中文摘要：

高强度钢材（屈服强度≥460MPa）已经在国内外多个钢结构实际工程中得到应用，但关于其受压构件整体稳定性的研究还很少，特别是屈服强度超过690MPa的超高强度钢材。针对两种超高强度钢材S690和S960（名义屈服强度分别为690MPa和960MPa），进行了端部带约束的受压构件整体稳定受力性能的试验研究，试验共包括8个试件。基于试验结果，分析该类钢材构件的失稳破坏形态和屈曲承载力，利用经过验证的有限元模型计算其整体稳定系数，并与欧洲规范和我国规范的柱子曲线进行对比分析。结果表明，超高强度钢材受压构件整体稳定系数的试验值要明显高于其所在的b类柱子曲线，甚至比欧洲规范的‰类柱子曲线和我国规范的a类柱子曲线还要高出很多。这说明超高强度钢材受压柱的屈曲强度较普通强度钢材的屈曲强度有明显提高。这些试验研究和有限元分析成果为完善我国超高强度钢材的稳定设计方法和设计理论提供了重要的试验依据和前提条件，并有利于超高强度钢材在我国钢结构工程中得到更广泛的应用和发展。

英文摘要：

High strength steels with nominal yield strength more than 460MPa have been employed in the construction of steel structures, though research on the buckling behavior of the steel welded section columns lacks, especially for ultra- high strength steels with nominal yield strength more than 690MPa. The overall buckling behavior of ultra-high strength steel compression members with end restraints was experimentally studied using eight specimens, including two types of ultra-high strength structural steels, S690 and S960, with nominal yield strength of 690MPa and 960MPa, respectively. Based on the test results, the buckling mode and the loading capacity of the ultra-high strength steel columns were analyzed, and the buckling strength of the columns were calculated by using a finite element model verified and compared with the column curves in the European and the Chinese codes for steel structures design, respectively. It was shown that the buckling strength of the ultra-high strength steel compression columns with end restraints was much higher than that calculated from column curve b according to the European and the Chinese code, and than the curve a0 in the European code and curve a in the Chinese code. The buckling strength of ultra-high strength steel columns was improved significantly, when compared with ordinary strength steel columns on a nondimensional basis.