冷弯厚壁型钢考虑冷弯效应的屈服强度计算方法研究

Modification method for yield strength of cold-formed thick-walled steel sections considering cold-forming effect

为研究冷弯效应对壁厚6.0 mm以上的冷弯厚壁型钢屈服强度的影响,对4种不同截面、不同厚度的冷弯厚壁型钢进行了截面不同部位的材性试验研究,同时对现有国内冷弯厚壁型钢的材性试验和短柱试验数据进行了汇总。在简要回顾国内外冷弯厚壁型钢考虑冷弯效应的屈服强度计算公式及其理论依据的基础上,将各国规范计算值与试验值进行了对比。结果表明:冷弯效应对冷弯厚壁型钢的屈服强度影响较大,其影响程度与板件的宽厚比关系明显;我国规范、北美、澳洲/新西兰规范公式,以及朱爱珠基于我国规范提出的修正公式计算结果偏于保守,而欧洲规范的计算结果略偏大;我国GB 50018—2002《冷弯薄壁型钢结构技术规范》中计算方法理论依据充分,且在计算结果偏于安全的同时变异系数较小,更适合于工程应用。

In order to investigate the cold-forming effect on the yield strength of cold-formed thick-walled steel sections over 6. 0 mm thick,four cold-formed steel rectangular hollow sections with representative size and thickness were selected to investigate the material properties of different parts of the sections. Meanwhile,existing data of material property tests and short column tests were collected. The modifying formula for yield strength considering cold-forming effect based on different codes in the world were summarized,and the calculation results from those formulas were compared with the test results. It is shown that cold-forming has a strong influence on the yield strength of cold-formed thick-walled steel sections,and it depends greatly on the width to thickness ratio of each plate of the sections. The calculation results of Chinese code,AISI( American Iron and Steel Institiute) standard,Australian / New Zealand standard and the formula proposed by Zhu Aizhu are in conservatively agreement with the test results,while that of Eurocode is a little larger. The suitability of the improved method from Chinese Code was theoretically proved,and it can get a little safer results with a lower coefficient of variation,which means appropriate to be used in practice.