不锈钢焊接工字形截面短柱轴压局部稳定性能试验研究

Compression tests on local buckling behavior of welded stainless steel I-section stub columns

对奥氏体型S30408和双相型S22253两种牌号的15个不锈钢焊接工字形截面短柱开展轴压局部稳定试验研究,考察截面组成板件的局部稳定性能和截面承载力,得出了试件截面的应力-应变关系曲线。研究结果表明:厚实截面的试件承载力高于其截面屈服荷载,试件截面应力-应变关系曲线表现出典型的非线性特性和应变硬化特征;而宽肢薄壁截面的组成板件发生过早的局部屈曲,使得试件承载力不能达到截面的屈服荷载,需要对截面强度进行折减。基于得出的试验结果和现有的其他试验数据,对现有设计方法,包括欧洲规范EN 1993-1-4和美国规范SEI/ASCE 8-02中的有效宽度法以及直接强度法计算得出的截面承载力进行评估,表明根据欧洲规范EN 1993-1-4和直接强度法计算得到的截面承载力偏于保守,而美国规范SEI/ASCE 8-02对宽厚比较大的截面承载力计算偏于不安全,而且计算离散性较大。

Tests on a total of 15 welded stainless steel I-section stub columns under axial compression were conducted,including austenitic grade S30408 and duplex grade S22253. The local buckling behavior and load-carrying capacity of the test specimens were studied,and the cross-sectional stress-strain curves were obtained. It is revealed that the loadcarrying capacity of test specimens with stocky sections is higher than the corresponding cross-sectional yield capacity,revealing significant nonlinear and strain hardening characteristics. Meanwhile,due to local plate buckling,the ultimate load-carrying capacity of test specimens with slender sections can not reach the cross-sectional yield capacity,with strength reduction being required. The obtained test strengths and other existing test data were used to evaluate the current design methods,including the effective width method in EN 1993-1-4 and SEI / ASCE 8-02 and the direct strength method( DSM). The load-carrying capacities from EN 1993-1-4 and DSM are generally conservative for the test specimens,while the SEI / ASCE 8-02 provisions provide overestimated strength predictions for the slender sections,revealing relatively higher scatter.