高强冷弯薄壁型钢卷边槽形截面轴压构件畸变屈曲控制试验研究

Experimental study on distortional buckling control for high-strength cold-formed thin-walled steel lipped channel columns subject to axial compression

针对屈服强度550MPa高强冷弯薄壁型钢轴压构件提出了一种控制畸变屈曲的构造措施——在卷边间设缀板,并通过试验对其有效性进行了验证。试验结果表明:屈服强度550MPa高强冷弯薄壁型钢卷边槽形截面轴压构件易发生畸变屈曲,通过构造措施能有效地阻止翼缘的转动,试件的畸变屈曲荷载和极限承载力都有很大的提高;随着缀板布置间距的不同,构件承载力的提高幅度也不同;缀板间距越小,试件承载力提高越多,但当缀板间距大于畸变屈曲半波长时,缀板不能起到提高承载力的作用。最后,在此基础上提出了构件不考虑畸变屈曲影响的若干条件,供实际设计参考。

In this paper,a countermeasure to restrain the occurrence of distortional buckling of 550 MPa high-strength cold-formed thin-walled steel columns by setting batten sheets between two lips is presented,and a series of tests was carried out to investigate its validity.Results show that,distortional buckling is a common buckling mode for 550 MPa high-strength cold-formed thin-walled steel columns,the suggested countermeasure can be valid to prevent the rotation of flanges,which lets the elastic distortional buckling load and the ultimate bearing capacity of axially-compressed members increase evidently;With the intervals of batten sheets adjusted,the corresponding load-carrying capacity improvement is obviously different;Generally,the load-carrying capacity improvement is higher as the interval decreases,but when the interval exceeds the half-wave length of distortional buckling of the sections,the batten sheets may have very limited,even no effect on the ultimate bearing capacity of axially-compressed members.Finally,based on above study,some conditions that the effect of distortional buckling can be ignored were presented for giving further reference to practical design.