大地震中建築結構的底層柱同時承擔垂直以及彎矩荷重，於柱底部降伏後可能會伴隨局部挫屈現象，進而導致強度衰減以及鋼柱的軸向變形，震後損傷修復須處理鋼板複雜的變形以及底層柱所負擔的高垂直荷重，使得修復過程較其他結構構件困難，需要使用重型支撐機以及現場切削、熱整形及焊接等作業，不僅消耗許多的人力資源以及時間成本外，較長的復原時間也會造成受災戶心理及生活上的壓力，為減低上述修復上的困難，使結構物快速回復原有的性能，本研究提出新型的切削式箱型鋼柱，於箱型柱的底部內側底部增設斷面小、高強度的核心柱，使其在大變形底下仍然保持彈性並且負擔垂直以及彎矩荷重，且為了維持此區域的柱斷面與其餘斷面相近，於核心柱區域的外柱進行四面切削開口方式以減少斷面積，在地震中塑性行為將集中在切削區域附近，震後針對外柱的切削區域進行補強可恢復耐震性能，能夠減少修復上的困難。
本研究設計了兩組足尺箱型柱試體，並以靜態反覆加載的實驗評估其性能，結果顯示切削式箱型柱最大強度與一般箱型柱接近，可達到層間變位角5.0%兩個迴圈，至加載結束強度呈現穩定的遲滯迴圈，實驗過程無明顯的挫屈發生，由應變分布趨勢可以觀察到切削式箱型柱的塑性區域集中在切削孔的左右兩側，而核心柱至加載結束除了靠近內柱焊接鋼板處有進入塑性外其餘區域保持彈性。數值模擬結果顯示，在中等軸力下的兩試體耐震性能差異更顯著，切削式箱型柱的最大強度可以維持外，軸向壓縮量有顯著的改善且數值模擬中無明顯的局部挫曲，塑性範圍集中於切削孔周圍，而核心柱區域塑性範圍集中於上下兩端以及核心柱上下焊接的鋼板以及加勁板，核心柱保持部分彈性可以支撐結構垂直以及彎矩荷重，符合設計的預期。

This study proposed a new type of reduced section column. A core column with a smaller section and high strength is added at the bottom of the inner side of the box column, and the outer column in the core column area is cut with openings to control the total section areas of the columns. In this way, the plastic behavior would concentrate in the reduced area under the earthquake, and the core column can maintain the elasticity to sustain the vertical and horizontal loads. In the post-seismic repair stage, the reduced area of the outer column can be strengthened to restore the seismic performance by localized heat forming or simple welded steel plate.
Two sets of full-scale box columns were tested, and the test results show that the maximum strength of reduced section columns is close to the normal column, both show stable hysteresis behaviors. For the reduced section column, the plastic area is concentrated in the reduced region of the outer columns, while the core columns remain elastic at the end of loading. The numerical analysis shows that the difference in vibration resistance between the two specimens is more significant while the columns sustained higher axial forces. The maximum strength of the reduced section column can be maintained, the axial shortening is significantly smaller than that of the normal column and the plasticity area is concentrated in the reduced area of the outer column, while the core column maintains part of the elasticity.

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