通过柱脚铰接变截面轻型门式刚架1／3缩尺模型拟静力试验，得到了结构的承载力、破坏模式、延性、耗能、刚度、柱顶侧移，以及承载力和刚度的退化规律等，并基于试验结果分析了结构的抗震性能和影响结构整体性能的因素，如局部屈曲、楔率、翼缘的宽厚比及腹板的高厚比等。试验结果表明，变截面门式刚架结构的破坏模式为形成3个“屈曲铰”的机构：2个铰位于梁的两个端部，1个位于梁跨中截面薄弱处；该种结构形式延性、耗能能力较差，但由于自重轻，地震作用力小，结构能较好的满足抗震设防要求。%To study the hysteretic behavior of steel portal frame structures, an experiment has been carried out on a 1/3 scaled model of a single-story single-bay steel portal frame with tapered members under cyclic loading. Based on the test result, the bearing capacity, failure mode, ductility, energy dissipation, transverse stiffness, drift at top of column, and degradation of strength and stiffness have been obtained, and the seismic behavior of the frame has been analyzed, together with the influencing factors, such as local buckling, member＇ s tapering ratio, flange width-thickness ratio and web width-thickness ratio, etc. Test result reveals that the failure mode of the model belongs to a three ＇ buckling hinges＇ mechanism ： two of them located at beam end adjacent to the columns, and the other one at the weakest section of beam near mid-span; The ductility and energy dissipation of this structural system are very poor, but the system can satisfy the demand of seismic code very well due to small earthquake force from small self-weight.
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