局部点蚀损伤下H型钢柱承载能力研究

Study of Bearing Capacity of H-Shaped Steel Column with Local Pitting Damage

为了研究局部点蚀损伤对H型钢柱承载能力的影响,建立数值模型并理论验证了其合理性。以实际结构中损伤位置为参考,分别在柱脚和柱中位置的翼缘和腹板上布置不同腐蚀程度的点蚀坑,并对各组模型进行特征值屈曲分析和非线性屈曲分析,得到其屈曲模态和极限承载能力。研究结果表明:不同分布位置、不同腐蚀程度下的H型钢柱屈曲模态并未发生明显改变,均表现为在弱轴平面的弯曲失稳;极限承载力折减系数(r)与壁厚损伤度(α)近似呈现线性关系,与点蚀损伤强度(DOP)之间的关系可用二次多项式较为准确的描述,且随着α和DOP增长,r的降低速度有逐渐加快趋势;局部点蚀范围越靠近柱中,H型钢柱承载力损失越多,故柱中为局部点蚀敏感区;用失重率(D_(w))可较好的综合考虑α和DOP对钢柱承载能力的影响,r和D_(w)在各工况下均表现出较好的近似线性关系,在实际工程中,可用失重率对局部点蚀损伤下H型钢柱进行安全性评级。

In order to study the influence of local pitting damage on the bearing capacity of H-shaped steel columns,a numerical model is established and its rationality is verified by theory. Meanwhile,the damage location in the actual structure is taken as a reference,and the pitting corrosion pits with different corrosion degrees are arranged evenly on the flange and webs in the feet and middle of the steel column,respectively. Then,the buckling mode and ultimate bearing capacity are evaluated by the eigenvalue buckling analysis and non-linear buckling analysis of each group model. The results show that the buckling modes of steel columns with different corrosion pits and corrosion degrees have not changed and are bent in the weak axis plane. The reduction coefficient(r)of ultimate bearing capacity is approximately linear with the depth of corrosive pitting(α),and the relationship between r and the degree of corrosive pitting(DOP)can be accurately described by a quadratic polynomial. The closer the local pitting range is to the middle of the column,the more the bearing capacity of the Hshaped steel column is lost,so the local pitting sensitive location is in the middle of the column. The effect of α and DOP on the bearing capacity of the H-shaped steel column can be comprehensively considered by using the weightlessness rate(D_(w)). And the r and D_(w)show a good approximate linear relationship under various working conditions. In practical engineering,the D_(w)can also be used to evaluate the safety of H-shaped steel columns under local pitting damage.