钢材的塑性变形和轴向温度膨胀，从而较为准确地得到钢柱的轴力-温度变化曲线，最后通过与初始轴力的对比得到钢柱的临界温度。并用验证过的有限元模型对分析方法进行了验证，计算结果表明分析方法吻合较好。该方法力学概念清晰，能够较为简便的对约束钢柱的抗火性能进行分析，并为约束钢柱的抗火设计提供一种简单的力学模型。

Abstract:

A modified Shanley method is proposed to study the post-buckling behavior of axially restrained steel columns under combined axial load and bending moment in a fire. The modified Shanley method considers the influence of the axial restraint, the axial temperature expansion and the plastic deformation of steel in high temperature, in which the strain of two limbs is an unknown quantity, to get the axial force-temperature relationship of the column. The critical temperature can be obtained by the contrast of the axial force-temperature relationship curve and the original axial force. The simplified calculation method is verified by an ABAQUS model. The critical temperatures predicated by the two methods agree well.The study shows that this model has the features of clear concept, fine analysis, and easy for the analysis of axial restrained column in a fire.