非對稱斷面鋼骨鋼筋混凝土(SRC)梁柱構材極限強度之研究

Abstract

過去國內外對鋼骨鋼筋混凝土(Steel Reinforced Concrete，簡稱SRC)柱及梁柱構材的研究較著重於探討雙對稱斷面構材的軸向載重、偏心載重、軸力-彎矩等之行為，極少探討非對稱斷面之SRC構材之行為，唯為於工程實務上有較廣之應用，非對稱的T字型鋼骨斷面或鋼骨偏心斷面之SRC構材實有深入研究之必要性。 本研究係以實驗的方式，探討含T字型鋼骨斷面非對稱包覆型SRC短柱的單向載重及SRC梁柱軸力-彎矩載重之行為。試驗規劃以鋼骨型式、鋼骨含量、軸力比及偏心距為試體參數。在SRC短柱的軸壓強度上，試驗結果顯示在相同的箍筋間距、鋼骨含量與鋼筋比下，偏心量與鋼骨型式於軸向極限強度之影響甚小。在非對稱斷面SRC梁柱構材方面，試驗參數對其極限彎矩強度及剩餘強度的表現有顯著的影響，且正、負向之極限彎矩強度差異甚大。試驗結果與各規範之預測值比較，顯示ACI規範與AIJ規範皆能準確的預測此種非對稱斷面SRC梁柱之軸力與彎矩強度關係。

Researches on steel reinforced concrete (SRC) columns during the past few decades were focused on the symmetrical structural steel shape. This research conducted experimental studies to investigate the behavior and ultimate strength of concrete-encased steel columns having unsymmetrical T-shape structural steel section. Twenty specimens including six short SRC columns and fourteen SRC beam-columns were designed and constructed. The short columns were loaded monotonically to failure while the beam-columns were subjected to axial load as well as flexural bending simultaneously. Variables to be studied included the shape of structural steel, the ratio of the area of structural steel shape to concrete section, the effect of axial load and the eccentricity of structural steel shape. Effects of various experimental parameters on the behavior were discussed. The experimental results were summarized and presented. The results indicate that ACI Building Code and AIJ SRC Standards can predict well the load carrying capacities of the SRC columns having unsymmetrical structural steel shape.